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# List of DDT Observations




Please note that obs_start_time is in UT, not local time.

Clicking on the Sequence Number link will take you to the title and abstract of the proposal.

Clicking on the ObsID link will take you to the results of our search in ADS for articles we were able to link to the ObsID. Our database extends to publications that appeared three months or more ago and does not include meeting abstracts.

A 'D' in the prop_time column means a proprietary time of 1-3 months, with the default being 3 months. A '3' means a proprietary time of three months. An 'N' means the data is public.

Click here for table only

### Accepted/Approved DDT Time By Cycle from Cycle 1

CycleApproved TimeRequested Time
011601068
02906.51441
03859.4771982
04468.78989.5
057251333
063731090.8
07196.6645.4
081218.21916
09707.2741
101062333
11218623
124971019
13392803
14427723.1
1544011375
16662.81119.8
178371389
18862.81996.8
19646.51452.5
20785.21645
2110001481
227671509
23206876

### DDTs from Sep 1, 2021 to Present (Jul 4, 2022)

Target NameCategoryPIRequested
Time
Approved
Time
InstrumentGratingProprietary
Time
Submission
Date
GRB220611ASN, SNR AND ISOLATED NSLevan1515ACIS-SNONENJun 15 2022 10:24AM
IGRJ17091-3624BH AND NS BINARIESWang3030ACIS-SHETGDJun 2 2022 10:54AM
Swift J095520.7+690400.9BH AND NS BINARIESBrightman1010ACIS-SNONENMay 6 2022 1:53PM
GRB 220412BBH AND NS BINARIESGompertz4040ACIS-SNONEDApr 26 2022 11:11AM
Wolf 359STARS AND WDHoward3636ACIS-SHETGNMar 22 2022 11:12PM
AT 2018hyzACTIVE GALAXIES AND QUASARSCendes1515ACIS-SNONEDFeb 17 2022 12:09PM
SDSS J143016.05+230344.4ACTIVE GALAXIES AND QUASARSJiang25060ACIS-SNONE1Jan 29 2022 10:46AM
SGRB211106ABH AND NS BINARIESRouco Escorial4040ACIS-SNONEDDec 20 2021 12:32PM
SGRB 210726ABH AND NS BINARIESSchroeder4040ACIS-SNONEDDec 9 2021 2:41PM
47 TucBH AND NS BINARIESPaduano2020ACIS-SNONENNov 24 2021 3:18AM
GLEAM-X J162759.5-523504.3SN, SNR AND ISOLATED NSHurley-Walker3030ACIS-SNONEDNov 22 2021 6:31AM
GRB210905ASN, SNR AND ISOLATED NSMARGUTTI2020ACIS-SNONENNov 3 2021 12:46PM
IC 10 X-1BH AND NS BINARIESBinder3030ACIS-SNONENOct 21 2021 4:38PM
ERO_TDE_1ACTIVE GALAXIES AND QUASARSMalyali3030HRC-INONEDOct 20 2021 5:38PM
SN 2021aabpSN, SNR AND ISOLATED NSHo2020ACIS-SNONEDOct 8 2021 10:47AM
EXO 2030+375BH AND NS BINARIESPradhan3010ACIS-SHETGDSep 10 2021 10:42AM

CycleSequence NumberObsIDInstrumentGratingApproved Exposure TimeActual Exposure TimeTargetStatusApproval DateStart Time [UT]Proprietary TimePI Name

2350337126441ACIS-SNONE15.00000015.080647GRB220611Aarchived Jun 15 2022 7:22PM  Jun 23 2022 11:57PM NLevan
2340236126435ACIS-SHETG30.00000030.080045IGRJ17091-3624observed Jun 2 2022 12:12PM  Jun 16 2022 11:42AM DWang
2340236026421ACIS-SNONE10.00000010.082040SwiftJ095520.7+6904archived May 11 2022 9:13AM  Jun 4 2022 11:51AM NBrightman
2340235926407ACIS-SNONE40.00000040.102883GRB220412Bobserved Apr 27 2022 12:42PM  May 2 2022 7:25AM DGompertz
2320153026388ACIS-SHETG12.00000012.000000Wolf359scheduled Apr 1 2022 7:18PM  Jul 1 2022 8:05PM NHoward
2320152926387ACIS-SHETG12.00000012.000000Wolf359scheduled Apr 1 2022 7:18PM  Jun 30 2022 7:50PM NHoward
2320152826386ACIS-SHETG12.00000011.059200Wolf359archived Apr 1 2022 7:18PM  Jun 28 2022 10:49PM NHoward
2370461026350ACIS-SNONE15.00000015.080562AT2018hyzarchived Feb 24 2022 1:38PM  Mar 19 2022 11:12AM DCendes
2370460326330ACIS-SNONE4.0000004.204800SDSSJ143016.05+2303archived Feb 7 2022 3:41PM  Mar 16 2022 6:02PM 1Jiang
2370460326329ACIS-SNONE4.0000004.104715SDSSJ143016.05+2303archived Feb 7 2022 3:41PM  Mar 16 2022 1:23AM 1Jiang
2370460326328ACIS-SNONE4.0000004.149000SDSSJ143016.05+2303archived Feb 7 2022 3:41PM  Mar 14 2022 4:11AM 1Jiang
2370460326327ACIS-SNONE4.0000004.104000SDSSJ143016.05+2303archived Feb 7 2022 3:41PM  Mar 13 2022 8:17AM 1Jiang
2370460326326ACIS-SNONE4.0000004.092500SDSSJ143016.05+2303archived Feb 7 2022 3:41PM  Mar 11 2022 2:49PM 1Jiang
2370460326325ACIS-SNONE4.0000004.089988SDSSJ143016.05+2303archived Feb 7 2022 3:41PM  Mar 9 2022 1:12PM 1Jiang
2370460326324ACIS-SNONE4.0000004.091500SDSSJ143016.05+2303archived Feb 7 2022 3:41PM  Mar 7 2022 11:50PM 1Jiang
2370460326323ACIS-SNONE4.0000004.090758SDSSJ143016.05+2303archived Feb 7 2022 3:41PM  Mar 6 2022 10:09AM 1Jiang
2370460326322ACIS-SNONE4.0000004.091000SDSSJ143016.05+2303archived Feb 7 2022 3:41PM  Mar 3 2022 11:01PM 1Jiang
2370460326321ACIS-SNONE4.0000004.091870SDSSJ143016.05+2303archived Feb 7 2022 3:41PM  Mar 2 2022 9:54AM 1Jiang
2370460326320ACIS-SNONE4.0000004.092000SDSSJ143016.05+2303archived Feb 7 2022 3:41PM  Feb 28 2022 9:51PM 1Jiang
2370460326319ACIS-SNONE4.0000004.091383SDSSJ143016.05+2303archived Feb 7 2022 3:41PM  Feb 27 2022 7:31AM 1Jiang
2370460326318ACIS-SNONE4.0000004.091000SDSSJ143016.05+2303archived Feb 7 2022 3:41PM  Feb 25 2022 4:13AM 1Jiang
2370460326317ACIS-SNONE4.0000004.091500SDSSJ143016.05+2303archived Feb 7 2022 3:41PM  Feb 23 2022 1:27AM 1Jiang
2370460326316ACIS-SNONE4.0000004.090000SDSSJ143016.05+2303archived Feb 7 2022 2:39PM  Feb 21 2022 3:46AM 1Jiang
2240235526286ACIS-SNONE10.0000009.95999147Tucarchived Jan 14 2022 12:19PM  Jan 27 2022 2:32AM NPaduano
2250337026282ACIS-SNONE10.00000010.111420GLEAM-XJ162759.5-52archived Jan 10 2022 12:17PM  Jan 23 2022 6:25AM DHurley-Walker
2240235726262ACIS-SNONE19.00000018.463645SGRB211106Aarchived Dec 21 2021 12:13PM  Jan 5 2022 3:49AM DRoucoEscorial
2240235726249ACIS-SNONE21.00000019.962000SGRB211106Aarchived Dec 20 2021 12:41PM  Jan 4 2022 3:21PM DRoucoEscorial
2240235626247ACIS-SNONE40.00000036.753000SGRB210726Aarchived Dec 13 2021 10:50AM  Dec 31 2021 7:10PM DSchroeder
2240235526229ACIS-SNONE10.0000009.78000047Tucarchived Dec 6 2021 9:08AM  Jan 26 2022 3:48PM NPaduano
2250337026228ACIS-SNONE20.00000020.090522GLEAM-XJ162759.5-52archived Nov 26 2021 1:53PM  Jan 22 2022 9:13PM DHurley-Walker
2250336926205ACIS-SNONE20.00000019.409637GRB210905Aarchived Nov 4 2021 12:17PM  Nov 24 2021 1:28PM NMARGUTTI
2270458626189HRC-INONE30.00000030.123471ERO_TDE_1archived Oct 28 2021 11:41AM  Nov 10 2021 11:50PM DMalyali
2240235426188ACIS-SNONE30.00000030.073100IC10X-1archived Oct 28 2021 11:04AM  Jan 7 2022 6:26AM NBinder
2250336826159ACIS-SNONE20.00000019.889600SN2021aabparchived Oct 8 2021 12:28PM  Oct 15 2021 8:05AM DHo
2240235326154ACIS-SHETG10.00000010.080000EXO2030+375archived Sep 30 2021 5:15PM  Oct 20 2021 3:43AM DPradhan
2250329625093ACIS-SNONE20.00000020.090218GRB210704Aarchived Jul 13 2021 9:05AM  Jul 19 2021 1:50AM DTroja
2230050225092HRC-SLETG30.00000030.040830V1674Herarchived Jul 12 2021 9:04AM  Jul 19 2021 7:59AM NDrake
2230050125089HRC-SNONE10.00000010.134432TCPJ18573095+165339archived Jul 3 2021 5:11PM  Jul 10 2021 1:30AM NMaccarone
2240229825079ACIS-SHETG30.00000028.0580004U1543-475archived Jun 13 2021 1:38PM  Jun 21 2021 9:23AM NMiller
2250329525064ACIS-SNONE19.00000018.288000AT2020mrfarchived Jun 7 2021 11:20AM  Jun 19 2021 8:21AM NYao
2240229625063ACIS-SHETG12.50000012.625000MAXIJ1803-298archived Jun 7 2021 11:19AM  Jun 18 2021 5:21AM DDiazTrigo
2270429325060HRC-SLETG28.00000028.038000AT2019avdarchived Jun 2 2021 12:05PM  Jun 9 2021 8:08PM NPasham
2270429325056HRC-SLETG22.00000021.877601AT2019avdarchived May 31 2021 3:16PM  Jun 8 2021 4:49PM NPasham
2240229725054ACIS-SNONE30.00000029.947334MAXIJ1348-630archived May 14 2021 4:32PM  Jun 28 2021 6:01AM DCarotenuto
2250329525050ACIS-SNONE21.00000020.091000AT2020mrfarchived May 13 2021 10:36AM  Jun 18 2021 10:29AM NYao
2250329425049ACIS-SNONE60.00000060.053200CXOJ134856.4+263944archived May 12 2021 9:33AM  Jun 2 2021 11:43PM DLin
2240229625041ACIS-SHETG12.50000012.627000MAXIJ1803-298archived May 10 2021 11:29AM  Jun 17 2021 8:29PM DDiazTrigo
2240229525040ACIS-SHETG25.00000023.700000MAXIJ1803-298archived May 10 2021 11:29AM  May 23 2021 7:30PM DDiazTrigo
2240229425039ACIS-SHETG25.00000025.100000MAXIJ1803-298archived May 10 2021 11:29AM  May 17 2021 9:15AM DDiazTrigo
2270429225025ACIS-SHETG50.00000050.079943NGC4151archived Apr 23 2021 9:46AM  May 3 2021 10:37AM DMiller
2250329325016ACIS-SNONE30.00000030.066227FRB20201124Aarchived Apr 16 2021 12:40PM  Apr 20 2021 5:28AM DPiro
2250329225005HRC-INONE2.0000002.180175ASASSN-20hxarchived Mar 30 2021 2:15PM  Apr 16 2021 7:35AM NMandal
2240229324986ACIS-SNONE10.00000010.091968SwiftJ130456-493158archived Mar 4 2021 2:05PM  Mar 10 2021 4:06AM NBrightman
2250329124966ACIS-SNONE25.00000025.070248ASKAPJ173608.2-3216archived Feb 12 2021 11:16AM  Feb 17 2021 2:51PM NKaplan
2250329024965ACIS-SNONE25.00000024.590441GRB190610Aarchived Feb 8 2021 10:52AM  Feb 26 2021 7:53AM NTohuvavohu
2170428724911ACIS-SNONE15.00000015.069599PKS1127-14archived Dec 18 2020 9:28AM  Jan 1 2021 7:34PM DSiemiginowska
2150328924910ACIS-SNONE25.00000025.317039GRB201214Barchived Dec 16 2020 5:27PM  Jan 11 2021 2:29PM DTroja
2150328824909ACIS-SNONE25.00000025.054200GRB201214Barchived Dec 16 2020 5:27PM  Dec 22 2020 5:35PM DTroja
2170428624876ACIS-SNONE30.00000029.059377ESO253-G003archived Nov 18 2020 2:02PM  Jan 21 2021 8:11PM DPayne
2170428524875ACIS-SNONE30.00000028.061200ESO253-G003archived Nov 18 2020 2:02PM  Dec 26 2020 12:11PM DPayne
2110020424847HRC-INONE10.00000010.006307Saturnarchived Oct 19 2020 8:53AM  Nov 23 2020 11:01PM NWeigt
2110020424846HRC-INONE10.00000010.136482Saturnarchived Oct 19 2020 8:53AM  Nov 21 2020 12:31PM NWeigt
2110020424845HRC-INONE10.00000010.125976Saturnarchived Oct 19 2020 8:46AM  Nov 19 2020 11:48AM NWeigt
2150328724841ACIS-SNONE5.0000005.078000SGR1830-0645archived Oct 10 2020 4:38PM  Oct 13 2020 9:51PM NKouveliotou
2170428324755ACIS-SNONE30.00000030.060798RXJ1756.4+5235archived Sep 28 2020 3:41AM  Nov 5 2020 4:02AM NKoss
2170425424667ACIS-SHETG23.00000022.639115Mrk279archived Sep 21 2020 4:16PM  Oct 3 2020 4:09AM DMiller
2170425424666ACIS-SHETG23.00000022.943727Mrk279archived Sep 21 2020 4:16PM  Sep 30 2020 8:08AM DMiller
2170425424665ACIS-SHETG23.00000022.943436Mrk279archived Sep 21 2020 4:16PM  Sep 29 2020 1:43PM DMiller
2170425424662ACIS-SHETG31.00000031.884800Mrk279archived Sep 16 2020 7:18AM  Sep 28 2020 4:18PM DMiller
2140228224651ACIS-SHETG25.00000025.070399AT2019wey/SRGarchived Sep 9 2020 12:18PM  Sep 20 2020 5:59PM NKulkarni
2170425124640ACIS-SNONE20.00000020.0567832MASXJ01110461-4558archived Aug 24 2020 5:43AM  Sep 16 2020 4:12PM DLin
2150327824619ACIS-SNONE30.00000030.054932PSRJ1846-0258archived Aug 13 2020 3:35PM  Sep 15 2020 10:39AM NBlumer
2140219823360ACIS-SHETG15.00000015.078000herculesx-1archived Jul 31 2020 9:39AM  Aug 14 2020 10:05PM DKosec
2140219823356ACIS-SHETG35.00000035.077750herculesx-1archived Jul 20 2020 9:03AM  Aug 12 2020 5:43AM DKosec
2150320723331ACIS-SNONE10.00000010.092000SN2012auarchived Jul 9 2020 1:37PM  Jul 20 2020 8:08AM DMARGUTTI
2150320723316ACIS-SNONE10.0000009.912000SN2012auarchived Jun 30 2020 3:19PM  Jul 19 2020 5:05PM DMARGUTTI
2150320623315ACIS-SNONE12.00000012.356394SN2020nlbarchived Jun 30 2020 10:17AM  Jul 12 2020 4:34AM DSand
2150320623314ACIS-SNONE63.00000062.680954SN2020nlbarchived Jun 29 2020 3:06PM  Jul 10 2020 12:16AM DSand
2170404923300ACIS-SHETG30.00000030.077106Mrk335archived Jun 22 2020 12:38PM  Jul 4 2020 2:17AM NBoissay-Malaquin
2170404923299ACIS-SHETG30.00000030.079173Mrk335archived Jun 22 2020 12:38PM  Jul 3 2020 8:29AM NBoissay-Malaquin
2170404923298ACIS-SHETG30.00000030.079257Mrk335archived Jun 22 2020 12:38PM  Jul 2 2020 2:15AM NBoissay-Malaquin
2170404923297ACIS-SHETG30.00000030.076502Mrk335archived Jun 22 2020 12:38PM  Jul 1 2020 9:25AM NBoissay-Malaquin
2170404923292ACIS-SHETG30.00000030.080000Mrk335archived Jun 19 2020 5:44PM  Jun 30 2020 4:41PM NBoissay-Malaquin
2170404823289ACIS-SNONE50.00000047.409000AT2018fykarchived Jun 16 2020 10:25AM  Jun 29 2020 5:34AM NWevers
2150320523285ACIS-SNONE20.00000019.962000GRB190829Aarchived Jun 11 2020 11:03AM  Jun 29 2020 7:15PM DTroja
2140219723266ACIS-SNONE30.00000030.092837NGC7793P13archived May 11 2020 9:42AM  Jun 4 2020 4:57PM NWalton
2150320423251ACIS-SNONE20.00000019.061460SGRJ1935+2154archived May 6 2020 2:50PM  May 18 2020 11:04AM DGogus
2110019323232HRC-SLETG3.3000003.492431C/2019Y4ATLASarchived Apr 13 2020 2:44PM  Apr 28 2020 7:59PM DBodewits
2110019323231HRC-SLETG3.3000003.494481C/2019Y4ATLASarchived Apr 13 2020 2:44PM  Apr 28 2020 6:56PM DBodewits
2110019323230HRC-SLETG3.3000003.494481C/2019Y4ATLASarchived Apr 13 2020 2:44PM  Apr 28 2020 5:52PM DBodewits
2110019323229HRC-SLETG3.3000003.496531C/2019Y4ATLASarchived Apr 13 2020 2:44PM  Apr 28 2020 4:49PM DBodewits
2110019323228HRC-SLETG3.3000003.492431C/2019Y4ATLASarchived Apr 13 2020 2:44PM  Apr 28 2020 3:45PM DBodewits
2110019323227HRC-SLETG3.3000003.494481C/2019Y4ATLASarchived Apr 13 2020 2:44PM  Apr 28 2020 2:42PM DBodewits
2110019323226HRC-SLETG3.3000003.490125C/2019Y4ATLASarchived Apr 13 2020 2:44PM  Apr 28 2020 1:38PM DBodewits
2110019323225HRC-SLETG3.3000003.496531C/2019Y4ATLASarchived Apr 13 2020 2:44PM  Apr 28 2020 12:35PM DBodewits
2110019323224HRC-SLETG3.6000003.641056C/2019Y4ATLASarchived Apr 10 2020 5:52PM  Apr 28 2020 11:26AM DBodewits
2150320323209ACIS-SNONE30.00000030.059561J1818-1607archived Mar 24 2020 1:50PM  Apr 3 2020 5:48AM DBlumer
2130046923179ACIS-SNONE25.00000023.376000Haro1-10archived Feb 19 2020 1:52PM  Jun 8 2020 5:13PM DLucy
2130046823178ACIS-SNONE10.0000009.849000IRAS15175-4508archived Feb 19 2020 1:52PM  May 18 2020 5:30PM DLucy
2150320223172ACIS-SNONE10.00000010.050200SN2020bvcarchived Feb 12 2020 5:07PM  Feb 29 2020 2:15AM NHo
2150320123171ACIS-SNONE10.00000010.055784SN2020bvcarchived Feb 12 2020 5:07PM  Feb 16 2020 8:31PM NHo
2120134423148HRC-INONE5.0000005.042232Betelgeusearchived Jan 29 2020 3:26PM  Aug 15 2020 11:56AM NKashyap
2120134323147HRC-INONE5.0000005.159850Betelgeusearchived Jan 29 2020 3:26PM  Feb 17 2020 7:32PM NKashyap
2150320023141ACIS-SNONE10.00000010.090736SN2020oiarchived Jan 21 2020 2:09PM  Mar 13 2020 9:53AM DStroh
2150319923140ACIS-SNONE10.00000010.090829SN2020oiarchived Jan 21 2020 2:09PM  Feb 15 2020 1:25AM DStroh
2150319823133ACIS-SNONE10.00000010.058177SN2019yvqarchived Jan 17 2020 10:42AM  Feb 6 2020 6:16AM NPooley
2170403623132ACIS-SNONE5.0000005.111237SDSSJ1539+3954archived Jan 17 2020 10:38AM  Jun 18 2020 12:11AM NNi
2040219623116ACIS-SNONE15.00000015.0567004FGLJ0336.0+7502archived Dec 18 2019 2:37PM  Jan 25 2020 12:00PM NLi
2030046723108ACIS-SNONE50.00000048.112000RAqrarchived Dec 12 2019 4:50PM  Jan 12 2020 12:13AM 3Karovska
2070403223107ACIS-SNONE25.00000027.053700PSOJ047.4479+27.299archived Dec 12 2019 1:34PM  Mar 24 2020 8:50PM Nmoretti
2040219523106ACIS-SNONE10.0000009.945600NGC4045archived Dec 10 2019 3:28PM  Dec 31 2019 6:11AM NBrightman
2010019223093HRC-SNONE12.50000012.688476C/2019Q4Borisovarchived Nov 27 2019 12:58PM  Dec 18 2019 6:49PM NSnios
2010019223092HRC-SNONE12.50000012.662082C/2019Q4Borisovarchived Nov 27 2019 12:58PM  Dec 18 2019 3:12PM NSnios
2010019223091HRC-SNONE12.50000012.690782C/2019Q4Borisovarchived Nov 27 2019 12:58PM  Dec 17 2019 1:39AM NSnios
2010019223090HRC-SNONE12.50000012.655932C/2019Q4Borisovarchived Nov 27 2019 12:58PM  Dec 16 2019 10:02PM NSnios
2010019223089HRC-SNONE12.50000012.694882C/2019Q4Borisovarchived Nov 27 2019 12:58PM  Dec 16 2019 8:02AM NSnios
2050319723082ACIS-SNONE18.00000017.971999FRB180916.J0158+65archived Nov 13 2019 4:46PM  Dec 18 2019 4:01AM DScholz
2050319723081ACIS-SNONE18.00000018.070654FRB180916.J0158+65archived Nov 13 2019 4:25PM  Dec 3 2019 1:46AM DScholz
2010019222919HRC-SNONE12.50000012.534982C/2019Q4Borisovarchived Oct 22 2019 3:16PM  Dec 16 2019 4:25AM NSnios
2070402822918ACIS-SNONE4.0000004.062914PKS1413+135archived Oct 18 2019 9:57AM  Jun 18 2020 11:00PM NLiodakis
2070402822917ACIS-SNONE4.0000004.063425PKS1413+135archived Oct 18 2019 9:57AM  May 4 2020 12:19AM NLiodakis
2070402822916ACIS-SNONE4.0000004.061000PKS1413+135archived Oct 18 2019 9:57AM  Mar 22 2020 5:28AM NLiodakis
2070402822915ACIS-SNONE4.0000004.057900PKS1413+135archived Oct 18 2019 9:57AM  Feb 3 2020 6:10PM NLiodakis
2070402822914ACIS-SNONE4.0000004.064100PKS1413+135archived Oct 18 2019 9:13AM  Dec 20 2019 11:30PM NLiodakis
2010019122913ACIS-SNONE1.0000001.048585V1298Tauarchived Oct 17 2019 8:23PM  Nov 17 2019 2:54PM NPoppenhaeger
2040219422886ACIS-SHETG30.00000030.084319GRS1915+105archived Oct 11 2019 4:19PM  Nov 30 2019 9:04AM DMiller
2040219322885ACIS-SHETG30.00000030.044101GRS1915+105archived Oct 11 2019 4:19PM  Nov 3 2019 9:08AM DMiller
2050319622848ACIS-SNONE20.00000020.090037AT2019osyarchived Sep 6 2019 2:00PM  Sep 22 2019 9:33PM NJaodand
2030046622845ACIS-SHETG30.00000029.948800V3890Sgrarchived Aug 29 2019 3:41PM  Sep 3 2019 7:29AM NOrio
2030046522682ACIS-SNONE15.00000015.082639V1369Cenarchived Jul 29 2019 11:01AM  Sep 2 2019 3:00AM DDrake
2040212322289ACIS-SNONE30.00000030.070602SwiftJ1728.9-3613archived Jul 16 2019 11:35AM  Jul 28 2019 5:19AM DMiller
2040212222285ACIS-SNONE10.0000009.5580004U1901+03archived Jul 9 2019 1:45PM  Jul 14 2019 7:41AM NLutovinov
2040212122277ACIS-SHETG25.00000026.6520004U1820-30archived Jul 3 2019 1:55PM  Jul 8 2019 1:09PM NHeinke
2040212122276ACIS-SHETG25.00000026.9090004U1820-30archived Jul 3 2019 11:35AM  Jul 7 2019 5:22PM NHeinke
2050314922271ACIS-SNONE15.00000015.091639SN2003gkarchived Jun 17 2019 10:22AM  Aug 5 2019 3:47PM NPatnaude
2070389722240ACIS-SHETG10.00000010.069509PKS1830-211archived May 22 2019 1:06PM  Jun 16 2019 4:22PM DBuson
2070389622239ACIS-SHETG10.00000010.070393PKS1830-211archived May 22 2019 1:06PM  Jun 15 2019 10:43PM DBuson
2040211722213ACIS-SHETG30.00000030.078001GRS1915+105archived Apr 25 2019 11:45AM  Apr 30 2019 4:49AM DMiller
2070389222212ACIS-SNONE20.00000020.082000SDSSJ085051archived Apr 22 2019 2:33PM  May 12 2019 6:37PM NCivano
2070388722199ACIS-SHETG25.00000025.995974PKS1830-211archived Apr 15 2019 12:45PM  May 24 2019 8:25PM NBuson
2070388622198ACIS-SHETG20.00000020.069181PKS1830-211archived Apr 15 2019 12:45PM  May 7 2019 12:51PM NBuson
2070388522197ACIS-SHETG15.00000014.069199PKS1830-211archived Apr 15 2019 12:45PM  Apr 19 2019 7:16AM NBuson
2020126622186ACIS-SHETG12.60000012.647713ProximaCentauriarchived Apr 8 2019 4:41PM  May 6 2019 4:05AM DMacGregor
2020126522185ACIS-SHETG12.60000013.062752ProximaCentauriarchived Apr 8 2019 4:41PM  May 3 2019 3:58AM DMacGregor
2070387922183ACIS-SNONE10.00000010.108726NAMEAT2019ahkarchived Apr 5 2019 11:22AM  Jun 9 2019 12:47AM DAlexander
2070387822182ACIS-SNONE10.00000010.109100NAMEAT2019ahkarchived Apr 5 2019 11:22AM  Apr 17 2019 12:57PM DAlexander
2010018222159HRC-INONE36.00000036.101783Jupiterarchived Mar 12 2019 6:23PM  May 29 2019 3:43AM NGladstone
2040211522134HRC-INONE2.0000002.1824814U1901+03archived Feb 14 2019 5:10PM  Mar 5 2019 5:57PM NHemphill
2070386322096ACIS-SNONE80.00000073.566101GSN069archived Jan 31 2019 12:33PM  Feb 14 2019 4:52PM DMiniutti
2040211422095ACIS-SNONE15.00000015.090000SXP4.78archived Jan 30 2019 4:59PM  Mar 1 2019 1:20AM NLutovinov
1970384122021ACIS-SNONE1.5000001.426000GraL1817+27archived Nov 30 2018 11:42AM  May 30 2019 3:06AM DPooley
1970384022020ACIS-SNONE1.5000001.612000GraL1721+88archived Nov 30 2018 11:42AM  May 30 2019 2:12AM DPooley
1970383922019ACIS-SNONE1.5000001.592900GraL1537-30archived Nov 30 2018 11:42AM  May 11 2019 7:53AM DPooley
1970383822018ACIS-SNONE1.5000001.692600GraL0659+16archived Nov 30 2018 11:42AM  Jan 15 2019 2:26PM DPooley
1970383722017ACIS-SNONE1.5000001.608900WISEJ2344-3056archived Nov 30 2018 11:42AM  Apr 16 2019 3:38AM DPooley
1970383622016ACIS-SNONE1.5000001.610558SDSSJ1251+2935archived Nov 30 2018 11:42AM  Mar 16 2019 6:21AM DPooley
1970383522015ACIS-SNONE1.5000001.608770DESJ0420-4037archived Nov 30 2018 11:42AM  May 10 2019 9:35PM DPooley
1970383422014ACIS-SNONE1.5000001.612000DESJ0405-3308archived Nov 30 2018 11:42AM  May 13 2019 12:46AM DPooley
1970383322013ACIS-SNONE1.5000001.608679DESJ0029-3814archived Nov 30 2018 11:42AM  Jan 29 2019 10:08AM DPooley
1920126422012ACIS-SNONE20.00000019.064912HD60848archived Nov 30 2018 11:26AM  Dec 30 2018 1:30AM DRauw
1940211321868ACIS-SNONE20.00000019.948800GS1354-64archived Sep 26 2018 4:18PM  Oct 8 2018 6:22AM DReynolds
1940211221866ACIS-SNONE3.0000003.090700ESO338-IG04HLX-1archived Sep 21 2018 3:35PM  Nov 19 2018 1:39AM DOskinova
1920126321855ACIS-SNONE20.00000020.171700OMCDiskSamplearchived Sep 7 2018 5:24PM  Dec 11 2018 11:29PM NCleeves
1920126221854ACIS-SNONE20.00000020.058950OMCDiskSamplearchived Sep 7 2018 5:24PM  Dec 5 2018 10:50AM NCleeves
1970383221732ACIS-SNONE10.00000010.062600TXS2116-077archived Aug 20 2018 10:29AM  Sep 15 2018 8:42AM DPaliya
1930046121671HRC-SLETG10.0000009.766457VWHyiarchived Aug 5 2018 2:13PM  Aug 8 2018 12:29AM NKnigge
1950314021660ACIS-SNONE20.00000020.088000SN2012auarchived Jul 17 2018 3:50PM  Aug 2 2018 1:57PM DPatnaude
1950305321122HRC-SLETG50.00000047.288378AT18cowarchived Jun 21 2018 1:05PM  Jun 24 2018 3:21PM NMaccarone
1920120621102HRC-INONE30.00000030.146533ALPHABOOarchived May 24 2018 9:20AM  Jun 10 2018 7:57PM SAYRES
1970367921097ACIS-SNONE10.00000010.080000SDSSJ110731.23+1347archived May 9 2018 8:55AM  Jun 14 2018 3:47AM NChilingarian
1970367821091ACIS-SNONE10.00000010.074876NGC3893archived Apr 19 2018 3:33PM  Jun 28 2018 11:41AM NMcHardy
1940202521090ACIS-SNONE47.00000046.610473GW170817archived Apr 18 2018 3:51PM  May 5 2018 1:25AM NWilkes
1940202621083ACIS-SHETG30.00000030.079042SwiftJ1658.2-4242archived Apr 16 2018 1:48PM  Apr 28 2018 1:26AM DPonti
1950304321082ACIS-SNONE23.00000023.091000SN2011jaarchived Apr 11 2018 3:00PM  Dec 6 2018 1:03AM SPatnaude
1940202521080ACIS-SNONE53.00000051.456900GW170817archived Apr 11 2018 9:41AM  May 3 2018 10:41AM NWilkes
1970367721076ACIS-SNONE10.0000009.972748M87archived Apr 2 2018 9:13PM  Apr 24 2018 1:48PM NWong
1970367621075ACIS-SNONE10.00000010.069495M87archived Apr 2 2018 9:13PM  Apr 22 2018 12:19AM NWong
1970367521058HRC-INONE15.00000014.7797323C264archived Mar 20 2018 11:20AM  Apr 4 2018 7:08PM NSantander
1950305221040ACIS-SNONE20.00000020.050800iPTF14hlsarchived Mar 6 2018 7:18AM  Apr 4 2018 1:10PM DMARGUTTI
1970367421033ACIS-SNONE11.30000011.352200UGC416archived Feb 26 2018 12:39PM  Sep 9 2018 3:35PM SGallo
1970367321032ACIS-SNONE9.6000009.653400LSBCF570-05archived Feb 26 2018 12:39PM  Jun 28 2018 8:36AM SGallo
1970367221031ACIS-SNONE8.4000008.474345UGC11578archived Feb 26 2018 12:39PM  Aug 5 2018 12:06PM SGallo
1970367121030ACIS-SNONE7.8000007.852300UGC10015archived Feb 26 2018 12:39PM  May 7 2018 9:09PM SGallo
1970367021029ACIS-SNONE7.7000007.963900UGC10017archived Feb 26 2018 12:39PM  May 17 2018 3:52AM SGallo
1970366921028ACIS-SNONE7.4000007.650720UGC09927archived Feb 26 2018 12:39PM  May 6 2018 2:56PM SGallo
1970366821027ACIS-SNONE6.9000006.792100UGC05750archived Feb 26 2018 12:39PM  Mar 21 2018 12:17PM SGallo
1970366721026ACIS-SNONE6.7000006.754900UGC04669archived Feb 26 2018 12:39PM  May 23 2018 9:51PM SGallo
1970366621025ACIS-SNONE5.8000005.691445UGC1230archived Feb 26 2018 12:39PM  Nov 14 2018 5:50AM SGallo
1970366521024ACIS-SNONE5.8000005.852800UGC05005archived Feb 26 2018 12:39PM  Jun 19 2018 4:26PM SGallo
1970366421023ACIS-SNONE15.60000015.070960LSBCF583-04archived Feb 26 2018 12:39PM  May 24 2018 9:33PM SGallo
1970366321022ACIS-SNONE12.60000012.654111LSBCF576-01archived Feb 26 2018 12:39PM  Aug 13 2018 11:20AM SGallo
1970366221021ACIS-SNONE10.40000010.450100LSBCF743-01archived Feb 26 2018 12:39PM  Sep 2 2018 7:07AM SGallo
1970366121020ACIS-SNONE7.1000007.154491LSBCF612-01archived Feb 26 2018 12:39PM  Sep 24 2018 8:47PM SGallo
1970366021019ACIS-SNONE6.5000006.553400LSBCF544-01archived Feb 26 2018 12:39PM  Nov 14 2018 3:44AM SGallo
1970365921018ACIS-SNONE6.4000006.451100UGC09024archived Feb 26 2018 12:39PM  Apr 4 2018 3:50AM SGallo
1970365821017ACIS-SNONE9.0000009.048900LSBCF750-04archived Feb 26 2018 12:39PM  Aug 26 2018 11:56PM SGallo
1970365721016ACIS-SNONE7.4000007.449300IC3605archived Feb 26 2018 12:39PM  Apr 3 2018 2:35PM SGallo
1970365621015ACIS-SNONE7.1000006.990500UGC06151archived Feb 26 2018 12:39PM  Mar 21 2018 10:03AM SGallo
1970365521014ACIS-SNONE6.7000006.742500LSBCF570-06archived Feb 26 2018 12:39PM  Nov 25 2018 11:32AM SGallo
1970365421013ACIS-SNONE6.1000006.150214UGC05629archived Feb 26 2018 12:39PM  Jul 2 2018 8:59PM SGallo
1970365321012ACIS-SNONE5.9000005.952000LSBCF574-09archived Feb 26 2018 12:39PM  Apr 14 2018 10:37AM SGallo
1970365221011ACIS-SNONE4.8000004.854437UGC05675archived Feb 26 2018 12:39PM  Mar 21 2018 8:26AM SGallo
1970365121010ACIS-SNONE3.6000003.492606UGC08839archived Feb 26 2018 12:39PM  Apr 3 2018 5:04PM SGallo
1970365021009ACIS-SNONE3.6000003.651473LSBCF574-07archived Feb 26 2018 12:39PM  May 10 2018 2:20PM SGallo
1970364921008ACIS-SNONE3.2000003.297175LSBCF574-08archived Feb 26 2018 12:39PM  Jun 25 2018 9:22PM SGallo
1970364821007ACIS-SNONE3.2000003.253765CGCG098-132archived Feb 26 2018 12:39PM  Jun 8 2018 11:49AM SGallo
1970364721006ACIS-SNONE3.2000003.329400LSBCF570-04archived Feb 26 2018 12:39PM  Jun 10 2018 12:24AM SGallo
1950305121005ACIS-SNONE22.00000021.963000SN2013dfarchived Feb 26 2018 12:38PM  Mar 26 2018 8:10PM SPatnaude
1950305021004ACIS-SNONE15.00000015.090000SN2003gkarchived Feb 26 2018 12:38PM  Aug 21 2018 2:14AM SPatnaude
1950304921003ACIS-SNONE22.00000022.092000SN2013akarchived Feb 26 2018 12:38PM  Aug 5 2018 8:04PM SPatnaude
1950304821002ACIS-SNONE10.00000010.092000SN2013byarchived Feb 26 2018 12:38PM  Jun 19 2018 5:42AM SPatnaude
1950304721001ACIS-SNONE10.00000010.091451SN2012awarchived Feb 26 2018 12:38PM  Mar 26 2018 4:54PM SPatnaude
1950304621000ACIS-SNONE10.00000010.091748SN2013ejarchived Feb 26 2018 12:38PM  Sep 30 2018 8:35PM SPatnaude
1950304520999ACIS-SNONE15.00000015.089764SN2008axarchived Feb 26 2018 12:38PM  Nov 6 2018 2:46AM SPatnaude
1950304420998ACIS-SNONE20.00000020.091000SN2011dharchived Feb 26 2018 12:38PM  Aug 31 2018 4:28PM SPatnaude
1950304320997ACIS-SNONE19.00000020.990564SN2011jaarchived Feb 26 2018 12:38PM  Apr 24 2018 9:33PM SPatnaude
1920120620996HRC-INONE50.00000050.055878ALPHABOOarchived Feb 26 2018 12:37PM  Jun 9 2018 10:06AM SAYRES
1940202420995ACIS-SNONE17.00000016.244000NGC5907archived Feb 22 2018 9:22AM  Mar 1 2018 4:42AM DPintore
1940202420994ACIS-SNONE33.00000033.049100NGC5907archived Feb 21 2018 10:51PM  Feb 27 2018 1:40PM DPintore
1920120520987HRC-INONE5.0000005.180350ALPHACENTAURIarchived Feb 16 2018 9:52AM  May 18 2018 5:25PM NAYRES
1940202220966ACIS-SNONE10.00000010.069904NGC300ULX-1archived Jan 26 2018 10:21PM  Feb 11 2018 4:49PM DVasilopoulos
1940202120965ACIS-SNONE10.00000010.070236NGC300ULX-1archived Jan 26 2018 10:21PM  Feb 8 2018 3:10AM DVasilopoulos
1940202020945ACIS-SNONE13.00000014.405700GW170817archived Jan 18 2018 4:25PM  Jan 28 2018 4:29AM NWilkes
1940202020939ACIS-SNONE19.70000022.541809GW170817archived Jan 7 2018 10:35PM  Jan 24 2018 8:18AM NWilkes
1940202020938ACIS-SNONE16.00000016.067231GW170817archived Jan 7 2018 10:35PM  Jan 21 2018 1:45PM NWilkes
1940202020937ACIS-SNONE19.10000021.045162GW170817archived Jan 7 2018 10:34PM  Jan 23 2018 8:02AM NWilkes
1940202020936ACIS-SNONE32.20000032.168700GW170817archived Jan 5 2018 2:26PM  Jan 17 2018 9:55PM NWilkes
1840201920928ACIS-SNONE10.00000010.068146LAMOSTJ061149+22493archived Dec 22 2017 1:17PM  Jan 13 2018 3:23PM DLiu
1870347020887ACIS-SNONE22.50000020.654316QSOJ1342+0928archived Dec 1 2017 12:31PM  Dec 17 2017 7:01AM DBanados
1820120420875ACIS-SNONE4.0000004.091577DMTauarchived Nov 22 2017 11:54AM  Jan 25 2018 8:15AM NCleeves
1820120320874ACIS-SNONE4.0000004.092000DMTauarchived Nov 22 2017 11:54AM  Jan 17 2018 7:57PM NCleeves
1820120220873ACIS-SNONE4.0000004.092000DMTauarchived Nov 22 2017 11:54AM  Jan 9 2018 10:33PM NCleeves
1820120120872ACIS-SNONE4.0000004.092000DMTauarchived Nov 22 2017 11:54AM  Jan 4 2018 11:59AM NCleeves
1820120020871ACIS-SNONE4.0000004.090868DMTauarchived Nov 22 2017 11:54AM  Dec 27 2017 3:11PM NCleeves
1820119920870ACIS-SNONE4.0000004.092000DMTauarchived Nov 22 2017 11:54AM  Dec 21 2017 6:48AM NCleeves
1820119820869ACIS-SNONE4.0000004.092000DMTauarchived Nov 22 2017 11:54AM  Dec 14 2017 12:03AM NCleeves
1840201220861ACIS-SNONE25.00000025.068738GW170817archived Nov 16 2017 11:52AM  Dec 6 2017 11:02AM NWilkes
1840201220860ACIS-SNONE75.00000075.066017GW170817archived Nov 16 2017 11:48AM  Dec 3 2017 1:59AM NWilkes
1840201120859ACIS-SHETG25.00000025.090000SwiftJ0243.6+6124archived Nov 8 2017 1:06PM  Nov 11 2017 11:20AM DDegenaar
1880180320851ACIS-INONE34.00000031.734444eMACSJ0324.0+2421archived Nov 6 2017 4:45PM  Jan 2 2018 1:17AM NEbeling
1810017120847HRC-INONE25.00000025.050233Uranusarchived Oct 29 2017 1:57PM  Nov 12 2017 1:14PM DDunn
1810017120846HRC-INONE25.00000025.144533Uranusarchived Oct 29 2017 12:00PM  Nov 11 2017 7:47PM DDunn
1820119720831ACIS-SNONE10.00000010.065700AT2017gblarchived Oct 17 2017 3:45PM  Nov 3 2017 12:18PM NHeikkila
1840201020830ACIS-SNONE50.00000051.946700NGC5907ULXarchived Oct 17 2017 12:11PM  Nov 7 2017 6:11AM Dbelfiore
1850303420728ACIS-SNONE50.00000047.309100GRB170817Aarchived Aug 29 2017 12:49PM  Sep 1 2017 3:43PM DTroja
1830040320632HRC-SLETG35.00000034.406433NovaLup2016archived Aug 11 2017 3:25PM  Aug 30 2017 3:37PM NOrio
1870361620625ACIS-SNONE10.00000010.061465AT2017eqxarchived Jul 31 2017 3:41PM  Aug 16 2017 10:53AM DNicholl
1850303320613ACIS-SNONE15.00000015.059262GRB170714Aarchived Jul 24 2017 4:32PM  Jul 28 2017 11:57AM NTroja
1870347020124ACIS-SNONE27.50000025.059603QSOJ1342+0928archived Jul 12 2017 4:47PM  Dec 15 2017 1:55PM DBanados
1870346920115ACIS-SNONE10.00000010.089000SDSSJ135750.71+22310archived Jun 29 2017 7:05PM  Aug 27 2017 7:51AM NChilingarian
1870346820114ACIS-SNONE10.00000010.092000SDSSJ110731.23+13471archived Jun 29 2017 7:05PM  Jul 17 2017 12:21AM NChilingarian
1840189420098HRC-SNONE30.00000030.092977MAXIJ0911-655archived Jun 1 2017 12:26PM  Jun 25 2017 7:07AM DRiggio
1840189320083ACIS-SNONE8.0000007.678800SWIFTJ175233.9-2909archived May 15 2017 4:03PM  May 25 2017 3:36AM NMaccarone
1850297320055ACIS-SNONE50.00000051.010332SN2017cbvarchived Mar 23 2017 2:47PM  Mar 27 2017 11:54AM DDrout
1840189220054ACIS-INONE65.00000065.099750PSRB1259-63archived Mar 17 2017 11:23AM  Apr 24 2017 5:27AM NPavlov
1870346620035ACIS-SNONE14.40000014.469199M87archived Feb 27 2017 7:29PM  Apr 14 2017 2:13AM NNeilsen
1870346620034ACIS-SNONE14.40000014.467599M87archived Feb 27 2017 3:14PM  Apr 12 2017 12:00AM NNeilsen
1870346520021ACIS-SNONE10.00000010.049712WPVS007archived Feb 16 2017 5:44PM  Mar 16 2017 3:24PM NGrupe
1840189120008ACIS-SHETG30.00000030.071250GRS1716-249archived Jan 31 2017 1:22PM  Feb 6 2017 12:24PM DMiller
1810016820002HRC-INONE36.00000036.164821Jupiterarchived Jan 26 2017 2:50PM  Aug 6 2017 2:08AM NJackman
1810016720001HRC-INONE36.00000037.147283Jupiterarchived Jan 26 2017 2:50PM  Jun 18 2017 6:57PM NJackman
1810016620000HRC-INONE72.00000072.138735Jupiterarchived Jan 26 2017 2:50PM  Feb 28 2017 12:53PM NJackman
1850297219999ACIS-SNONE10.0000009.978900iPTF17cwarchived Jan 23 2017 5:25PM  Feb 8 2017 9:39AM DCorsi
1770346419990ACIS-SNONE30.00000030.090000SDSSJ140737.16+4428archived Jan 11 2017 10:36AM  Feb 25 2017 2:51PM DSecrest
1750297119986ACIS-SNONE30.00000029.771358CRTSCSS161010J0458archived Dec 21 2016 4:13PM  Jul 23 2017 9:17PM DMARGUTTI
1750297019985ACIS-SNONE30.00000027.416074CRTSCSS161010J0458archived Dec 21 2016 4:13PM  Feb 13 2017 12:16PM DMARGUTTI
1750296919984ACIS-SNONE30.00000030.045200CRTSCSS161010J0458archived Dec 21 2016 4:13PM  Jan 13 2017 11:32PM DMARGUTTI
1730040119983HRC-SLETG50.00000050.185284ASASSN-16oharchived Dec 19 2016 2:25PM  Dec 28 2016 9:27PM DMaccarone
1740189019904ACIS-SHETG30.00000031.0527504U1630-47archived Oct 6 2016 2:17PM  Oct 21 2016 1:43AM DBhattacharyya
1740188919891ACIS-SNONE35.00000036.302609CXOUJ103844.8+53300archived Sep 22 2016 2:40PM  Oct 22 2016 4:32PM NEarnshaw
1720115419793HRC-INONE11.25000010.889601ProximaCenarchived Sep 6 2016 5:03PM  Dec 8 2016 8:29PM NWargelin
1720115319790HRC-INONE11.25000010.889729ProximaCenarchived Sep 1 2016 4:40PM  Nov 3 2016 6:43PM NWargelin
1720115219789HRC-INONE11.25000010.922401ProximaCenarchived Sep 1 2016 4:40PM  Oct 14 2016 6:31PM NWargelin
1720115119788HRC-INONE11.25000012.464001ProximaCenarchived Sep 1 2016 4:40PM  Sep 26 2016 8:12AM NWargelin
1740188819787ACIS-SHETG15.00000015.040450SMCX-3archived Aug 30 2016 11:23AM  Sep 7 2016 4:45PM DCoe
1740188819786ACIS-SHETG25.00000024.042227SMCX-3archived Aug 30 2016 11:18AM  Sep 6 2016 7:50PM DCoe
1740188119691ACIS-INONE1.0000001.081900PMNJ0032-7306archived Aug 3 2016 2:10PM  Aug 11 2016 11:00PM DKennea
1750296319690ACIS-SNONE60.00000056.230900PSRJ1119-6127archived Aug 2 2016 6:22PM  Oct 27 2016 6:38PM NBlumer
1730039218889ACIS-SNONE18.00000018.027750FOAqrarchived Jul 14 2016 11:46AM  Jul 26 2016 7:26AM NKennedy
1740181918885ACIS-SNONE25.00000025.535198XMMUJ004855.5-73494archived Jun 30 2016 11:04AM  Jul 6 2016 8:43AM NVasilopoulos
1750266718884ACIS-SNONE20.00000020.069599SGR1935+2154archived Jun 29 2016 3:51PM  Jul 7 2016 5:43AM DKouveliotou
1750266618880ACIS-SNONE30.00000029.047000Gaia16apdarchived Jun 27 2016 12:27PM  Mar 19 2017 5:29PM DYan
1750266518879ACIS-SNONE30.00000030.032422Gaia16apdarchived Jun 27 2016 12:27PM  Oct 23 2016 6:11PM DYan
1750266418878ACIS-SNONE47.00000044.185500PKS1613-50archived Jun 23 2016 2:38PM  Jun 25 2016 9:30AM DRea
1750266318827ACIS-SNONE15.00000015.081000SN2016bkvarchived Apr 1 2016 1:03PM  Apr 20 2016 4:10AM NPatnaude
1740181818815ACIS-SNONE30.00000030.090000HETEJ1900.1-2455archived Mar 17 2016 5:15PM  Apr 18 2016 10:09PM DDegenaar
1770330118813ACIS-SNONE5.0000005.068768M87archived Mar 9 2016 8:02PM  Mar 17 2016 3:43AM NCheung
1770330018812ACIS-SNONE5.0000004.853443M87archived Mar 9 2016 8:02PM  Mar 16 2016 12:27AM NCheung
1770329918811ACIS-SNONE5.0000005.069200M87archived Mar 9 2016 8:02PM  Mar 14 2016 1:44PM NCheung
1770329818810ACIS-SNONE5.0000005.069600M87archived Mar 9 2016 8:02PM  Mar 13 2016 7:25AM NCheung
1770329718809ACIS-SNONE5.0000004.984400M87archived Mar 9 2016 8:02PM  Mar 12 2016 5:07AM NCheung
1770329618804ACIS-SNONE30.00000030.062316QSO2237+0305archived Mar 9 2016 1:39PM  Apr 24 2016 5:27AM NPooley
1750266218802ACIS-SNONE36.00000036.062177SN2005iparchived Mar 2 2016 12:16PM  Apr 4 2016 2:16AM NMauerhan
1730039118800ACIS-SNONE25.00000025.103556MWC560archived Feb 25 2016 5:26PM  Mar 9 2016 2:20AM DLucy
1730039118790ACIS-SNONE25.00000025.101000MWC560archived Feb 23 2016 2:41PM  Mar 8 2016 7:17AM DLucy
1770329518789ACIS-SNONE30.00000029.978798Mrk1018archived Feb 18 2016 12:45PM  Feb 25 2016 2:37AM DTremblay
1740181718788ACIS-SNONE5.0000004.956140PSRJ2032+4127archived Feb 15 2016 5:13PM  Feb 24 2016 8:23AM NHo
1750266118760ACIS-SNONE5.0000005.025100ASASSN16atarchived Jan 26 2016 11:14AM  Feb 6 2016 6:57AM NGrupe
1620108418725ACIS-SNONE20.00000020.094000HD97658archived Dec 3 2015 10:31AM  Mar 5 2016 4:21PM DWheatley
1620108418724ACIS-SNONE20.00000020.094000HD97658archived Dec 3 2015 9:52AM  Dec 11 2015 1:01PM DWheatley
1650266018717ACIS-SNONE40.00000040.092000FRB121102archived Nov 19 2015 11:14AM  Nov 23 2015 10:37AM DScholz
1640181618686HRC-SNONE2.8000002.938931SMCX-2archived Oct 1 2015 5:25PM  Nov 5 2015 6:56PM NLi
1670328018352ACIS-SNONE10.00000010.124600NGC660archived Jul 22 2015 3:32PM  Aug 26 2015 8:37PM NAnnuar
1610015517709ACIS-SNONE110.000000107.221501Pluto(134340)archived Jul 15 2015 3:19PM  Aug 1 2015 9:30PM NMcNutt
1610015517708ACIS-SNONE16.00000017.595600Pluto(134340)archived Jul 15 2015 3:19PM  Jul 30 2015 5:30AM NMcNutt
1640169817704ACIS-SNONE28.00000028.752000V404Cygarchived Jul 14 2015 3:56PM  Jul 25 2015 6:46PM NHeinz
1610015517703ACIS-SNONE14.00000014.088741Pluto(134340)archived Jul 9 2015 1:59PM  Jul 27 2015 12:09AM NMcNutt
1640169717701ACIS-SHETG40.00000040.035879V404Cygarchived Jul 2 2015 3:23PM  Jul 11 2015 1:17PM NNeilsen
1640169617697ACIS-SHETG25.00000024.712915v404Cygarchived Jun 22 2015 7:37PM  Jun 23 2015 9:40PM NKing
1640169517696ACIS-SHETG30.00000029.307864v404Cygarchived Jun 19 2015 9:29AM  Jun 22 2015 1:56PM NKing
1640169417678ACIS-INONE10.00000010.102500M82archived Jun 5 2015 2:09PM  Jun 21 2015 3:12AM NBrightman
1650249317673ACIS-SNONE10.00000010.061636SNhunt275archived May 26 2015 3:17PM  Sep 20 2015 11:42PM NMARGUTTI
1650249217672ACIS-SNONE10.00000010.046760SNhunt275archived May 26 2015 3:17PM  Jun 8 2015 2:04AM NMARGUTTI
1640169317662ACIS-INONE5.0000005.0809002S1553-542archived May 13 2015 4:36PM  May 21 2015 4:53PM DLutovinov
1640169217661HRC-SNONE30.00000029.765233SAXJ1808.4-3658archived May 11 2015 2:47PM  May 24 2015 10:29PM DPatruno
1650249117658ACIS-SNONE25.00000023.643700GRB150423Aarchived Apr 28 2015 3:13PM  May 2 2015 7:39AM NBerger
1640169117649ACIS-SHETG30.00000030.0730001RXSJ180408.9-34205archived Apr 7 2015 1:46PM  Apr 14 2015 3:08PM DDegenaar
1630033817648ACIS-SHETG35.00000034.947201GKPerseiarchived Mar 29 2015 7:31AM  Apr 4 2015 8:21AM NOrio
1620102617644ACIS-SNONE40.00000038.690798RWAurarchived Mar 20 2015 3:47PM  Apr 16 2015 6:56AM NSchneider
1650249017639ACIS-SNONE50.00000047.108715CasACCOarchived Mar 9 2015 4:35PM  May 1 2015 2:18AM NPosselt
1640169017637ACIS-SNONE10.00000010.075000[PFH2005]622archived Mar 4 2015 2:19PM  Mar 6 2015 4:48PM NBurrows
1670315517636ACIS-SNONE10.00000010.056400WPVS007archived Mar 4 2015 9:08AM  Mar 28 2015 8:20AM NGrupe
1640168917631HRC-INONE10.00000010.153651FRB150215archived Feb 15 2015 11:51PM  Feb 18 2015 4:11AM DPetroff
1640168817630ACIS-SHETG15.00000014.4576004U1700-37archived Feb 12 2015 5:51PM  Feb 22 2015 3:30AM NOskinova
1670315417594ACIS-SNONE15.00000015.058837SWIFTJ123205.1-1056archived Jan 14 2015 5:56PM  Feb 10 2015 5:35AM NLevan
1650248917586ACIS-SNONE15.00000015.066000SwiftJ123205.1-1056archived Jan 6 2015 2:57PM  Jan 9 2015 11:55AM NTroja
1550248817571ACIS-SNONE10.00000010.056279SN2014Carchived Dec 15 2014 12:02PM  Aug 28 2015 9:03AM NMARGUTTI
1550248717570ACIS-SNONE10.00000010.024851SN2014Carchived Dec 15 2014 12:02PM  Apr 20 2015 10:47PM NMARGUTTI
1550248617569ACIS-SNONE10.00000010.045655SN2014Carchived Dec 15 2014 12:02PM  Jan 30 2015 3:22PM NMARGUTTI
1570315217567HRC-SLETG45.00000044.793784ASASSN-14liarchived Dec 4 2014 5:21PM  Dec 11 2014 9:09AM NMiller
1570315217566HRC-SLETG35.00000035.039883ASASSN-14liarchived Dec 4 2014 4:24PM  Dec 8 2014 11:29PM NMiller
1540168617559ACIS-SNONE40.00000040.114000CXOJ122518.6+144545archived Nov 26 2014 11:33AM  Dec 15 2014 6:27AM DHeida
1540168517558ACIS-SNONE20.00000019.985700CXOJ122518.6+144545archived Nov 26 2014 11:33AM  Dec 8 2014 5:42PM DHeida
1550248517550ACIS-SNONE20.00000020.058751PSNJ12215757+042818archived Nov 4 2014 4:44PM  Nov 16 2014 3:28PM NMARGUTTI
1570315117547ACIS-SNONE5.0000005.071600NGC247archived Oct 22 2014 11:11AM  Nov 12 2014 5:54AM DFeng
1570315017538ACIS-SNONE20.00000020.078069SDSSJ152304.97+1145archived Sep 26 2014 9:55AM  Dec 26 2014 4:59AM DGallo
1550247917314ACIS-SNONE30.00000029.154750SGR1935+2154archived Aug 7 2014 3:43PM  Aug 31 2014 12:59AM DRea
1520096816631ACIS-SNONE25.00000023.011038V1180Casarchived Jun 20 2014 3:48PM  Aug 2 2014 10:11PM NNucita
1540161516625ACIS-SNONE5.0000005.147250PSRB1259-63archived Jun 16 2014 12:48PM  Jun 25 2014 7:03PM NBordas
1540161416624ACIS-SNONE5.0000005.174750PSRB1259-63archived Jun 16 2014 12:48PM  Jun 23 2014 6:46PM NBordas
1550227116618ACIS-SNONE20.00000020.063200GRB140515Aarchived May 20 2014 1:07PM  May 25 2014 7:54AM NMARGUTTI
1540161316606ACIS-SHETG35.00000035.082250GROJ1744-28archived Mar 22 2014 7:58PM  Mar 31 2014 12:48AM DMiller
1540161316605ACIS-SHETG35.00000035.073250GROJ1744-28archived Mar 22 2014 6:28PM  Mar 29 2014 7:09PM DMiller
1540161216596ACIS-SHETG10.00000010.077500GROJ1744-28archived Feb 17 2014 5:12PM  Mar 3 2014 9:15AM DKennea
1440161116583ACIS-INONE30.00000028.538149PSRB1259-63archived Jan 23 2014 6:17PM  Feb 9 2014 7:49AM NPavlov
1550226916580ACIS-SNONE50.00000047.465954SN2014Jarchived Jan 23 2014 12:03PM  Feb 3 2014 8:26PM NMARGUTTI
1520096716577ACIS-SNONE10.0000009.964800KOI-314archived Jan 21 2014 1:27PM  Feb 7 2014 9:42PM DPoppenhaeger
1440161116563ACIS-INONE35.00000032.061376PSRB1259-63archived Dec 19 2013 4:13PM  Feb 8 2014 1:42PM NPavlov
1440161016561ACIS-SNONE30.00000030.578400XSSJ12270-4859archived Dec 16 2013 1:33PM  Jan 11 2014 5:14AM DPatruno
1450226816556ACIS-SNONE20.00000019.064984SN2013gearchived Dec 2 2013 12:21PM  Dec 7 2013 6:08PM NMARGUTTI
1450226616488ACIS-SNONE50.00000046.073786GRB130925Aarchived Oct 1 2013 2:36PM  Oct 6 2013 4:22AM DBellm
1450226516441ACIS-SNONE15.00000015.069100GRB130831Aarchived Sep 9 2013 3:31PM  Oct 3 2013 1:27PM DDePasquale
1450226416440ACIS-SNONE15.00000014.641300GRB130831Aarchived Sep 9 2013 3:31PM  Sep 17 2013 1:21AM DDePasquale
1450203715663ACIS-SNONE30.00000029.964800GRB130606Aarchived Jun 12 2013 10:10AM  Jun 17 2013 3:29AM DBerger
1460109915648ACIS-SNONE25.00000025.062680[SRW2012]Src.3carchived May 9 2013 3:19PM  May 24 2013 12:22PM NRoberts
1470292315647ACIS-SHETG30.00000030.554400Mrk590archived May 2 2013 9:55AM  Jun 16 2013 7:33AM NMathur
1440154115646ACIS-SNONE15.00000013.753555NGC404archived Apr 26 2013 5:16PM  Jun 4 2013 2:44AM NKaaret
1440154015645HRC-SNONE53.00000053.041959IGRJ18245-2452archived Apr 26 2013 10:08AM  Apr 29 2013 12:24AM DPatto
1410009515641ACIS-SNONE5.0000005.183200Comet2011L4(PANSTarchived Mar 20 2013 4:41PM  Apr 24 2013 12:47AM NLisse
1410009415640ACIS-SNONE5.0000005.180100Comet2011L4(PANSTarchived Mar 20 2013 4:39PM  Apr 21 2013 2:39PM NLisse
1410009315639ACIS-SNONE5.0000005.177000Comet2011L4(PANSTarchived Mar 20 2013 4:38PM  Apr 17 2013 9:44AM NLisse
1470292215637ACIS-SNONE15.00000015.0691002XMMIJ184725.1-6317archived Mar 18 2013 5:51PM  Mar 29 2013 4:28AM DLin
1410009715631HRC-INONE5.0000005.181632Comet2011L4(PANSTarchived Mar 14 2013 10:19PM  Apr 24 2013 2:21AM NLisse
1410009615630HRC-INONE5.0000005.189832Comet2011L4(PANSTarchived Mar 14 2013 10:19PM  Apr 17 2013 11:17AM NLisse
1410009515629ACIS-SNONE5.0000005.071600Comet2011L4(PANSTarchived Mar 14 2013 10:19PM  Apr 23 2013 11:15PM NLisse
1410009415628ACIS-SNONE5.0000005.074700Comet2011L4(PANSTarchived Mar 14 2013 10:19PM  Apr 21 2013 1:07PM NLisse
1410009315627ACIS-SNONE5.0000005.070699Comet2011L4(PANSTarchived Mar 14 2013 10:19PM  Apr 17 2013 8:12AM NLisse
1490109515625ACIS-SNONE10.0000009.964770NuSTARJ163433-4738.archived Mar 11 2013 3:12PM  Mar 23 2013 8:46AM DTomsick
1430031815620HRC-INONE5.0000005.179582M31N2013-01barchived Mar 1 2013 12:52PM  Mar 11 2013 11:16PM NHenze
1450203215616ACIS-SNONE2.0000002.064600M82archived Feb 11 2013 5:01PM  Feb 24 2013 11:25PM NMadej
1320091015597ACIS-SNONE25.00000025.074440CRTSMLS121106J0144archived Nov 19 2012 8:10PM  Nov 23 2012 5:02PM DVianello
1330031715596HRC-SLETG25.00000025.119933NovaMon2012archived Nov 19 2012 2:11PM  Dec 3 2012 8:01PM NOrio
1370292015584ACIS-SNONE25.00000024.966258SwiftJ1644+57archived Nov 1 2012 10:24AM  Nov 26 2012 10:25AM NTanvir
1330031615495ACIS-SHETG25.00000025.049135PNVJ06393874+055352archived Aug 29 2012 4:40PM  Sep 12 2012 9:13AM NNess
1350202115268ACIS-SNONE20.00000020.068815GRB120804Aarchived Aug 7 2012 2:47PM  Aug 13 2012 11:11AM NTroja
1350202015265HRC-INONE10.00000010.1241821E2259+586archived Jul 31 2012 12:04PM  Aug 21 2012 4:51PM DKas
1350180014464ACIS-SNONE10.00000010.068800GRB120624Barchived Jun 28 2012 11:30AM  Jun 30 2012 9:24AM NCampana
1340143514442ACIS-SNONE20.00000020.065073NGC4088archived May 25 2012 4:51PM  Jun 2 2012 3:30AM DMezcua
1340143414441ACIS-SHETG20.00000019.0732504U1630-47archived May 24 2012 2:28PM  Jun 3 2012 10:28PM DNeilsen
1340143014428ACIS-SHETG20.00000020.103500SwiftJ1753.5-0127archived Apr 26 2012 12:18PM  May 3 2012 3:25PM DSoleri
1330031214426HRC-SLETG20.00000020.189682NovaLMC2012archived Apr 17 2012 6:34PM  Apr 26 2012 10:12PM NDrake
1340142914425ACIS-SHETG30.00000030.088300MAXIJ1305-704archived Apr 16 2012 2:32PM  Apr 29 2012 7:20PM DMiller
1350179714420ACIS-SNONE20.00000020.398000PTF11qcjarchived Mar 28 2012 2:18PM  Apr 11 2012 8:55AM NCorsi
1350179614412ACIS-SNONE40.00000039.641600SN2011jaarchived Mar 13 2012 2:26PM  Apr 3 2012 5:10AM DRay
1320083014402ACIS-SNONE20.00000020.06959955Cncarchived Feb 23 2012 2:57PM  Apr 5 2012 1:03PM DWheatley
1320082914401ACIS-SNONE12.00000011.78639955Cncarchived Feb 23 2012 2:56PM  Mar 7 2012 2:11AM DWheatley
1350179414398ACIS-SNONE10.00000010.062600PTF11qcjarchived Feb 9 2012 12:09PM  Feb 26 2012 9:15AM NCorsi
1350179314382ACIS-SNONE10.0000009.961085PTF11qcjarchived Dec 27 2011 1:24PM  Jan 13 2012 1:43AM NCorsi
1340142714376ACIS-SNONE2.0000002.010400NGC891ULX1archived Dec 5 2011 4:45PM  Dec 20 2011 7:12AM NHodges-Kluck
1350179214360ACIS-SNONE20.00000021.010349CXOUJ164710.2-45521archived Oct 12 2011 11:14AM  Oct 23 2011 3:56PM DIsrael
1250179114341ACIS-SNONE40.00000049.715200PTF11klyarchived Aug 26 2011 10:09AM  Aug 27 2011 11:00AM NHughes
1240142514337ACIS-SHETG14.00000014.047270IGRJ17498-2921archived Aug 24 2011 8:50AM  Aug 29 2011 2:22PM NDiSalvo
1240142514336ACIS-SHETG16.00000016.345000IGRJ17498-2921archived Aug 19 2011 3:02PM  Aug 30 2011 1:36PM NDiSalvo
1250178914329ACIS-SNONE15.00000014.350399SwiftJ1834.9-0846archived Aug 11 2011 2:56AM  Aug 22 2011 3:46PM NKargaltsev
1250178814237ACIS-SNONE10.00000010.043925GRB110709Barchived Aug 3 2011 2:39PM  Oct 31 2011 8:15PM NLevan
1250156713511HRC-INONE1.0000001.181953SwiftJ1822.3-1606archived Jul 18 2011 2:48PM  Jul 28 2011 8:21PM DKouveliotou
1270258213423HRC-INONE5.0000005.187525SWIFTJ2058.4+0516archived Jun 13 2011 12:57PM  Jun 22 2011 3:04PM NCenko
1240130013420HRC-INONE1.0000001.530581M15archived May 18 2011 4:15PM  May 30 2011 4:54PM NSivakoff
1250156313419ACIS-SNONE5.0000005.043424SNRG306.3-0.9archived May 6 2011 2:58PM  Jun 2 2011 2:06PM NMiller
1270258113418ACIS-SNONE10.00000010.040058PS1-10jharchived Apr 29 2011 10:54AM  May 22 2011 11:16PM NGezari
1240129713252ACIS-SNONE40.00000040.080000PSRJ1748-2446amarchived Mar 31 2011 10:28AM  Apr 29 2011 5:30PM DDegenaar
1220073513250ACIS-SLETG20.00000020.075300TWHyaarchived Mar 29 2011 4:23PM  Apr 13 2011 12:00PM NGuenther
1240129513237ACIS-SNONE40.00000040.077250HESSJ0632+057archived Feb 9 2011 2:40PM  Feb 13 2011 9:28PM DTorres
1240129313225ACIS-SNONE30.00000030.078000PSRJ1748-2446amarchived Jan 24 2011 2:02PM  Feb 17 2011 9:31AM DWijnands
1240129213219ACIS-SHETG12.00000012.000000CygX-1archived Jan 19 2011 9:47AM  Feb 5 2011 6:56AM NMcClintock
1250154913217ACIS-SNONE15.00000015.010343XTEJ1810-197archived Jan 12 2011 12:23AM  Feb 9 2011 12:04AM DPerna
1260098213212ACIS-SNONE10.00000010.186400NGC1589-OTarchived Dec 23 2010 3:54PM  Jan 16 2011 3:58AM NFilippenko
1250154813210ACIS-SNONE5.0000005.000000Crabarchived Dec 14 2010 12:26PM  Oct 15 2011 4:51AM NWeisskopf
1250154713209ACIS-SNONE5.0000005.000000Crabarchived Dec 14 2010 12:26PM  Sep 15 2011 4:09AM NWeisskopf
1250154613208ACIS-SNONE5.0000005.000000Crabarchived Dec 14 2010 12:26PM  Aug 15 2011 9:01AM NWeisskopf
1250154513207ACIS-SNONE5.0000005.000000Crabarchived Dec 14 2010 12:26PM  Apr 12 2011 2:15PM NWeisskopf
1250154413206ACIS-SNONE5.0000005.000000Crabarchived Dec 14 2010 12:26PM  Mar 15 2011 6:04AM NWeisskopf
1250154313205ACIS-SNONE5.0000005.000000Crabarchived Dec 14 2010 12:26PM  Feb 16 2011 4:52PM NWeisskopf
1250154213204ACIS-SNONE5.0000003.323628Crabarchived Dec 14 2010 12:26PM  Jan 15 2011 12:07AM NWeisskopf
1270251113203ACIS-SNONE16.00000016.046587ULASJ1120+0641archived Dec 13 2010 12:51PM  Feb 4 2011 12:08PM DSimpson
1240129113171ACIS-SNONE4.0000003.7553481RXSJ192430.2+51014archived Oct 20 2010 9:21AM  Nov 7 2010 7:58AM DLiu
1240129013170ACIS-SNONE4.0000003.9616001RXSJ194016.3+46325archived Oct 20 2010 9:21AM  Nov 7 2010 2:06PM DLiu
1240128913169ACIS-SNONE3.0000002.9652201RXSJ192607.1+50525archived Oct 20 2010 9:20AM  Nov 12 2010 4:16PM DLiu
1240128813168ACIS-SNONE3.0000002.9625141RXSJ190822.7+38510archived Oct 20 2010 9:20AM  Nov 12 2010 7:57PM DLiu
1240128713167ACIS-SNONE3.0000002.9600001RXSJ191016.9+39295archived Oct 20 2010 9:20AM  Nov 7 2010 6:52AM DLiu
1240128613166ACIS-SNONE3.0000002.7520001RXSJ193239.6+38251archived Oct 20 2010 9:20AM  Nov 4 2010 9:49PM DLiu
1240128513165ACIS-SNONE3.0000002.7584001RXSJ192630.6+41331archived Oct 20 2010 9:20AM  Nov 4 2010 10:50PM DLiu
1240128413164ACIS-SNONE2.0000002.0977001RXSJ194759.9+41311archived Oct 20 2010 9:20AM  Nov 14 2010 3:12AM DLiu
1240128313163ACIS-SNONE2.0000002.0975861RXSJ191438.6+50285archived Oct 20 2010 9:20AM  Nov 7 2010 1:05PM DLiu
1240128213161ACIS-SHETG30.00000030.074000EXO1745-248archived Oct 15 2010 12:44PM  Oct 24 2010 11:03AM DBhattacharyya
1250154013154ACIS-SNONE10.00000010.000000CrabNebulaarchived Oct 7 2010 11:57AM  Apr 28 2011 6:40AM NWeisskopf
1250153913153ACIS-SNONE10.00000010.000000CrabNebulaarchived Oct 7 2010 11:57AM  Apr 21 2011 11:25PM NWeisskopf
1250153813152ACIS-SNONE10.00000010.000000CrabNebulaarchived Oct 7 2010 11:57AM  Apr 16 2011 8:45AM NWeisskopf
1250153713151ACIS-SNONE10.00000010.000000CrabNebulaarchived Oct 7 2010 11:57AM  Apr 14 2011 2:32PM NWeisskopf
1250153613150ACIS-SNONE10.00000010.000000CrabNebulaarchived Oct 7 2010 11:57AM  Apr 13 2011 11:32PM NWeisskopf
1250153513149ACIS-SNONE15.00000015.459500XTEJ1810-197archived Oct 7 2010 10:30AM  Oct 25 2010 4:19AM DBernardini
1250153413148ACIS-SNONE30.00000030.009912SGR0418+5729archived Oct 6 2010 4:04PM  Nov 29 2010 6:10AM NRea
1250153313147ACIS-SNONE5.0000005.000000Crabarchived Oct 5 2010 4:26PM  Nov 28 2010 11:17AM Nferrigno
1250153213146ACIS-SNONE5.0000005.000000Crabarchived Oct 5 2010 4:26PM  Oct 28 2010 5:58PM Nferrigno
1150153113139ACIS-SNONE5.0000005.000000CrabNebulaarchived Sep 23 2010 3:29PM  Sep 28 2010 5:21AM NWeisskopf
1140128113122ACIS-SNONE10.00000010.026400ESO243-49HLX-1archived Sep 1 2010 9:49AM  Sep 6 2010 10:40PM DFarrell
1140114512314ACIS-SHETG6.0000006.000000CygX-1archived Jul 14 2010 10:31AM  Jul 24 2010 5:38PM NMcClintock
1140114412313ACIS-SHETG6.0000006.072000CygX-1archived Jul 14 2010 10:31AM  Jul 22 2010 4:39PM NMcClintock
1150137112312ACIS-SNONE30.00000030.009198SGR0418+5729archived Jul 12 2010 10:28AM  Jul 23 2010 3:16PM NRea
1140114112235ACIS-SHETG20.00000020.079600CirX-1archived Jun 29 2010 5:24PM  Jul 4 2010 5:22AM ND'A
0990093912234ACIS-INONE53.00000049.800438ChandraDeepFieldSarchived Jun 25 2010 4:49PM  Jul 22 2010 8:13PM 4Tananbaum
0990093912233ACIS-INONE35.00000036.043659ChandraDeepFieldSarchived Jun 25 2010 4:48PM  Jul 16 2010 10:52AM 4Tananbaum
0990093912232ACIS-INONE34.00000033.329777ChandraDeepFieldSarchived Jun 25 2010 4:45PM  Jul 18 2010 8:09PM 4Tananbaum
0990093912231ACIS-INONE25.00000025.047959ChandraDeepFieldSarchived Jun 23 2010 11:40AM  Jul 12 2010 3:49AM 4Tananbaum
0990093912230ACIS-INONE38.00000034.254918ChandraDeepFieldSarchived Jun 20 2010 2:29PM  Jul 11 2010 4:18AM 4Tananbaum
1150136912229ACIS-SNONE15.00000015.037309GRB100615Aarchived Jun 16 2010 3:07PM  Jun 21 2010 3:52AM NLevan
0990093912227ACIS-INONE55.00000055.043411ChandraDeepFieldSarchived Jun 10 2010 12:06PM  Jul 14 2010 9:28PM 4Tananbaum
0990093812223ACIS-INONE102.000000102.041441ChandraDeepFieldSarchived May 26 2010 4:55PM  Jun 13 2010 1:21AM 4Tananbaum
0990093812222ACIS-INONE31.00000031.049146ChandraDeepFieldSarchived May 26 2010 4:10PM  Jun 5 2010 3:09AM 4Tananbaum
1150136812221ACIS-SNONE10.00000010.065300XTEJ1810-197archived May 21 2010 11:36AM  Jun 7 2010 3:29AM DBernardini
0990093812220ACIS-INONE48.90000048.768154ChandraDeepFieldSarchived May 18 2010 8:29AM  Jun 18 2010 1:16PM 4Tananbaum
0990093812219ACIS-INONE34.20000034.106014ChandraDeepFieldSarchived May 18 2010 8:20AM  Jun 6 2010 4:49PM 4Tananbaum
0990093812218ACIS-INONE89.20000089.142158ChandraDeepFieldSarchived May 12 2010 5:03PM  Jun 11 2010 10:33AM 4Tananbaum
0990093612213ACIS-INONE62.10000062.098441ChandraDeepFieldSarchived Apr 28 2010 3:10PM  May 17 2010 2:55PM 4Tananbaum
1130028312203HRC-SLETG5.0000005.181632KTEriarchived Apr 9 2010 2:19PM  Apr 21 2010 11:03AM NDrake
0990093712138ACIS-INONE39.00000039.044418ChandraDeepFieldSarchived Mar 30 2010 8:19AM  Apr 18 2010 1:16PM 4Tananbaum
0990093712137ACIS-INONE94.00000094.010314ChandraDeepFieldSarchived Mar 30 2010 8:19AM  Apr 16 2010 9:10AM 4Tananbaum
0990093712135ACIS-INONE63.40000063.357678ChandraDeepFieldSarchived Mar 25 2010 3:35PM  Apr 6 2010 9:50AM 4Tananbaum
0990093712129ACIS-INONE78.20000078.160096ChandraDeepFieldSarchived Mar 17 2010 10:54AM  Apr 3 2010 3:40PM 4Tananbaum
0990093612128ACIS-INONE23.10000023.104259ChandraDeepFieldSarchived Mar 9 2010 4:02PM  Mar 27 2010 1:28PM 4Tananbaum
1140113812127ACIS-SHETG25.00000023.1677504U1608-52archived Mar 8 2010 4:25PM  Mar 15 2010 4:46AM NOzel
0990093612123ACIS-INONE25.10000025.118041ChandraDeepFieldSarchived Mar 4 2010 3:45PM  Mar 21 2010 8:23AM 4Tananbaum
1130027712102HRC-SLETG25.00000023.244182UScorpiiarchived Jan 28 2010 12:11PM  Feb 14 2010 11:56AM NOrio
1130027612101HRC-SLETG5.0000005.158825KTEriarchived Jan 26 2010 9:26AM  Feb 6 2010 6:43AM NDrake
1130027512100HRC-SLETG5.0000005.181375KTEriarchived Jan 26 2010 9:26AM  Jan 31 2010 10:43PM NDrake
1130027412097HRC-SLETG15.00000015.183582KTEriarchived Jan 20 2010 12:33PM  Jan 23 2010 10:01PM NNess
1170231712087ACIS-SNONE3.0000003.061700Q0957+561archived Dec 22 2009 2:14PM  Jun 23 2010 11:29PM NGoicoechea
1170231612086ACIS-SNONE3.0000003.062981Q0957+561archived Dec 22 2009 2:13PM  Jun 10 2010 10:14AM NGoicoechea
1170231512085ACIS-SNONE3.0000003.061700Q0957+561archived Dec 22 2009 2:13PM  May 25 2010 11:08PM NGoicoechea
1170231412084ACIS-SNONE3.0000003.182400Q0957+561archived Dec 22 2009 2:13PM  May 15 2010 4:53AM NGoicoechea
1170231312083ACIS-SNONE3.0000003.151800Q0957+561archived Dec 22 2009 2:12PM  Apr 27 2010 1:21PM NGoicoechea
1170231212082ACIS-SNONE3.0000003.182400Q0957+561archived Dec 22 2009 2:12PM  Apr 13 2010 1:14PM NGoicoechea
1170231112081ACIS-SNONE3.0000003.170500Q0957+561archived Dec 22 2009 2:11PM  Mar 29 2010 9:43PM NGoicoechea
1170231012080ACIS-SNONE3.0000003.126300Q0957+561archived Dec 22 2009 2:11PM  Mar 15 2010 12:00PM NGoicoechea
1170230912079ACIS-SNONE3.0000003.150100Q0957+561archived Dec 22 2009 2:11PM  Mar 3 2010 2:58PM NGoicoechea
1170230812078ACIS-SNONE3.0000003.182400Q0957+561archived Dec 22 2009 2:10PM  Feb 18 2010 6:43AM NGoicoechea
1170230712077ACIS-SNONE3.0000003.185800Q0957+561archived Dec 22 2009 2:10PM  Feb 1 2010 12:50AM NGoicoechea
1170230612076ACIS-SNONE3.0000003.060000Q0957+561archived Dec 22 2009 1:57PM  Jan 17 2010 12:56PM NGoicoechea
1040113712067ACIS-SHETG11.00000011.0812501A0535+262archived Dec 15 2009 1:14PM  Dec 31 2009 2:19AM DReynolds
1040113712066ACIS-SHETG9.0000008.9172501A0535+262archived Dec 10 2009 2:59AM  Dec 28 2009 11:08AM DReynolds
0990093612055ACIS-INONE81.80000081.749978ChandraDeepFieldSarchived Nov 24 2009 3:21PM  May 15 2010 5:35PM 4Tananbaum
0990093912054ACIS-INONE62.00000061.810778ChandraDeepFieldSarchived Nov 24 2009 3:21PM  Jul 9 2010 12:02PM 4Tananbaum
0990093912053ACIS-INONE75.00000069.009060ChandraDeepFieldSarchived Nov 24 2009 3:21PM  Jul 5 2010 3:30AM 4Tananbaum
0990093912052ACIS-INONE112.600000111.875500ChandraDeepFieldSarchived Nov 24 2009 3:21PM  Jun 15 2010 4:32PM 4Tananbaum
0990093812051ACIS-INONE58.00000058.044247ChandraDeepFieldSarchived Nov 24 2009 3:21PM  Jun 10 2010 11:57AM 4Tananbaum
0990093812050ACIS-INONE30.00000030.048259ChandraDeepFieldSarchived Nov 24 2009 3:21PM  Jun 3 2010 7:03AM 4Tananbaum
0990093812049ACIS-INONE88.00000088.088925ChandraDeepFieldSarchived Nov 24 2009 3:21PM  May 28 2010 7:18PM 4Tananbaum
0990093712048ACIS-INONE140.000000139.932947ChandraDeepFieldSarchived Nov 24 2009 3:21PM  May 23 2010 7:26AM 4Tananbaum
0990093712047ACIS-INONE10.30000010.276459ChandraDeepFieldSarchived Nov 24 2009 3:21PM  Apr 12 2010 1:47PM 4Tananbaum
0990093712046ACIS-INONE79.00000079.056119ChandraDeepFieldSarchived Nov 24 2009 3:21PM  Apr 8 2010 8:31AM 4Tananbaum
0990093712045ACIS-INONE101.000000101.037949ChandraDeepFieldSarchived Nov 24 2009 3:21PM  Mar 28 2010 4:58PM 4Tananbaum
0990093612044ACIS-INONE100.800000100.842837ChandraDeepFieldSarchived Nov 24 2009 3:21PM  Mar 23 2010 11:55AM 4Tananbaum
0990093612043ACIS-INONE131.300000131.294013ChandraDeepFieldSarchived Nov 24 2009 3:21PM  Mar 18 2010 1:58AM 4Tananbaum
1020065612009ACIS-SNONE25.00000024.473600V838Monarchived Oct 13 2009 10:58AM  Jan 12 2010 8:44AM NKastner
1040112511803HRC-INONE10.00000010.156982ESO243-49HLX-1archived Aug 10 2009 5:46PM  Aug 17 2009 12:41PM NFarrell
1040112411802ACIS-SNONE5.0000005.035200NGC6440archived Aug 4 2009 6:03PM  Aug 10 2009 8:26AM NHeinke
1050117410929ACIS-INONE20.00000020.134400PSRJ1622-4950archived Jul 8 2009 9:03AM  Jul 10 2009 7:43AM 3Rea
1070197310921ACIS-SNONE5.0000005.0464002XMMJ130200.1+27465archived Jun 3 2009 12:08PM  Jun 27 2009 3:28AM NWatson
1040106610919HRC-INONE1.0000001.175675ESO243-49HLX-1archived May 29 2009 1:38PM  Jul 4 2009 2:15PM NFarrell
1040106510907ACIS-SNONE20.00000018.448100GROJ1655-40archived Apr 17 2009 5:40PM  Jun 8 2009 2:46AM NGallo
0920056910845ACIS-SNONE40.00000040.134400ZCMaarchived Dec 18 2008 11:19AM  Dec 28 2008 10:48PM NStelzer
0920056810826HRC-INONE5.0000004.97842551Pegarchived Nov 17 2008 8:51AM  Dec 6 2008 12:52PM NSchmitt
0920056810825ACIS-SNONE5.0000004.98240051Pegarchived Nov 17 2008 8:45AM  Dec 6 2008 11:21AM NSchmitt
0940105110574HRC-INONE5.0000005.162669XTEJ1701-407archived Aug 18 2008 3:29PM  Aug 26 2008 8:24PM DKaplan
0950115210573ACIS-SNONE10.00000010.152500GRB080307archived Aug 14 2008 5:07PM  Sep 22 2008 8:36AM NPage
0940105010571HRC-INONE1.0000001.183875VPuppisarchived Aug 7 2008 2:56PM  Sep 1 2008 1:40AM NMaccarone
094009349883ACIS-SNONE10.00000010.198400XMMUJ005510.7-37385archived Jun 25 2008 2:22AM  Jul 8 2008 9:26PM NKong
094009339882ACIS-SNONE30.00000030.180000AXJ1754.2-2754archived Jun 24 2008 3:23PM  Jul 15 2008 12:30AM DKeek
095010189862ACIS-SNONE30.00000030.147200GRB080503archived May 16 2008 4:13PM  May 25 2008 6:28PM NButler
095010179853ACIS-SNONE30.00000030.175400GRB080503archived May 5 2008 9:16PM  May 7 2008 7:35PM NButler
094009329850HRC-INONE2.0000002.186069XTEJ1719-291archived Apr 15 2008 8:53AM  Apr 27 2008 6:34PM DSala
097017719814ACIS-SNONE10.0000009.907200SDSSJ0952+2143archived Jan 23 2008 8:44AM  Feb 5 2008 4:43PM NKomossa
094009319805ACIS-SNONE5.0000005.175000M81archived Dec 19 2007 2:43PM  Dec 21 2007 6:54PM DJonker
095010149799ACIS-SNONE21.50000021.569800SN2007onarchived Dec 12 2007 3:41PM  Dec 27 2007 1:35AM DRoelofs
095010149798ACIS-SNONE18.50000018.544200SN2007onarchived Dec 5 2007 3:21PM  Dec 24 2007 11:15AM DRoelofs
092005269769ACIS-INONE30.00000030.150559NGC2264archived Nov 9 2007 4:15PM  Mar 28 2008 3:02PM NMicela
092005269768ACIS-INONE30.00000028.154200NGC2264archived Nov 9 2007 4:08PM  Mar 12 2008 6:10PM NMicela
081000719763ACIS-SNONE10.00000010.179200Comet17P/Holmesarchived Oct 29 2007 1:32PM  Oct 31 2007 4:21PM NDennerl
081000719762ACIS-SNONE10.00000010.188800Comet17P/Holmesarchived Oct 29 2007 1:32PM  Oct 31 2007 1:26PM NDennerl
081000719755ACIS-SNONE10.00000010.137600Comet17P/Holmesarchived Oct 26 2007 4:43PM  Oct 31 2007 10:31AM NDennerl
089007379718ACIS-INONE51.00000050.030737ChandraDeepFieldSarchived Sep 19 2007 3:00PM  Oct 3 2007 2:12PM NTananbaum
089007379596ACIS-INONE115.400000113.372872ChandraDeepFieldSarchived Sep 10 2007 3:32PM  Nov 4 2007 4:30AM NTananbaum
089007379593ACIS-INONE48.00000047.045600ChandraDeepFieldSarchived Sep 5 2007 12:11PM  Sep 22 2007 8:49PM NTananbaum
084009289584HRC-INONE2.0000002.184531M15archived Aug 27 2007 11:51AM  Sep 5 2007 3:23PM NHeinke
085010099579ACIS-INONE20.00000019.709759SN2007grarchived Aug 21 2007 1:16PM  Aug 29 2007 1:52AM NSoderberg
089007379578ACIS-INONE40.00000039.084800ChandraDeepFieldSarchived Aug 20 2007 4:20PM  Oct 30 2007 10:53PM NTananbaum
089007379575ACIS-INONE112.400000110.133372ChandraDeepFieldSarchived Aug 20 2007 4:18PM  Oct 27 2007 6:09AM NTananbaum
089007378597ACIS-INONE61.00000060.068618ChandraDeepFieldSarchived Aug 7 2007 3:31PM  Oct 17 2007 7:23AM NTananbaum
089007378596ACIS-INONE118.000000116.640477ChandraDeepFieldSarchived Aug 7 2007 3:31PM  Oct 24 2007 1:46PM NTananbaum
089007378595ACIS-INONE118.000000116.950436ChandraDeepFieldSarchived Aug 7 2007 3:31PM  Oct 19 2007 2:35PM NTananbaum
089007378594ACIS-INONE151.200000143.272414ChandraDeepFieldSarchived Aug 7 2007 3:31PM  Nov 1 2007 12:10PM NTananbaum
089007378593ACIS-INONE51.00000050.145559ChandraDeepFieldSarchived Aug 7 2007 3:31PM  Oct 6 2007 2:22AM NTananbaum
089007378592ACIS-INONE88.00000087.785596ChandraDeepFieldSarchived Aug 7 2007 3:31PM  Oct 22 2007 12:36PM NTananbaum
089007378591ACIS-INONE46.00000046.034877ChandraDeepFieldSarchived Aug 7 2007 3:31PM  Sep 20 2007 5:41AM NTananbaum
084006918564ACIS-INONE11.20000011.152000SWIFTJ1756.9-2508archived Jun 19 2007 12:29PM  Jul 6 2007 1:44AM NDiSalvo
084006908562ACIS-SHETG10.00000010.152500SWIFTJ195509.6+2614archived Jun 12 2007 1:01PM  Jun 14 2007 6:17PM DKANBACH
084006898556HRC-INONE7.0000007.180382CirX-1archived Apr 27 2007 3:09PM  May 16 2007 9:11PM DJonker
084006888547HRC-INONE43.00000043.290108CirX-1archived Mar 30 2007 1:52PM  Apr 21 2007 5:32AM DJonker
086006498524ACIS-SNONE30.00000030.041600GRB070125archived Feb 22 2007 9:56AM  Mar 5 2007 9:49PM NFrail
085008228518ACIS-SNONE3.0000003.043200SN2005kdarchived Jan 30 2007 2:09PM  Mar 4 2007 2:54PM NPooley
087015838517ACIS-SNONE5.0000005.153200M87archived Jan 26 2007 3:19PM  Mar 22 2007 4:06AM NHarris
087015828516ACIS-SNONE5.0000005.159200M87archived Jan 26 2007 3:19PM  Mar 19 2007 10:38AM NHarris
087015818515ACIS-SNONE5.0000005.177600M87archived Jan 26 2007 3:19PM  Mar 14 2007 2:43PM NHarris
087015808514ACIS-SNONE5.0000004.929200M87archived Jan 26 2007 3:19PM  Mar 12 2007 11:52AM NHarris
087015798513ACIS-SNONE5.0000005.182800M87archived Jan 26 2007 3:19PM  Feb 24 2007 3:16AM NHarris
087015788512ACIS-SNONE5.0000005.185600M87archived Jan 26 2007 3:19PM  Feb 21 2007 11:58PM NHarris
087015778511ACIS-SNONE5.0000005.185600M87archived Jan 26 2007 3:19PM  Feb 18 2007 10:23PM NHarris
087015768510ACIS-SNONE5.0000005.183600M87archived Jan 26 2007 3:19PM  Feb 15 2007 9:37AM NHarris
085008218508HRC-INONE2.0000002.1599311RXSJ141256.0+79220archived Jan 19 2007 12:55PM  Feb 18 2007 6:05PM DRutledge
085008208506ACIS-SNONE20.00000020.182000PSRJ1647-4552archived Jan 8 2007 1:10PM  Feb 2 2007 7:26PM NWoods
075008178480HRC-INONE1.0000001.149025RBS1774(1RXSJ214303archived Nov 6 2006 2:27PM  Nov 26 2006 10:15PM DZane
072004608474ACIS-INONE10.0000009.753600LDN1415archived Oct 30 2006 11:32AM  Nov 18 2006 2:41AM NKastner
075008168473ACIS-SNONE30.00000030.124800SN2006gyarchived Oct 30 2006 11:20AM  Nov 14 2006 8:57PM NPooley
075008158457ACIS-SNONE10.0000009.961600SN2006jcarchived Oct 16 2006 12:14PM  Nov 4 2006 6:23AM NImmler
075008148455ACIS-SNONE15.00000015.186750PSRJ1647-4552archived Oct 12 2006 12:50PM  Oct 28 2006 7:19AM DKas
074006808273ACIS-INONE21.60000020.030359LSI+61303archived Sep 8 2006 3:29PM  Oct 25 2006 10:32PM NPerez-Torres
076006077373ACIS-SNONE7.0000007.184000XMMUJ132218.3-16424archived Jul 12 2006 5:56PM  Jul 31 2006 3:41AM NMiniutti
074005617335ACIS-SNONE10.0000009.376000PSRB1931+24archived May 5 2006 2:30PM  Jul 20 2006 3:01PM DRea
071000677334ACIS-SNONE4.0000004.182400Comet73P/Schwassmanarchived May 2 2006 2:32PM  May 23 2006 10:34AM NWolk
071000667333ACIS-SNONE4.0000004.182400Comet73P/Schwassmanarchived May 2 2006 2:32PM  May 23 2006 9:19AM NWolk
071000657332ACIS-SNONE4.0000004.185600Comet73P/Schwassmanarchived May 2 2006 2:32PM  May 23 2006 8:03AM NWolk
071000647331ACIS-SNONE4.0000004.185600Comet73P/Schwassmanarchived May 2 2006 2:32PM  May 23 2006 6:48AM NWolk
071000637330ACIS-SNONE4.0000004.105600Comet73P/Schwassmanarchived May 2 2006 2:32PM  May 23 2006 5:33AM NWolk
073001797298HRC-SLETG20.00000020.126132RSOpharchived Mar 3 2006 1:28PM  Jun 4 2006 12:25PM NStarrfield
073001787297HRC-SLETG10.0000009.505082RSOpharchived Mar 3 2006 1:28PM  Apr 20 2006 5:43PM NStarrfield
073001777296HRC-SLETG10.00000010.152882RSOpharchived Mar 3 2006 1:28PM  Mar 24 2006 12:40PM NStarrfield
073001727280ACIS-SHETG10.00000010.075000RSOpharchived Feb 14 2006 11:50AM  Feb 26 2006 3:36PM NStarrfield
075006937277ACIS-SNONE15.00000014.998400SN2005kearchived Feb 7 2006 9:31AM  Feb 19 2006 11:11AM NImmler
075006927276HRC-INONE1.0000001.112125IGRJ15359-5750archived Feb 6 2006 12:40PM  Mar 28 2006 4:54AM NIsrael
075006917275HRC-INONE1.0000001.122631IGRJ18048-1455archived Feb 6 2006 12:40PM  Mar 28 2006 4:10AM NIsrael
075006907274HRC-INONE1.0000001.097006IGRJ17513-2011archived Feb 6 2006 12:40PM  Mar 28 2006 3:40AM NIsrael
075006897273HRC-INONE1.0000001.095981IGRJ17488-3253archived Feb 6 2006 12:40PM  Mar 28 2006 3:07AM NIsrael
074005597272HRC-INONE2.0000002.135331SWIFTJ1626.6-5156archived Feb 2 2006 3:13PM  Feb 21 2006 6:28AM NHoman
074005587269ACIS-SNONE1.0000001.161600HD109962archived Jan 23 2006 1:03PM  Feb 2 2006 2:14PM NWalter
065006857241ACIS-SNONE50.00000050.179190SN2005gjarchived Nov 29 2005 4:53PM  Dec 11 2005 5:26PM NPooley
058005557225ACIS-INONE2.0000002.045959MACS1720.3+3536archived Nov 9 2005 3:10PM  Nov 27 2005 3:12AM NAllen
063001717186ACIS-SHETG50.00000050.155000RTCruarchived Oct 5 2005 2:19PM  Oct 19 2005 10:41AM NSokoloski
062003726375HRC-INONE5.0000005.150881AlphaCentauriarchived Aug 31 2005 11:31AM  Dec 17 2006 4:58AM NAYRES
062003716374HRC-INONE5.0000005.157031AlphaCentauriarchived Aug 31 2005 11:31AM  May 12 2006 6:31PM NAYRES
062003706373HRC-INONE5.0000005.187781AlphaCentauriarchived Aug 31 2005 11:31AM  Oct 21 2005 2:59AM NAYRES
064004726354ACIS-SNONE20.00000019.043960GRB050709archived Jul 19 2005 11:34AM  Jul 25 2005 9:03PM NFrail
064004706298HRC-INONE5.0000004.767531SAXJ1808.4-3658archived Jun 7 2005 9:38AM  Jun 20 2005 11:25PM NChakrabarty
064004696297ACIS-SHETG15.00000014.344000SAXJ1808.4-3658archived Jun 6 2005 3:27PM  Jun 12 2005 2:32AM NGalloway
065006036284ACIS-SNONE30.00000029.788040SN2005bxarchived May 6 2005 3:24PM  Jul 30 2005 11:11AM NFilippenko
067011806278ACIS-INONE3.5000003.638000IGRJ19473+4452archived Apr 20 2005 2:33PM  Jul 31 2005 9:32AM NSunyaev
067011796277ACIS-INONE3.5000003.759572IGRJ13091+1137archived Apr 20 2005 2:33PM  Jul 25 2005 10:25AM NSunyaev
067011786276ACIS-INONE3.5000003.260449IGRJ12391-1612archived Apr 20 2005 2:33PM  Jul 25 2005 11:45AM NSunyaev
067011776275ACIS-INONE3.5000003.260799IGRJ12026-5349archived Apr 20 2005 2:33PM  Jun 16 2005 6:10AM NSunyaev
067011766274ACIS-INONE3.5000003.676799IGRJ11085-5100archived Apr 20 2005 2:33PM  Jul 1 2005 3:58AM NSunyaev
067011756273ACIS-INONE3.5000003.707715IGRJ10252-6829archived Apr 20 2005 2:33PM  Jul 30 2005 9:24AM NSunyaev
067011746272ACIS-INONE3.5000003.257599IGRJ07563-4137archived Apr 20 2005 2:33PM  Jun 16 2005 4:46AM NSunyaev
067011736271ACIS-INONE3.5000003.459199IGRJ05007-7047archived Apr 20 2005 2:33PM  Jun 16 2005 3:25AM NSunyaev
065006016269ACIS-SNONE20.00000020.184090GRB050412archived Apr 14 2005 10:32AM  Apr 17 2005 9:43AM NBerger
064004686261ACIS-SNONE10.00000010.180800PSRJ1638-4725archived Mar 14 2005 10:52AM  May 4 2005 7:47PM NMcLaughlin
055006006260ACIS-SNONE10.00000010.140790GCRTJ1745-3009archived Mar 10 2005 3:52PM  May 1 2005 12:47AM DHyman
064004676259ACIS-SNONE5.0000005.169599HESSJ1826-148archived Mar 10 2005 3:26PM  Apr 13 2005 3:01AM NFunk
065005996251HRC-SNONE30.00000027.149430SGR1806-20archived Feb 22 2005 3:08PM  Apr 22 2005 7:03PM DKouveliotou
067011726227ACIS-SNONE10.00000010.323190NGC3690archived Feb 8 2005 11:54AM  Feb 14 2005 4:53AM NNandra
065005986224ACIS-INONE20.00000019.059190SGR1806-20archived Jan 27 2005 5:35PM  Feb 9 2005 7:25AM 1Fox
065005976207ACIS-SNONE30.00000029.100500SGR1806-20archived Jan 18 2005 10:13AM  Feb 8 2005 10:54PM 1Rea
062003636204ACIS-SNONE5.0000005.136400V1118Oriarchived Jan 18 2005 9:48AM  Jan 26 2005 3:24AM DAudard
064004476181ACIS-SNONE15.00000014.182800IGRJ00291+5934archived Dec 17 2004 5:25PM  Feb 6 2005 1:45PM NJonker
064004466180ACIS-SNONE10.0000009.894359IGRJ00291+5934archived Dec 17 2004 5:25PM  Jan 14 2005 12:11AM NJonker
064004456179ACIS-SNONE5.0000005.185200IGRJ00291+5934archived Dec 17 2004 5:25PM  Jan 1 2005 9:24PM NJonker
058005576172ACIS-INONE30.00000030.144270MACS1621.6+3810archived Nov 30 2004 9:54AM  Dec 25 2004 10:04PM NAllen
055005916129ACIS-INONE20.00000019.508000GRB040912archived Sep 13 2004 1:18PM  Sep 21 2004 11:18AM NRicker
055005906128ACIS-INONE20.00000018.168000GRB040912archived Sep 13 2004 1:18PM  Sep 15 2004 10:24PM NRicker
058005606112ACIS-INONE10.0000009.510799MACS1427.2+4407archived Aug 24 2004 2:41PM  Feb 12 2005 2:19AM NAllen
058005596111ACIS-INONE50.00000050.157877MACS0744.9+3927archived Aug 24 2004 2:41PM  Dec 3 2004 9:25PM NAllen
058005586110ACIS-INONE70.00000064.042810MACS1311.0-0311archived Aug 24 2004 2:41PM  Apr 20 2005 12:23AM NAllen
058005576109ACIS-INONE40.00000038.046250MACS1621.6+3810archived Aug 24 2004 2:41PM  Dec 11 2004 2:31PM NAllen
058005566108ACIS-INONE40.00000040.169750MACS0329.7-0212archived Aug 24 2004 2:41PM  Dec 6 2004 6:18AM NAllen
058005556107ACIS-INONE38.00000034.332410MACS1720.3+3536archived Aug 24 2004 2:41PM  Nov 22 2005 9:35PM NAllen
058005546106ACIS-INONE40.00000035.770890MACS0159.8-0849archived Aug 24 2004 2:41PM  Dec 4 2004 12:14PM NAllen
058005536105ACIS-INONE40.00000037.770350MACS0011.7-1523archived Aug 24 2004 2:41PM  Jun 28 2005 11:51AM NAllen
058005526104ACIS-INONE10.0000009.737000Abell2204archived Aug 24 2004 2:41PM  Sep 20 2004 11:42AM NAllen
058005516103ACIS-INONE10.00000010.406000PKS0745-191archived Aug 24 2004 2:41PM  Sep 24 2004 12:35AM NAllen
058005506102ACIS-INONE10.00000010.127000Abell478archived Aug 24 2004 2:41PM  Sep 13 2004 5:15PM NAllen
058005496101ACIS-INONE10.00000010.050190Abell2029archived Aug 24 2004 2:41PM  Dec 17 2004 3:50AM NAllen
055005856098ACIS-INONE5.0000004.707000HESSJ1303-631archived Aug 18 2004 9:57AM  Sep 25 2004 6:02PM DHalpern
055005085365ACIS-SNONE10.00000010.163000GRB040812archived Aug 13 2004 12:06PM  Aug 22 2004 10:12AM NKouveliotou
055005075364ACIS-SNONE10.00000010.175000GRB040812archived Aug 13 2004 12:06PM  Aug 17 2004 7:28AM NKouveliotou
056004125360ACIS-INONE5.0000005.174000CXOGCJ174540.0-2900archived Aug 3 2004 5:00PM  Aug 28 2004 12:21PM NBaganoff
041000525352HRC-INONE4.7000004.657000Moonarchived Jul 13 2004 3:11PM  Jul 28 2004 1:30AM NDrake
041000525351HRC-INONE5.6000005.471000Moonarchived Jul 13 2004 3:11PM  Jul 27 2004 11:13PM NDrake
041000525327HRC-INONE5.6000005.638000Moonarchived May 12 2004 1:59PM  Jun 2 2004 10:58AM NDrake
051000535326ACIS-SNONE3.3000003.471000Comet2001Q4(NEAT)archived May 3 2004 2:15PM  May 12 2004 8:58PM DLisse
051000535325ACIS-SNONE3.3000003.484000Comet2001Q4(NEAT)archived May 3 2004 2:14PM  May 12 2004 7:55PM DLisse
041000525324HRC-INONE5.6400005.772000Moonarchived Apr 23 2004 2:22PM  May 4 2004 7:00AM NDrake
051000535321ACIS-SNONE3.4000003.558000Comet2001Q4(NEAT)archived Apr 16 2004 2:05PM  May 12 2004 6:50PM DLisse
055005065314ACIS-SNONE30.00000030.156000GRB031203archived Mar 17 2004 5:29PM  Apr 18 2004 11:59AM DKouveliotou
041000525312HRC-INONE5.6000005.679000Moonarchived Mar 15 2004 2:11PM  Jun 2 2004 8:41AM NDrake
041000525311HRC-INONE5.6400005.521000Moonarchived Mar 15 2004 2:05PM  May 4 2004 4:36AM NDrake
052002985308ACIS-SNONE5.0000004.963000IRAS05436-0007archived Feb 19 2004 6:43PM  Mar 22 2004 12:35AM NKastner
052002975307ACIS-SNONE5.0000005.561000IRAS05436-0007archived Feb 19 2004 6:43PM  Mar 7 2004 1:41AM NKastner
055005055306ACIS-SNONE15.00000014.758000SN2001emarchived Feb 9 2004 3:39PM  Apr 4 2004 7:41PM NPooley
055005045305HRC-SLETG35.00000035.705000RXJ0720.4-3125archived Feb 9 2004 3:38PM  Feb 27 2004 4:53AM NVink
057010145302ACIS-SNONE30.00000031.121000NGC4395archived Jan 30 2004 8:22AM  Apr 11 2004 1:28AM NMoran
057010135301ACIS-SNONE30.00000029.730000NGC4395archived Jan 30 2004 8:22AM  Apr 10 2004 3:06AM NMoran
055005035298ACIS-SNONE25.00000021.848000GRB031203archived Jan 13 2004 11:16AM  Jan 22 2004 9:34PM NKulkarni
053001455293HRC-SLETG40.00000041.953000MiraABarchived Dec 19 2003 11:52AM  Jan 11 2004 2:09PM DKarovska
053001445292HRC-SLETG10.00000010.308000V4743Sgrarchived Dec 18 2003 5:07PM  Feb 28 2004 1:31AM NStarrfield
054003765291ACIS-SNONE10.00000010.137000PSRJ0737-3039archived Dec 18 2003 4:54PM  Jan 18 2004 7:56PM 1McLaughlin
045005005247HRC-INONE5.0000004.871000IGRJ16316-4028archived Oct 31 2003 1:24PM  Jan 18 2004 1:07PM DFoschini
045004995246ACIS-SNONE25.00000025.509000SN2003jdarchived Oct 31 2003 1:20PM  Nov 10 2003 7:08PM NWatson
045004985240HRC-INONE3.0000002.884000XTEJ1810-197archived Oct 9 2003 2:54PM  Nov 1 2003 3:26PM NIsrael
042002374455ACIS-SNONE20.00000019.898000EtaCararchived Aug 14 2003 12:21PM  Aug 28 2003 5:53PM SCorcoran
045004154454HRC-INONE3.0000002.833000XTEJ1810-197archived Aug 12 2003 2:22PM  Aug 27 2003 10:43PM NGotthelf
045004134449ACIS-SNONE20.00000018.435000SN2002icarchived Aug 4 2003 2:52PM  Aug 11 2003 9:40PM DHughes
045004124443ACIS-SNONE25.00000025.125000SGR1806-20archived Jul 21 2003 6:54PM  Aug 3 2003 12:13PM DWoods
044003244439ACIS-SHETG10.0000009.987000XTEJ1814-338archived Jun 6 2003 4:18PM  Jun 20 2003 2:12AM DChakrabarty
048003754438ACIS-SNONE30.00000029.136000RCS0439.6-2905archived May 12 2003 2:31PM  Jun 6 2003 6:17AM DBautz
044003234434ACIS-SNONE47.00000047.051000IGRJ16358-4726archived Apr 10 2003 4:23PM  Apr 21 2003 3:49AM DKouveliotou
045004114432ACIS-SLETG100.00000098.100000GRB030328archived Mar 28 2003 10:14AM  Mar 29 2003 3:05AM NRicker
044003224426HRC-SNONE3.0000002.824000XTEJ1807-294archived Feb 27 2003 3:35PM  Mar 10 2003 8:34AM DMARKWARDT
045004104425ACIS-SNONE40.00000040.172000GRB030226archived Feb 26 2003 3:15PM  Feb 27 2003 5:14PM NPedersen
044003214424ACIS-SNONE10.00000010.687000XTEJ1908+094archived Feb 20 2003 2:41PM  May 14 2003 1:51AM DJonker
044003204423ACIS-SNONE5.0000005.150000XTEJ1908+094archived Feb 20 2003 2:41PM  Apr 19 2003 3:14PM DJonker
044003194422ACIS-SNONE5.0000005.212000XTEJ1908+094archived Feb 20 2003 2:41PM  Mar 24 2003 12:07AM DJonker
044003184420ACIS-SHETG75.00000076.220000GX339-4archived Feb 12 2003 1:59PM  Mar 17 2003 8:05PM DMiller
045004094417ACIS-SNONE30.00000030.415000SN2003Larchived Jan 30 2003 7:05PM  Feb 10 2003 3:59AM NKulkarni
031000384410HRC-INONE1.0000001.120000EARTHarchived Dec 4 2002 4:43PM  Feb 7 2003 1:23AM DGladstone
035004084409ACIS-SNONE30.00000030.431000GRB021004archived Nov 17 2002 12:28PM  Nov 25 2002 5:51PM NSako
035004074405ACIS-SNONE10.00000010.115000SN2002HIarchived Nov 7 2002 8:46PM  Dec 10 2002 5:45PM NLewin
035004064404ACIS-SNONE30.00000030.335000SN2002HHarchived Nov 7 2002 8:42PM  Nov 25 2002 8:58AM NLewin
035004054381ACIS-SHETG80.00000088.130000GRB021004archived Oct 4 2002 12:41PM  Oct 5 2002 8:58AM NHarrison
035004044364ACIS-SHETG80.00000078.122000GRB020813archived Aug 13 2002 5:56AM  Aug 13 2002 11:46PM NRicker
036003304360ACIS-INONE5.0000004.969000M31archived Aug 2 2002 9:52AM  Aug 11 2002 6:15PM NPrimini
034003164358ACIS-INONE5.0000004.979000TEVJ2032+4130archived Aug 1 2002 5:35PM  Aug 11 2002 8:07PM DButt
034003154285ACIS-SNONE5.0000004.687000V4641SGRarchived Jul 19 2002 11:42AM  Aug 5 2002 4:16AM DRupen
034002703724ACIS-SHETG30.00000026.400000CYGX-1archived Jul 15 2002 12:33PM  Jul 30 2002 5:42PM NFeng
034002683672ACIS-SNONE20.00000018.255000XTEJ1550-564archived May 29 2002 9:42AM  Jun 19 2002 9:17AM DCorbel
034002673671ACIS-SNONE5.0000005.5380001E1740.7-2942archived May 29 2002 9:33AM  Aug 17 2002 1:24PM DHeindl
034002663670ACIS-SHETG10.00000010.1400001E1740.7-2942archived May 29 2002 9:33AM  Jun 13 2002 7:29PM DHeindl
034002653661ACIS-SLETG20.00000017.961000XTEJ0929-314archived May 10 2002 3:51PM  May 15 2002 12:43AM DChakrabarty
035002983496ACIS-SNONE25.00000024.188000SN2001IGarchived Apr 30 2002 12:59PM  Jun 11 2002 6:20AM NSchlegel
035002973495ACIS-SNONE25.00000023.734000SN2001IGarchived Apr 30 2002 12:59PM  May 21 2002 11:53PM NSchlegel
035002963494ACIS-SNONE15.00000014.755000XRF020427archived Apr 29 2002 3:42PM  May 14 2002 3:55AM NFox
035002953493ACIS-SNONE15.00000013.916000XRF020427archived Apr 29 2002 3:42PM  May 6 2002 5:46AM NFox
034002473492ACIS-SNONE5.0000005.231000RXJ170930.2-263927archived Apr 22 2002 3:15PM  Apr 23 2002 9:58PM DJonker
034002563490ACIS-SNONE7.0000007.648000AQLX-1archived Apr 5 2002 12:13PM  Sep 3 2002 4:27PM DRutledge
034002553489ACIS-SNONE7.0000007.858000AQLX-1archived Apr 5 2002 12:13PM  Aug 18 2002 8:19AM DRutledge
034002543488ACIS-SNONE7.0000007.172000AQLX-1archived Apr 5 2002 12:13PM  Jul 22 2002 9:01PM DRutledge
034002533487ACIS-SNONE7.0000006.549000AQLX-1archived Apr 5 2002 12:13PM  Jul 5 2002 3:45PM DRutledge
034002523486ACIS-SNONE7.0000007.151000AQLX-1archived Apr 5 2002 12:13PM  Jun 11 2002 3:50AM DRutledge
034002513485ACIS-SNONE7.0000007.672000AQLX-1archived Apr 5 2002 12:13PM  May 20 2002 7:41AM DRutledge
034002503484ACIS-SNONE7.0000007.160000AQLX-1archived Apr 5 2002 12:13PM  May 4 2002 11:04PM DRutledge
034002493483HRC-SNONE3.0000002.976000XTEJ1751-305archived Apr 5 2002 10:44AM  Apr 10 2002 4:31PM DMARKWARDT
034002483481ACIS-SNONE1.0000001.133000XTEJ1908+094archived Apr 3 2002 2:33PM  Apr 15 2002 5:39AM NRupen
035002943477ACIS-SNONE20.00000020.057000GRB020321archived Mar 25 2002 11:28AM  Mar 31 2002 2:13AM NFox
034002463475ACIS-SNONE5.0000005.965000RXJ170930.2-263927archived Mar 19 2002 3:24PM  Apr 10 2002 5:49PM DJonker
034002393464ACIS-SNONE5.0000005.147000RXJ170930.2-263927archived Mar 11 2002 9:44AM  Apr 1 2002 12:43AM DJonker
034002383463ACIS-SNONE8.4770007.468038RXJ170930.2-263927archived Mar 11 2002 9:44AM  Mar 18 2002 11:46AM DJonker
034002373462ACIS-SNONE15.00000014.210000RXJ170930.2-263927archived Mar 11 2002 9:44AM  Mar 12 2002 1:52PM DJonker
033000903455ACIS-SHETG35.00000034.457000GKPERarchived Mar 6 2002 5:15PM  Apr 9 2002 3:06PM DMauche
033000893454ACIS-SHETG35.00000032.102000GKPERarchived Mar 6 2002 5:15PM  Mar 27 2002 9:49AM DMauche
031000343453ACIS-SNONE12.00000011.964000Comet2002C1archived Mar 6 2002 2:20PM  Apr 15 2002 11:15PM DDennerl
035002923449ACIS-SNONE3.0000002.662000SGR1900+14archived Feb 27 2002 4:34PM  Mar 11 2002 11:03AM DWoods
034002363448ACIS-SNONE30.00000027.457000XTEJ1550-564archived Feb 14 2002 12:00PM  Mar 11 2002 3:16PM DCorbel
031000343447ACIS-SNONE12.00000011.718000Comet2002C1archived Feb 14 2002 9:25AM  Apr 15 2002 1:52AM DDennerl
035002913441ACIS-INONE15.00000014.672000XRF011130archived Feb 4 2002 5:21PM  Feb 20 2002 10:18AM NRicker
035002873437ACIS-INONE10.00000010.064000GRB020127archived Jan 30 2002 1:31PM  Feb 11 2002 11:17AM NFox
035002863436ACIS-INONE10.0000009.968000GRB020127archived Jan 30 2002 1:31PM  Jan 31 2002 10:37PM NFox
033000873434ACIS-SNONE5.0000005.629000IMNORMAEarchived Jan 23 2002 12:58PM  Feb 4 2002 6:01PM NStarrfield
037006123419ACIS-SNONE100.00000097.944000MGJ0414+0534archived Dec 7 2001 4:55PM  Jan 9 2002 12:00AM DChartas
031000323412ACIS-SNONE20.00000020.122000XRF011030archived Nov 15 2001 3:17PM  Nov 29 2001 11:09AM DHarrison
031000313411ACIS-SNONE50.00000047.209000XRF011030archived Nov 9 2001 12:48AM  Nov 9 2001 5:44PM NHarrison
024002343407ACIS-SHETG30.00000030.070000CYGX-1archived Oct 19 2001 10:35AM  Oct 28 2001 4:33PM DCui
025002853399HRC-SLETG9.5000009.318000RXJ1856.5-3754archived Oct 1 2001 9:20AM  Oct 15 2001 11:59AM NTananbaum
027006083395ACIS-SNONE30.00000028.777000MGJ0414+0534archived Sep 27 2001 10:49AM  Nov 9 2001 8:34AM DChartas
025002853382HRC-SLETG100.500000101.926000RXJ1856.5-3754archived Sep 18 2001 4:46PM  Oct 8 2001 8:31AM NTananbaum
025002853381HRC-SLETG170.000000171.073000RXJ1856.5-3754archived Sep 18 2001 4:46PM  Oct 12 2001 7:31PM NTananbaum
025002853380HRC-SLETG170.000000167.446000RXJ1856.5-3754archived Sep 18 2001 4:43PM  Oct 10 2001 5:18AM NTananbaum
024002333360ACIS-SNONE2.5000002.641000NGC6440archived Aug 15 2001 12:28PM  Aug 18 2001 8:23PM Nin'tZand
027006073359ACIS-SNONE6.0000005.760000QSOJ0836+0054archived Aug 10 2001 4:26PM  Jan 29 2002 12:02PM NBrandt
027006063358ACIS-SNONE8.0000008.262000QSOJ1306+0356archived Aug 10 2001 4:26PM  Jan 29 2002 6:28AM NBrandt
027006053357ACIS-SNONE8.0000008.057000QSOJ1030+0524archived Aug 10 2001 2:46PM  Jan 29 2002 9:11AM NBrandt
023000672514ACIS-SNONE10.00000010.179000WZSGEarchived Jul 31 2001 1:15PM  Sep 19 2001 1:56AM NKuulkers
023000662513ACIS-SNONE10.00000012.075000WZSGEarchived Jul 31 2001 1:15PM  Aug 22 2001 8:41AM NKuulkers
023000652512ACIS-SNONE5.0000004.910000WZSGEarchived Jul 31 2001 1:15PM  Aug 7 2001 5:47PM NKuulkers
023000612508ACIS-SNONE5.0000005.159000WZSGEarchived Jul 24 2001 6:25PM  Jul 29 2001 4:49PM NWheatley
023000592506HRC-SLETG20.00000019.984000WZSGEarchived Jul 24 2001 6:14PM  Aug 18 2001 8:07AM NWheatley
023000582505HRC-SLETG20.00000018.760000WZSGEarchived Jul 24 2001 6:14PM  Aug 6 2001 7:53PM NWheatley
023000572504HRC-SLETG20.00000019.950000WZSGEarchived Jul 24 2001 6:14PM  Jul 27 2001 2:44AM NWheatley
023000562492ACIS-SNONE20.00000019.885000CIAQLarchived Jul 6 2001 4:17PM  Aug 1 2001 12:52PM DGreiner
023000542465ACIS-SNONE2.0000002.149000CIAQLarchived May 9 2001 12:29PM  Jun 1 2001 8:41PM DGreiner
025002002459ACIS-SNONE20.00000018.896000PSRJ1907+0919archived Apr 19 2001 11:22AM  Apr 30 2001 11:27PM NKouveliotou
025001992458ACIS-SNONE20.00000020.835000SGR1900+14archived Apr 18 2001 7:19PM  Apr 22 2001 4:58AM NKulkarni
027003932454ACIS-SNONE5.0000004.500000CIRCINUSGALAXYarchived Apr 13 2001 1:53PM  May 2 2001 4:20PM NMatt
024001642430HRC-INONE10.0000009.889000GRS1758-258archived Mar 9 2001 12:43PM  Mar 24 2001 7:43AM DHeindl
024001632429ACIS-SHETG30.00000030.320000GRS1758-258archived Mar 9 2001 12:43PM  Mar 24 2001 10:58AM DHeindl
024001622428ACIS-SNONE20.00000020.400000KS1731-260archived Mar 7 2001 3:25PM  Mar 27 2001 12:34AM DWijnands
028001782427ACIS-SNONE20.00000018.094000PKS0745-191archived Mar 7 2001 10:46AM  Jun 16 2001 5:50AM DFabian
025001972424ACIS-SNONE30.00000029.923000GRB010222archived Feb 22 2001 10:36AM  Feb 22 2001 10:28PM DPiro
024001612415ACIS-SHETG30.00000030.146000CYGNUSX-1archived Dec 16 2000 3:51PM  Jan 4 2001 6:20AM DMiller
029000662409ACIS-INONE69.00000069.895000ChandraDeepFieldSarchived Dec 5 2000 4:47PM  Dec 19 2000 4:12AM NGIACCONI
029000662406ACIS-INONE31.00000030.079000ChandraDeepFieldSarchived Dec 1 2000 2:25PM  Dec 10 2000 11:51PM NGIACCONI
022001252338ACIS-SHETG25.00000024.838000WR140archived Oct 27 2000 10:51AM  May 8 2001 8:01PM DPollock
022001242337ACIS-SHETG50.00000046.124000WR140archived Oct 27 2000 10:51AM  Dec 29 2000 10:32AM DPollock
013000532336ACIS-SHETG20.00000019.222000ZANDROMEDAEarchived Oct 26 2000 3:36PM  Nov 13 2000 3:19PM DCharles
029000662313ACIS-INONE132.000000132.115000ChandraDeepFieldSarchived Sep 22 2000 10:04AM  Dec 21 2000 2:28AM NGIACCONI
029000662312ACIS-INONE136.000000125.323000ChandraDeepFieldSarchived Sep 22 2000 10:04AM  Dec 13 2000 3:47AM NGIACCONI
029000662239ACIS-INONE132.000000132.469000ChandraDeepFieldSarchived Aug 28 2000 4:08PM  Dec 23 2000 5:49PM NGIACCONI
014001121846ACIS-SNONE5.0000004.630000XTEJ1550-564archived Aug 7 2000 3:27PM  Sep 11 2000 5:10AM DTomsick
014001111845ACIS-SNONE5.0000005.164000XTEJ1550-564archived Aug 7 2000 3:27PM  Aug 21 2000 9:08AM DTomsick
017002661715HRC-SLETG20.00000019.839000MRK421archived May 8 2000 5:01PM  May 29 2000 5:53PM NFruscione
017002651714ACIS-SHETG20.00000019.830000MRK421archived May 8 2000 5:01PM  May 29 2000 11:57AM NFruscione
013000411706ACIS-SHETG60.00000059.881000EXHYAarchived Apr 13 2000 3:23PM  May 18 2000 9:59AM DHowell
014001101701ACIS-SLETG30.00000027.830000XTEJ1118+480archived Apr 7 2000 3:32PM  Apr 18 2000 6:36PM DMcClintock
01700202442ACIS-SNONE5.0000004.976000NGC526Aarchived Mar 16 2000 9:26AM  Apr 23 2000 6:54AM SWilson
01400093426ACIS-SHETG20.00000018.318000CYGX-3archived Feb 16 2000 2:09PM  Apr 6 2000 8:17PM NMcCollough
01400092425ACIS-SHETG20.00000021.654000CYGX-3archived Feb 16 2000 2:09PM  Apr 4 2000 2:05PM NMcCollough
01300037327ACIS-SNONE5.0000004.9470002MASSJ06285693+7202archived Jan 20 2000 10:10AM  Feb 8 2000 4:18PM DDiStefano
01500093364HRC-INONE50.00000048.159000PSRB0833-45archived Jan 19 2000 11:30AM  Feb 21 2000 2:11AM NHelfand
01300037327ACIS-SNONE5.0000004.9470002MASSJ06285693+7202archived Jan 19 2000 11:30AM  Feb 8 2000 4:18PM DDiStefano
015704701520ACIS-SNONE25.00000024.035000NGC3184archived Jan 19 2000 11:21AM  Feb 3 2000 11:00AM 3Schlegel
011000111465HRC-SLETG23.15000023.418000JUPITERarchived Oct 20 1999 1:31PM  Nov 26 1999 8:07PM 3WAITE
011000111464HRC-SLETG14.76000014.778000JUPITERarchived Oct 20 1999 1:30PM  Nov 26 1999 2:35PM 3WAITE
011000101463ACIS-SNONE22.60000022.364000JUPITERarchived Oct 20 1999 1:29PM  Nov 26 1999 2:10AM 3WAITE

Canceled DDT Observations
CycleSequence NumberObsIDInstrumentGratingApproved Exposure TimeTargetStatusPI Name
2240229124934ACIS-SHETG40.000000CenX-4canceledin'tZand
2170425324647ACIS-SNONE30.000000ESO253-G003canceledPayne
2170425224646ACIS-SNONE30.000000ESO253-G003canceledPayne
2120134623150HRC-INONE5.000000BetelgeusecanceledKashyap
2120134523149HRC-INONE5.000000BetelgeusecanceledKashyap
2040211622135ACIS-SNONE15.000000ZTF18abfzgplcanceledOfek
1720108518820ACIS-SHETG30.000000CapellacanceledPetre
1720108518819ACIS-SHETG30.000000CapellacanceledPetre
1540168717560ACIS-SNONE20.000000CXOJ122518.6+144545canceledHeida
1320082914409ACIS-SNONE8.00000055CnccanceledWheatley
1240129613245HRC-INONE1.000000MAXIJ1659-152canceledJonker
0990093912311ACIS-INONE18.700000ChandraDeepField-ScanceledTananbaum
0990093612214ACIS-INONE40.000000ChandraDeepField-ScanceledTananbaum
089007379577ACIS-INONE30.000000ChandraDeepField-ScanceledTananbaum
089007379576ACIS-INONE2.000000ChandraDeepField-ScanceledTananbaum
072004618475ACIS-INONE10.000000L1415EXorcanceledKastner
073001827301ACIS-SHETG15.000000RSOphcanceledStarrfield
073001817300ACIS-SHETG15.000000RSOphcanceledStarrfield
073001807299HRC-SLETG20.000000RSOphcanceledStarrfield
065006847192ACIS-SNONE20.000000GRB051022canceledRicker
062003656206ACIS-SNONE8.333333V1118OricanceledAudard
062003646205ACIS-SNONE8.333333V1118OricanceledAudard
041000525328HRC-INONE2.500000MooncanceledDrake
041000525313HRC-INONE4.700000MooncanceledDrake
045004144450ACIS-SNONE20.000000SN2002iccanceledHughes
034002693723ACIS-SNONE30.000000MACHO-99-BLG-22canceledReynolds
035002993497ACIS-SNONE25.000000SN2001IGcanceledSchlegel
034002453470ACIS-SNONE10.000000RXJ170930.2-263927canceledJonker
034002443469ACIS-SNONE10.000000RXJ170930.2-263927canceledJonker
034002433468ACIS-SNONE10.000000RXJ170930.2-263927canceledJonker
034002423467ACIS-SNONE5.000000RXJ170930.2-263927canceledJonker
034002413466ACIS-SNONE5.000000RXJ170930.2-263927canceledJonker
034002403465ACIS-SNONE5.000000RXJ170930.2-263927canceledJonker
031000333446ACIS-SNONE8.000000C/2002C1canceledDennerl
035002903440ACIS-SNONE25.000000SN2002APcanceledSchlegel
035002893439ACIS-SNONE25.000000SN2002APcanceledSchlegel
035002883438ACIS-SNONE25.000000SN2002APcanceledSchlegel
033000883435ACIS-SNONE25.000000IMNORMAEcanceledStarrfield
037006143421ACIS-SNONE30.000000MGJ0414+0534canceledChartas
037006133420ACIS-SNONE30.000000MGJ0414+0534canceledChartas
027006113398ACIS-SNONE30.000000MGJ0414+0534canceledChartas
027006103397ACIS-SNONE30.000000MGJ0414+0534canceledChartas
027006093396ACIS-SNONE30.000000MGJ0414+0534canceledChartas
011000273379ACIS-SNONE9.000000COMET19P/BORRELLYcanceledDennerl
011000273378ACIS-SNONE9.000000COMET19P/BORRELLYcanceledDennerl
011000273377ACIS-SNONE9.000000COMET19P/BORRELLYcanceledDennerl
011000272517ACIS-SNONE9.000000COMET19P/BORRELLYcanceledDennerl
023000642511ACIS-SNONE10.000000WZSGEcanceledWheatley
023000632510ACIS-SNONE10.000000WZSGEcanceledWheatley
023000622509ACIS-SNONE10.000000WZSGEcanceledWheatley
023000552466ACIS-SNONE2.000000CIAQLcanceledGreiner
025002022461ACIS-SNONE5.000000SGR1900+14canceledKouveliotou
025002012460ACIS-SNONE5.000000SGR1900+14canceledKouveliotou
025001982457ACIS-SNONE20.000000SGR1900+14canceledKulkarni
014001131847ACIS-SNONE5.000000XTEJ1550-564canceledTomsick

Sequence Number: 503371

Title : A precise position for the likely very local GRB 220611A
PI: Levan
Abstract: GRB 220611A is a long duration GRB located 15 from an S0 galaxy at a
distance of only 220 Mpc (the third closest GRB in 18 years of Swift
operations). It has a very low probability of chance alignment (0.3%).
However, the host galaxy shows no sign of star formation, and the
offset is more in keeping with short GRBs formed from compact object
mergers than from long bursts formed from collapsars. Recent evidence
suggests that long bursts can be formed from mergers, and so this is a
plausible channel for GRB 220611A. The RA of the burst is such that it
cannot be viewed from the ground, and so we currently lack an accurate
position. However, Chandra observations can pinpoint the afterglow
within its host, revealing any star formation at the burst location,
or a more distant galaxy should the burst arise from a chance
alignment. Such a precise position can therefore greatly enhance (or
repudiate) the possibility that the burst is at 220 Mpc and inform the
collapsar/merger origin.

Sequence Number: 402361

Title : Disk winds in IGR J17091-3624 in the exotic variability state
PI: Wang
Abstract: IGRJ17091-3624 is a peculiar black hole binary (BHB) as it exhibits
exotic variability patterns that are highly structured, very similar
to GRS 1915+105. After the two major outbursts in 2011 and 2016,
IGRJ17091-3624 went into a new outburst in March 2022. With our NICER
and NuSTAR campaign, we observe Fe XXV and Fe XXVI absorption lines in
NICER spectra in the exotic variability state. These absorption lines
indicate the presence of disk winds, which are crucial to understand
the nature of the exotic variability of accretion flow thought to be
due to disk instability either because the black hole accretes at a
high mass accretion rate close to the Eddington limit, or disk
tearing. We request 1 Chandra/HETG observation of 30 ks to study the
disk winds in IGRJ17091-3624 in its current exotic variability state.
Joint observations with our approved NICER and NuSTAR GO program
(#5118) are highly favored.

Sequence Number: 402360

Title : Chandra high-resolution imaging of a new transient ultraluminous X-ray
source in M81
PI: Brightman
Abstract: We propose a Chandra DDT observation of a newly discovered X-ray
source in the nearby (3.7 Mpc) spiral galaxy M81. The source seems to
be a new ultraluminous X-ray source (ULX) that has recently appeared,
never before detected, despite numerous X-ray observations of the
galaxy. This source is one of a handful of transient ULXs we have
discovered recently while searching through Swift/XRT observations.
These new ULXs appear to lie among an older stellar population, where
models imply neutron star accretors are dominant. Unlike the previous
sources identified, M81 has ample HST coverage allowing a search for
an optical counterpart, and to age the stellar population of its
environment. There are also candidate optical transients from ZTF in
the Swift localization region. A 10-ks Chandra observation will
provide the accurate X-ray position to identify the counterpart.

Sequence Number: 402359

Title : Confirmation of a candidate nearby off-axis short GRB
PI: Gompertz
Abstract: GRB 220412B is an extremely short duration gamma-ray burst lasting
just 140ms. Prompt X-ray and optical follow-up revealed no
corresponding afteglow to deep limits at early times. However, our VLA
observations at 10 days after trigger reveal a bright (~380 uJy)
uncataloged radio source offset just a few arcseconds from the center
of the BAT localisation. These observations are consistent with an
off-axis' GRB wherein the jet is not directly pointed towards Earth.
The afterglow is initially beamed away from the observer and is later
seen to rise as the relativistic Doppler beaming lessens. The radio
source is not coincident with any known galaxy nor optical emission in
archival images. We therefore request observations with Chandra to
explore its multi-wavelength properties and potentially confirm it as
the GRB afterglow in the local Universe.

Sequence Number: 201530

Title : A Chandra and ALMA View of the Origin and Impact of M-dwarf Flares
PI: Howard
Abstract: Recently, a large millimeter flare was detected from Proxima Cen.
Since little is known about millimeter flares, we have been awarded 40
hours of upcoming ALMA Cycle 8 observations to determine UV-millimeter
flare relationships using nearby M-dwarfs of various ages and activity
levels. We propose simultaneous ACIS HETG observations of the most
active target (Wolf 359) to constrain the high-energy spectral
properties of millimeter flares and their potential impact on planets.
We apply for DDT time as the ALMA scheduling will occur soon. Previous
observations of Proxima Cen by Chandra and ALMA show X-ray and
millimeter flares trace each other closely, and this proposed study
will help determine if this is a universal property of mid-M dwarfs
regardless of age, thereby creating a powerful new tool to determine
the high-energy environment of stars.

Sequence Number: 201529

Title : A Chandra and ALMA View of the Origin and Impact of M-dwarf Flares
PI: Howard
Abstract: Recently, a large millimeter flare was detected from Proxima Cen.
Since little is known about millimeter flares, we have been awarded 40
hours of upcoming ALMA Cycle 8 observations to determine UV-millimeter
flare relationships using nearby M-dwarfs of various ages and activity
levels. We propose simultaneous ACIS HETG observations of the most
active target (Wolf 359) to constrain the high-energy spectral
properties of millimeter flares and their potential impact on planets.
We apply for DDT time as the ALMA scheduling will occur soon. Previous
observations of Proxima Cen by Chandra and ALMA show X-ray and
millimeter flares trace each other closely, and this proposed study
will help determine if this is a universal property of mid-M dwarfs
regardless of age, thereby creating a powerful new tool to determine
the high-energy environment of stars.

Sequence Number: 201528

Title : A Chandra and ALMA View of the Origin and Impact of M-dwarf Flares
PI: Howard
Abstract: Recently, a large millimeter flare was detected from Proxima Cen.
Since little is known about millimeter flares, we have been awarded 40
hours of upcoming ALMA Cycle 8 observations to determine UV-millimeter
flare relationships using nearby M-dwarfs of various ages and activity
levels. We propose simultaneous ACIS HETG observations of the most
active target (Wolf 359) to constrain the high-energy spectral
properties of millimeter flares and their potential impact on planets.
We apply for DDT time as the ALMA scheduling will occur soon. Previous
observations of Proxima Cen by Chandra and ALMA show X-ray and
millimeter flares trace each other closely, and this proposed study
will help determine if this is a universal property of mid-M dwarfs
regardless of age, thereby creating a powerful new tool to determine
the high-energy environment of stars.

Sequence Number: 704610

Title : A Delayed Jet in a Tidal Disruption Event
PI: Cendes
Abstract: We request a 15 ksec DDT observation of the tidal disruption event
(TDE) AT2018hyz, which has begun rapidly brightening in the radio/mm
~2.2 years post-disruption despite no prior radio detections. Our
radio/mm data are potentially indicative of a relativistic jet
launched with an unexpectedly long delay relative to the time of
disruption, making this the first TDE with evidence for a delayed jet
(and only the second relativistic jet overall). Because the
synchrotron cooling frequency lies above the radio/mm band, Chandra
observations are crucial to pinpoint its location in order to
determine if the outflow is in equipartition, and to accurately
determine its radius, velocity, and energy, as well as the ambient
density around the supermassive black hole. If the Chandra
observations confirm a delayed relativistic outflow, this would
indicate that TDE jets can be produced at low accretion rates rather
than in the early super-Eddington phase.

Sequence Number: 704603

Title : Probing the X-rays from an unprecedented SMBH Binary at the Last
Inspiraling Stage
PI: Jiang
Abstract: We have recently discovered the first likely SMBH merger event ever
discovered in human history. The final merger will happen within three
years, maybe as short as three months. High-quality X-ray spectra
might be one of the most powerful electromagnetic signal to study the
last inspiraling stage. Our requested XMM-Newton ToO observations on
Dec.31 and Jan.19 have unveiled ultra-high velocity (>0.1c) absorbers
with drastic change, that is natural in binary scenario but never been
seen in normal AGNs. Chandra turns out to be the only facility which
can further monitor the unprecedented target with high-quality spectra
in the next five months (from Feb. To June, visibility gap for
XMM-Newton). Hopefully Chandra will contribute significantly to
confirm the first SMBH binary merger event and explore high energy
physical process happening during the final stage of the binary
inspiral.

Sequence Number: 704603

Title : Probing the X-rays from an unprecedented SMBH Binary at the Last
Inspiraling Stage
PI: Jiang
Abstract: We have recently discovered the first likely SMBH merger event ever
discovered in human history. The final merger will happen within three
years, maybe as short as three months. High-quality X-ray spectra
might be one of the most powerful electromagnetic signal to study the
last inspiraling stage. Our requested XMM-Newton ToO observations on
Dec.31 and Jan.19 have unveiled ultra-high velocity (>0.1c) absorbers
with drastic change, that is natural in binary scenario but never been
seen in normal AGNs. Chandra turns out to be the only facility which
can further monitor the unprecedented target with high-quality spectra
in the next five months (from Feb. To June, visibility gap for
XMM-Newton). Hopefully Chandra will contribute significantly to
confirm the first SMBH binary merger event and explore high energy
physical process happening during the final stage of the binary
inspiral.

Sequence Number: 704603

Title : Probing the X-rays from an unprecedented SMBH Binary at the Last
Inspiraling Stage
PI: Jiang
Abstract: We have recently discovered the first likely SMBH merger event ever
discovered in human history. The final merger will happen within three
years, maybe as short as three months. High-quality X-ray spectra
might be one of the most powerful electromagnetic signal to study the
last inspiraling stage. Our requested XMM-Newton ToO observations on
Dec.31 and Jan.19 have unveiled ultra-high velocity (>0.1c) absorbers
with drastic change, that is natural in binary scenario but never been
seen in normal AGNs. Chandra turns out to be the only facility which
can further monitor the unprecedented target with high-quality spectra
in the next five months (from Feb. To June, visibility gap for
XMM-Newton). Hopefully Chandra will contribute significantly to
confirm the first SMBH binary merger event and explore high energy
physical process happening during the final stage of the binary
inspiral.

Sequence Number: 704603

Title : Probing the X-rays from an unprecedented SMBH Binary at the Last
Inspiraling Stage
PI: Jiang
Abstract: We have recently discovered the first likely SMBH merger event ever
discovered in human history. The final merger will happen within three
years, maybe as short as three months. High-quality X-ray spectra
might be one of the most powerful electromagnetic signal to study the
last inspiraling stage. Our requested XMM-Newton ToO observations on
Dec.31 and Jan.19 have unveiled ultra-high velocity (>0.1c) absorbers
with drastic change, that is natural in binary scenario but never been
seen in normal AGNs. Chandra turns out to be the only facility which
can further monitor the unprecedented target with high-quality spectra
in the next five months (from Feb. To June, visibility gap for
XMM-Newton). Hopefully Chandra will contribute significantly to
confirm the first SMBH binary merger event and explore high energy
physical process happening during the final stage of the binary
inspiral.

Sequence Number: 704603

Title : Probing the X-rays from an unprecedented SMBH Binary at the Last
Inspiraling Stage
PI: Jiang
Abstract: We have recently discovered the first likely SMBH merger event ever
discovered in human history. The final merger will happen within three
years, maybe as short as three months. High-quality X-ray spectra
might be one of the most powerful electromagnetic signal to study the
last inspiraling stage. Our requested XMM-Newton ToO observations on
Dec.31 and Jan.19 have unveiled ultra-high velocity (>0.1c) absorbers
with drastic change, that is natural in binary scenario but never been
seen in normal AGNs. Chandra turns out to be the only facility which
can further monitor the unprecedented target with high-quality spectra
in the next five months (from Feb. To June, visibility gap for
XMM-Newton). Hopefully Chandra will contribute significantly to
confirm the first SMBH binary merger event and explore high energy
physical process happening during the final stage of the binary
inspiral.

Sequence Number: 704603

Title : Probing the X-rays from an unprecedented SMBH Binary at the Last
Inspiraling Stage
PI: Jiang
Abstract: We have recently discovered the first likely SMBH merger event ever
discovered in human history. The final merger will happen within three
years, maybe as short as three months. High-quality X-ray spectra
might be one of the most powerful electromagnetic signal to study the
last inspiraling stage. Our requested XMM-Newton ToO observations on
Dec.31 and Jan.19 have unveiled ultra-high velocity (>0.1c) absorbers
with drastic change, that is natural in binary scenario but never been
seen in normal AGNs. Chandra turns out to be the only facility which
can further monitor the unprecedented target with high-quality spectra
in the next five months (from Feb. To June, visibility gap for
XMM-Newton). Hopefully Chandra will contribute significantly to
confirm the first SMBH binary merger event and explore high energy
physical process happening during the final stage of the binary
inspiral.

Sequence Number: 704603

Title : Probing the X-rays from an unprecedented SMBH Binary at the Last
Inspiraling Stage
PI: Jiang
Abstract: We have recently discovered the first likely SMBH merger event ever
discovered in human history. The final merger will happen within three
years, maybe as short as three months. High-quality X-ray spectra
might be one of the most powerful electromagnetic signal to study the
last inspiraling stage. Our requested XMM-Newton ToO observations on
Dec.31 and Jan.19 have unveiled ultra-high velocity (>0.1c) absorbers
with drastic change, that is natural in binary scenario but never been
seen in normal AGNs. Chandra turns out to be the only facility which
can further monitor the unprecedented target with high-quality spectra
in the next five months (from Feb. To June, visibility gap for
XMM-Newton). Hopefully Chandra will contribute significantly to
confirm the first SMBH binary merger event and explore high energy
physical process happening during the final stage of the binary
inspiral.

Sequence Number: 704603

Title : Probing the X-rays from an unprecedented SMBH Binary at the Last
Inspiraling Stage
PI: Jiang
Abstract: We have recently discovered the first likely SMBH merger event ever
discovered in human history. The final merger will happen within three
years, maybe as short as three months. High-quality X-ray spectra
might be one of the most powerful electromagnetic signal to study the
last inspiraling stage. Our requested XMM-Newton ToO observations on
Dec.31 and Jan.19 have unveiled ultra-high velocity (>0.1c) absorbers
with drastic change, that is natural in binary scenario but never been
seen in normal AGNs. Chandra turns out to be the only facility which
can further monitor the unprecedented target with high-quality spectra
in the next five months (from Feb. To June, visibility gap for
XMM-Newton). Hopefully Chandra will contribute significantly to
confirm the first SMBH binary merger event and explore high energy
physical process happening during the final stage of the binary
inspiral.

Sequence Number: 704603

Title : Probing the X-rays from an unprecedented SMBH Binary at the Last
Inspiraling Stage
PI: Jiang
Abstract: We have recently discovered the first likely SMBH merger event ever
discovered in human history. The final merger will happen within three
years, maybe as short as three months. High-quality X-ray spectra
might be one of the most powerful electromagnetic signal to study the
last inspiraling stage. Our requested XMM-Newton ToO observations on
Dec.31 and Jan.19 have unveiled ultra-high velocity (>0.1c) absorbers
with drastic change, that is natural in binary scenario but never been
seen in normal AGNs. Chandra turns out to be the only facility which
can further monitor the unprecedented target with high-quality spectra
in the next five months (from Feb. To June, visibility gap for
XMM-Newton). Hopefully Chandra will contribute significantly to
confirm the first SMBH binary merger event and explore high energy
physical process happening during the final stage of the binary
inspiral.

Sequence Number: 704603

Title : Probing the X-rays from an unprecedented SMBH Binary at the Last
Inspiraling Stage
PI: Jiang
Abstract: We have recently discovered the first likely SMBH merger event ever
discovered in human history. The final merger will happen within three
years, maybe as short as three months. High-quality X-ray spectra
might be one of the most powerful electromagnetic signal to study the
last inspiraling stage. Our requested XMM-Newton ToO observations on
Dec.31 and Jan.19 have unveiled ultra-high velocity (>0.1c) absorbers
with drastic change, that is natural in binary scenario but never been
seen in normal AGNs. Chandra turns out to be the only facility which
can further monitor the unprecedented target with high-quality spectra
in the next five months (from Feb. To June, visibility gap for
XMM-Newton). Hopefully Chandra will contribute significantly to
confirm the first SMBH binary merger event and explore high energy
physical process happening during the final stage of the binary
inspiral.

Sequence Number: 704603

Title : Probing the X-rays from an unprecedented SMBH Binary at the Last
Inspiraling Stage
PI: Jiang
Abstract: We have recently discovered the first likely SMBH merger event ever
discovered in human history. The final merger will happen within three
years, maybe as short as three months. High-quality X-ray spectra
might be one of the most powerful electromagnetic signal to study the
last inspiraling stage. Our requested XMM-Newton ToO observations on
Dec.31 and Jan.19 have unveiled ultra-high velocity (>0.1c) absorbers
with drastic change, that is natural in binary scenario but never been
seen in normal AGNs. Chandra turns out to be the only facility which
can further monitor the unprecedented target with high-quality spectra
in the next five months (from Feb. To June, visibility gap for
XMM-Newton). Hopefully Chandra will contribute significantly to
confirm the first SMBH binary merger event and explore high energy
physical process happening during the final stage of the binary
inspiral.

Sequence Number: 704603

Title : Probing the X-rays from an unprecedented SMBH Binary at the Last
Inspiraling Stage
PI: Jiang
Abstract: We have recently discovered the first likely SMBH merger event ever
discovered in human history. The final merger will happen within three
years, maybe as short as three months. High-quality X-ray spectra
might be one of the most powerful electromagnetic signal to study the
last inspiraling stage. Our requested XMM-Newton ToO observations on
Dec.31 and Jan.19 have unveiled ultra-high velocity (>0.1c) absorbers
with drastic change, that is natural in binary scenario but never been
seen in normal AGNs. Chandra turns out to be the only facility which
can further monitor the unprecedented target with high-quality spectra
in the next five months (from Feb. To June, visibility gap for
XMM-Newton). Hopefully Chandra will contribute significantly to
confirm the first SMBH binary merger event and explore high energy
physical process happening during the final stage of the binary
inspiral.

Sequence Number: 704603

Title : Probing the X-rays from an unprecedented SMBH Binary at the Last
Inspiraling Stage
PI: Jiang
Abstract: We have recently discovered the first likely SMBH merger event ever
discovered in human history. The final merger will happen within three
years, maybe as short as three months. High-quality X-ray spectra
might be one of the most powerful electromagnetic signal to study the
last inspiraling stage. Our requested XMM-Newton ToO observations on
Dec.31 and Jan.19 have unveiled ultra-high velocity (>0.1c) absorbers
with drastic change, that is natural in binary scenario but never been
seen in normal AGNs. Chandra turns out to be the only facility which
can further monitor the unprecedented target with high-quality spectra
in the next five months (from Feb. To June, visibility gap for
XMM-Newton). Hopefully Chandra will contribute significantly to
confirm the first SMBH binary merger event and explore high energy
physical process happening during the final stage of the binary
inspiral.

Sequence Number: 704603

Title : Probing the X-rays from an unprecedented SMBH Binary at the Last
Inspiraling Stage
PI: Jiang
Abstract: We have recently discovered the first likely SMBH merger event ever
discovered in human history. The final merger will happen within three
years, maybe as short as three months. High-quality X-ray spectra
might be one of the most powerful electromagnetic signal to study the
last inspiraling stage. Our requested XMM-Newton ToO observations on
Dec.31 and Jan.19 have unveiled ultra-high velocity (>0.1c) absorbers
with drastic change, that is natural in binary scenario but never been
seen in normal AGNs. Chandra turns out to be the only facility which
can further monitor the unprecedented target with high-quality spectra
in the next five months (from Feb. To June, visibility gap for
XMM-Newton). Hopefully Chandra will contribute significantly to
confirm the first SMBH binary merger event and explore high energy
physical process happening during the final stage of the binary
inspiral.

Sequence Number: 704603

Title : Probing the X-rays from an unprecedented SMBH Binary at the Last
Inspiraling Stage
PI: Jiang
Abstract: We have recently discovered the first likely SMBH merger event ever
discovered in human history. The final merger will happen within three
years, maybe as short as three months. High-quality X-ray spectra
might be one of the most powerful electromagnetic signal to study the
last inspiraling stage. Our requested XMM-Newton ToO observations on
Dec.31 and Jan.19 have unveiled ultra-high velocity (>0.1c) absorbers
with drastic change, that is natural in binary scenario but never been
seen in normal AGNs. Chandra turns out to be the only facility which
can further monitor the unprecedented target with high-quality spectra
in the next five months (from Feb. To June, visibility gap for
XMM-Newton). Hopefully Chandra will contribute significantly to
confirm the first SMBH binary merger event and explore high energy
physical process happening during the final stage of the binary
inspiral.

Sequence Number: 402355

Title : An Intermediate Mass Black Hole Candidate at the Centre of 47 Tuc
PI: Paduano
Abstract: We are currently in the middle of a large radio observing campaign
(406 hr) with the Australia Telescope Compact Array (ATCA) which will
produce the deepest radio image of the globular cluster 47 Tucanae to
identify faintly accreting black holes. Preliminary results from our
ongoing campaign based on data acquired in April/July/October 2021
have identified a radio counterpart to a previously identified faint
X-ray source. Its location at the photometric centre of the cluster
implies this object could be an intermediate mass black hole (IMBH)
candidate. As 47 Tucanae has not been observed by Chandra since 2015,
we request a 20 ks observation quasi-simultaneous with the last
segment of our ATCA observations to rule out the possibility of
enhanced radio/X-ray activity from an XRB. This will allow us to
assess the presence of an accreting IMBH in a globular cluster based
on direct evidence for the first time.

Sequence Number: 503370

Title : Search for the X-ray counterpart to GLEAM-X J162759.5-523504.3
PI: Hurley-Walker
Abstract: During a Galactic Plane survey with the Murchison Widefield Array
(MWA), a peculiar periodic radio transient has been discovered
(Hurley-Walker et al. 2021, Nature in press; info under embargo) with
a periodicity of 1091.169(5) s, a very variable flux, going from
undetected to values as high as 20-50Jy during periods of radio
outburst, lasting a few months (two such periods were observed in
January and March 2018), with a 90% linear polarization, and a very
spiky and variable pulse profile. From a detailed timing analysis, a
dispersion measure of DM=57+/-1 pc cm^-3 was calculated (distance~1.3
kpc). We expect this to be a magnetar having witnessed a conspicuous
fall-back accretion at birth that slew down its spin period
substantially. A short Swift XRT observation of ~5ks could constrain
its X-ray luminosity to < 10^33 erg/s. If it is a magnetar the source
might have in quiescence, a luminosity of ~10^30 erg/s. Deeper X-ray
observations are needed to set meaningful constraints.

Sequence Number: 402357

Title : Tracking the X-ray Emission of the Remarkable SGRB 211106A
PI: Rouco Escorial
Abstract: The distribution of jet angles for short gamma-ray bursts (SGRBs) is
critical to constrain as it directly affects the true energy scale and
event rate, which is of particular interest in the midst of the new
LVK run for next year. Our current knowledge of the jet angle
distribution comes almost exclusively from X-ray observations at >1
day after the burst. Here, we propose for a Chandra DDT observation to
continue to monitor the afterglow of SGRB 211106A and constrain its
late-time collimation up to ~60 days post-trigger, either from the
detection of the X-ray afterglow, which places a lower limit on the
opening angle at >15 deg, or a non-detection of the afterglow,
indicating a jet break has occurred and constraining the jet break to
20-25 deg. We have broad-band afterglow observations, which will be
leveraged to provide the tightest constraints on the jet angle.

Sequence Number: 402357

Title : Tracking the X-ray Emission of the Remarkable SGRB 211106A
PI: Rouco Escorial
Abstract: The distribution of jet angles for short gamma-ray bursts (SGRBs) is
critical to constrain as it directly affects the true energy scale and
event rate, which is of particular interest in the midst of the new
LVK run for next year. Our current knowledge of the jet angle
distribution comes almost exclusively from X-ray observations at >1
day after the burst. Here, we propose for a Chandra DDT observation to
continue to monitor the afterglow of SGRB 211106A and constrain its
late-time collimation up to ~60 days post-trigger, either from the
detection of the X-ray afterglow, which places a lower limit on the
opening angle at >15 deg, or a non-detection of the afterglow,
indicating a jet break has occurred and constraining the jet break to
20-25 deg. We have broad-band afterglow observations, which will be
leveraged to provide the tightest constraints on the jet angle.

Sequence Number: 402356

Title : The wide angle outflow of SGRB 210726A
PI: Schroeder
Abstract: The distribution of jet angles for short gamma-ray bursts (SGRBs) is
critical to constrain as it directly affects the true energy scale and
event rate. The event rate is of particular interest in the
gravitational wave era. Our current knowledge of the jet angle
distribution comes almost exclusively from X-ray observations at >1
day after the burst. Here, we propose for a Chandra TOO observation to
continue to monitor the afterglow of SGRB 210726A and constrain its
collimation, either from the detection of the X-ray afterglow, which
places a lower limit on the opening angle at >35 deg, or a
non-detection of the afterglow, indicating a jet break has occurred
and constraining the jet break to 13-35 deg. We have broad-band
afterglow observations, which will be leveraged to provide the
tightest constraints on the jet angle. This would be the first
detection of a cosmological SGRB afterglow at >50 days, complementing
the longest lasting detections of an SGRB radio afterglow.

Sequence Number: 402355

Title : An Intermediate Mass Black Hole Candidate at the Centre of 47 Tuc
PI: Paduano
Abstract: We are currently in the middle of a large radio observing campaign
(406 hr) with the Australia Telescope Compact Array (ATCA) which will
produce the deepest radio image of the globular cluster 47 Tucanae to
identify faintly accreting black holes. Preliminary results from our
ongoing campaign based on data acquired in April/July/October 2021
have identified a radio counterpart to a previously identified faint
X-ray source. Its location at the photometric centre of the cluster
implies this object could be an intermediate mass black hole (IMBH)
candidate. As 47 Tucanae has not been observed by Chandra since 2015,
we request a 20 ks observation quasi-simultaneous with the last
segment of our ATCA observations to rule out the possibility of
enhanced radio/X-ray activity from an XRB. This will allow us to
assess the presence of an accreting IMBH in a globular cluster based
on direct evidence for the first time.

Sequence Number: 503370

Title : Search for the X-ray counterpart to GLEAM-X J162759.5-523504.3
PI: Hurley-Walker
Abstract: During a Galactic Plane survey with the Murchison Widefield Array
(MWA), a peculiar periodic radio transient has been discovered
(Hurley-Walker et al. 2021, Nature in press; info under embargo) with
a periodicity of 1091.169(5) s, a very variable flux, going from
undetected to values as high as 20-50Jy during periods of radio
outburst, lasting a few months (two such periods were observed in
January and March 2018), with a 90% linear polarization, and a very
spiky and variable pulse profile. From a detailed timing analysis, a
dispersion measure of DM=57+/-1 pc cm^-3 was calculated (distance~1.3
kpc). We expect this to be a magnetar having witnessed a conspicuous
fall-back accretion at birth that slew down its spin period
substantially. A short Swift XRT observation of ~5ks could constrain
its X-ray luminosity to < 10^33 erg/s. If it is a magnetar the source
might have in quiescence, a luminosity of ~10^30 erg/s. Deeper X-ray
observations are needed to set meaningful constraints.

Sequence Number: 503369

Title : Ejecta Collimation and True Energetics of GRB210905A at z=6.318
PI: MARGUTTI
Abstract: We propose deep Chandra observations of GRB210905A at z=6.318 to
solidly locate the afterglow jet break time, and hence constrain the
ejecta collimation and true energetic of a GRB belonging to the rare
class of z>6 burst

Sequence Number: 704586

Title : Was the TDE candidate eRASSt J0936 produced by a wandering SMBH?
PI: Malyali
Abstract: On 2021-05-13, eROSITA detected a new TDE candidate, characterised by
an ultra-soft (kT~70 eV) X-ray spectrum and associated with a recently
quiescent FRII galaxy at z=0.12 (eRASSt J0936; see ATel#14668).
Follow-up Swift observations since the eROSITA detection revealed a
declining X-ray flux, with no significant X-ray spectral change (i.e.
remains ultra-soft); the latest observed 0.2-2 keV flux was
(5+/-3)e-14 erg/s/cm2 on 2021-10-06.
The implied SMBH mass from the M-sigma relation for this galaxy is
log(Mbh/Msun)~8.8, which exceeds the Hills mass for tidal disruption
of a MS star by a non-spinning SMBH. Recent work suggests a
significant fraction of TDEs may be produced by wandering SMBHs that
lie off-nuclear in their host (Fig. 2 of Ricarte+ in arXiv
2107.02132)- this may explain why we see a TDE candidate in a galaxy
with log(Mbh/Msun)~8.8. We request a 30ks observation of J0936 with
HRC-I to constrain the location of J0936 to within ~1.1 kpc (0.5; 3
sig.) of the host's centre.

Sequence Number: 402354

Title : Determining the Mass of the IC 10 X-1 Black Hole with Coordinated
Multiwavelength Observations
PI: Binder
Abstract: We request a 30 ks DDT Chandra/ACIS-S observation of the black hole
(BH) + Wolf-Rayet (WR) binary IC 10 X-1 to complement approved
Hubble/COS FUV spectroscopy and Swift/XRT+UVOT monitoring between 9-22
Nov 2021. The Chandra observation will allow us to determine the
orbital phases at which the Hubble and Swift observations are obtained
to high precision, model the X-ray spectrum and radiation field in
which the FUV lines form, and constrain the period derivative Pdot of
the system.

Sequence Number: 503368

Title : VLA+Chandra Observations of Ic-BL Supernovae with ZTF High-Cadence
Light Curves
PI: Ho
Abstract: Broad-lined Ic supernovae (Ic-BL) are a subclass of stripped-envelope
core-collapse supernovae notable for their high energies, high
velocities, and association with long-duration gamma-ray bursts
(GRBs). After decades of follow-up efforts, it remains unknown why
most Ic-BL SNe lack a detected GRB. Nearby (z<0.065) Ic-BL SNe
associated with low-luminosity GRBs (LLGRBs) may represent the answer:
LLGRB-SNe have been argued to be jets viewed off-axis, jets choked
inside the stellar envelope or circumstellar material, or successful
jets that are less powerful than classical GRBs. Here we propose
observations of ZTF21acekmmm to test a novel approach, based on the
fact that nearby LLGRB-SNe exhibit an early (<1d) flash of optical
light that can be routinely resolved by high-cadence optical surveys
like the Zwicky Transient Facility.

Sequence Number: 402353

Title : HIGH RESOLUTION STUDIES OF EXO 2030+375 DURING THE PEAK AND DECLINE OF
ITS RARE GIANT OUTBURST
PI: Pradhan
Abstract: As of Sep 10, EXO 2030+375 is rising in BAT indicative of the onset of
giant erratic Type II outburst seen only twice in the source since
discovery. We take this rare opportunity to study high-res
characteristics of the source near outburst peak and during its
decline for 10 ks and 20 ks respectively. We will probe accretion
near Eddington luminosity and disk winds through the study of the
X-ray continuum, emission lines and high velocity outflows. Since the
luminosity at giant outbursts are also thought to be accompanied by
such high velocity out seen in a few Be X-ray binaries so far, we
expect to find the outflows in EXO 2030+375. We will also: look for
variability of fluorescence lines originating in accretion disk and
place constraints on the Alfven radius to provide a magnetic field
estimate of the neutron star in the system and investigate the
scattering halos by studying the differences between the source and
halo light curves.

Sequence Number: 503296

Title : A luminous kilonova or a faint supernova? The curious case of
GRB210704A
PI: Troja
Abstract: GRB210704A is a GRB of intermediate duration (T90~4 s) whose
progenitor remains uncertain. Its location in a nearby galaxy's
cluster as well as the lack of any on-going star formation support an
old progenitor system, such as a compact binary merger. However, its
duration and bright long-lived afterglow are more typical of a long
duration burst. Its hybrid properties may also point to an exotic
channel of formation, such as as the merger of a white dwarf/black
hole system. We request a Chandra observation to track the evolution
of its non-thermal emission to late times, when the source has faded
below the Swift XRT detection threshold. These observations are
critical to characterize the standard afterglow, identify any excess
emission, and ultimately understand the nature of the shallow
optical/nIR decay which is a direct clue to the GRB progenitor
system.

Sequence Number: 300502

Title : Dissecting the Supersoft Source Phase of the Magnetic Nova V1674 Her
(Nova Her 2021)
PI: Drake
Abstract: V1674 Her (Nova Her 2021) is the first bright nova supersoft source
that has been identified with a magnetic white dwarf progenitor. An
8.357 minute period was found in ZTF data taken between 2018 and 2021
that is most likely caused by the spin period of the WD, strongly
indicating an intermediate polar. The presence of strong neon emission
lines in spectra from 2021 June 30 also demonstrate that V1674 Her is
a member of the class of neon novae. It has become a very bright
supersoft X-ray source with a Swift XRT count rate of 10 count/s. A
Chandra LETG+HRC-S spectrum should be uncomplicated by accretion and
can be phase-folded with the known period. It will provide a powerful
test of whether or not nuclear burning is insensitive to the local
magnetic field, and reveal velocity signatures of radiatively-driven
outflow collimation. V1674 Her is the first bright SSS to be so
characterized prior to outburst.

Sequence Number: 300501

Title : Searching for pulsations in a magnetic CV's nova
PI: Maccarone
Abstract: The bright, fast nova TCP J18573095+1653396 has shown an 8.4 minute
period in ZTF data that were taken before the nova explosion. This
period makes sense as a magnetized white dwarf's spin period. This
creates the potential for determining if the supersoft phases of these
systems show the spin oscillations of the white dwarfs. The period is
an awkward one for being reliably detected by satellites with
low-Earth orbits, so a short Chandra observation is requested.

Sequence Number: 402298

Title : HETG Spectroscopy of the Black Hole 4U 1543-475
PI: Miller
Abstract: 4U 1543-475 is a recurrent black hole X-ray binary. It is one of the
few sources with a dynamically confirmed mass, and measured distance
(M = 9.4 +/- 2.0 Msun, distance = 7.5 +/- 1.0 kpc; Park et al. 2004).
This means that it is a rare case wherein black hole spin can be
measured using continuum fitting. The source has risen very quickly
from the detection of renewed activity only (up to 2.5-3 Crab in just
2-3 days, see ATEL 14701). It is now in the soft state, which is the
one wherein spin can be measured as other contributions to the
continuum are minimal. In this state, disk winds and UFOs can also be
detected using the HETGS. With the ACIS-S array in CC mode, Chandra
is uniquely able to observe a source this bright without distortions.

Sequence Number: 503295

Title : Chandra Observation of AT2020mrf: the Most X-ray Luminous AT2018cow
Analog
PI: Yao
Abstract: The past several years has shown that the landscape of massive-star
death is unexpectedly rich and diverse. The (heterogeneous) class of
fast blue optical transients'' (FBOT) has now established that a
large fraction of massive stars undergo significant mass losses, and
in some cases these losses serve as omens of their deaths
(supernovae). The discovery of AT2018cow (z=0.0141) established a
genuinely new type of cosmic explosion. AT2018cow was not only an FBOT
but was marked by intense X-ray emission and variability which
requires a powerful long-lived engine. Its high radio luminosity and
late millimeter peak implied dense circum-stellar medium (CSM).
Following the discovery of AT2018cow two events, ZTF18abvkwla
(z=0.271), CSS161010 (z=0.034; archival analysis), and AT2020xnd
(z=0.244) were identified. A fundamental open question is the nature
of the central engine. The X-ray band is essential since it probes
materials closest to the central power source.

Sequence Number: 402296

Title : Probing the disc-wind-jet connection in black hole transients
PI: Diaz Trigo
Abstract: We request three 50 ks observations of the candidate black hole
low-mass X-ray binary MAXI J1803-298 during the hard-to-soft state
transition with Chandra/HETGS to investigate the presence of narrow
X-ray absorption/emission features in the spectra, which are a
signature of a disc wind, and their relation to the accreting regime.
Such features, identified with ions like Fe XXV and Fe XXVI give us
information about the mass outflow rate and the launching mechanism of
the wind. With coordinated radio observations we will probe the
relationship between jet power and wind properties and how the radio
flux density correlates with the X-ray flux in different accretion
regimes.

Sequence Number: 704293

Title : Chandra grating observations of a newly launched outflow from a
supermassive black hole during an outburst
PI: Pasham
Abstract: We are requesting for a 50ks Chandra/LETG exposure of the nuclear
transient AT2019avd following NICER discovery of an outflow. LETG data
would provide a detailed view of this newly launched outflow as the
supermassive black hole (SMBH) is currently transitioning from an
X-ray soft to an X-ray hard state. This is analogous to a high/soft to
low/hard state transition in X-ray binaries which is often accompanied
by outflows. NICER has been monitoring AT2019avd at an unprecedented
cadence of once to several visits per day since its first public X-ray
detection on 19 Sept 2020. The proposed Chandra data will be part of
the legacy dataset to study accretion state transitions in SMBHs and
will guide future observations of SMBH outbursts with the upcoming
XRISM mission. This state transition and outflow could not have been
predicted at the time Chandra GO proposals were due and this
opportunity will not be available until the next GO cycle as the
source is already declining in flux.

Sequence Number: 704293

Title : Chandra grating observations of a newly launched outflow from a
supermassive black hole during an outburst
PI: Pasham
Abstract: We are requesting for a 50ks Chandra/LETG exposure of the nuclear
transient AT2019avd following NICER discovery of an outflow. LETG data
would provide a detailed view of this newly launched outflow as the
supermassive black hole (SMBH) is currently transitioning from an
X-ray soft to an X-ray hard state. This is analogous to a high/soft to
low/hard state transition in X-ray binaries which is often accompanied
by outflows. NICER has been monitoring AT2019avd at an unprecedented
cadence of once to several visits per day since its first public X-ray
detection on 19 Sept 2020. The proposed Chandra data will be part of
the legacy dataset to study accretion state transitions in SMBHs and
will guide future observations of SMBH outbursts with the upcoming
XRISM mission. This state transition and outflow could not have been
predicted at the time Chandra GO proposals were due and this
opportunity will not be available until the next GO cycle as the
source is already declining in flux.

Sequence Number: 402297

Title : The disk/jet connection of a black hole in quiescence
PI: Carotenuto
Abstract: Black hole X-ray binaries display a correlation between the radio
luminosity originating from the relativistic jets, and the X-ray
luminosity, linked to the inner accretion flow. Some outlier (hybrid)
sources display a correlation that varies with the accretion rate, and
their behaviour in quiescence is still unknown. The path of a source
on the radio/X-ray diagram can be used to test models of accretion
flows and jets emission mechanisms. The new BH MAXI J1348-630 has been
densely monitored during its 2019/2020 outburst and is, so far, the
hybrid source with the best coverage, but its quiescence level has not
been constrained yet. We propose a single DDT Chandra observation (30
ks), that will be coupled to a deep radio observation (24h with ATCA)
in July 2021 (already scheduled), which will allow us to detect an
hybrid source in quiescence and therefore constrain its full path
along the radio/X-ray diagram from outburst down to quiescence.

Sequence Number: 503295

Title : Chandra Observation of AT2020mrf: the Most X-ray Luminous AT2018cow
Analog
PI: Yao
Abstract: The past several years has shown that the landscape of massive-star
death is unexpectedly rich and diverse. The (heterogeneous) class of
fast blue optical transients'' (FBOT) has now established that a
large fraction of massive stars undergo significant mass losses, and
in some cases these losses serve as omens of their deaths
(supernovae). The discovery of AT2018cow (z=0.0141) established a
genuinely new type of cosmic explosion. AT2018cow was not only an FBOT
but was marked by intense X-ray emission and variability which
requires a powerful long-lived engine. Its high radio luminosity and
late millimeter peak implied dense circum-stellar medium (CSM).
Following the discovery of AT2018cow two events, ZTF18abvkwla
(z=0.271), CSS161010 (z=0.034; archival analysis), and AT2020xnd
(z=0.244) were identified. A fundamental open question is the nature
of the central engine. The X-ray band is essential since it probes
materials closest to the central power source.

Sequence Number: 503294

Title : Search for jet afterglow from a magnetar-powered X-ray transient
PI: Lin
Abstract: Chandra just serendipitously detected a fast X-ray transient on 2021
April 23. It has a special X-ray light curve of a fast rise to a
plateau lasting a few thousand seconds, followed by a steep decay,
very similar to CDF-S XT2, which was recently shown to be powered by a
magnetar formed in a binary neutron star (BNS) merger. Such a unique
signal, if confirmed, can be synthesized with gravitational wave to
probe BNS mergers and dense
matter. We request a 60 ks Chandra observation to be carried out in
one month to search for a delayed off-axis jet afterglow in order to
confirm its BNS merger nature.

Sequence Number: 402296

Title : Probing the disc-wind-jet connection in black hole transients
PI: Diaz Trigo
Abstract: We request three 50 ks observations of the candidate black hole
low-mass X-ray binary MAXI J1803-298 during the hard-to-soft state
transition with Chandra/HETGS to investigate the presence of narrow
X-ray absorption/emission features in the spectra, which are a
signature of a disc wind, and their relation to the accreting regime.
Such features, identified with ions like Fe XXV and Fe XXVI give us
information about the mass outflow rate and the launching mechanism of
the wind. With coordinated radio observations we will probe the
relationship between jet power and wind properties and how the radio
flux density correlates with the X-ray flux in different accretion
regimes.

Sequence Number: 402295

Title : Probing the disc-wind-jet connection in black hole transients
PI: Diaz Trigo
Abstract: We request three 50 ks observations of the candidate black hole
low-mass X-ray binary MAXI J1803-298 during the hard-to-soft state
transition with Chandra/HETGS to investigate the presence of narrow
X-ray absorption/emission features in the spectra, which are a
signature of a disc wind, and their relation to the accreting regime.
Such features, identified with ions like Fe XXV and Fe XXVI give us
information about the mass outflow rate and the launching mechanism of
the wind. With coordinated radio observations we will probe the
relationship between jet power and wind properties and how the radio
flux density correlates with the X-ray flux in different accretion
regimes.

Sequence Number: 402294

Title : Probing the disc-wind-jet connection in black hole transients
PI: Diaz Trigo
Abstract: We request three 50 ks observations of the candidate black hole
low-mass X-ray binary MAXI J1803-298 during the hard-to-soft state
transition with Chandra/HETGS to investigate the presence of narrow
X-ray absorption/emission features in the spectra, which are a
signature of a disc wind, and their relation to the accreting regime.
Such features, identified with ions like Fe XXV and Fe XXVI give us
information about the mass outflow rate and the launching mechanism of
the wind. With coordinated radio observations we will probe the
relationship between jet power and wind properties and how the radio
flux density correlates with the X-ray flux in different accretion
regimes.

Sequence Number: 704292

Title : A look at NGC 4151 at an exceptional flux and hardness
PI: Miller
Abstract: As of April 22, NGC 4151 is the brightest that it has been in the
Swift BAT, and today's Swift XRT snapshot records a flux 20% higher
than prior high-flux states (that are typically associated with low
BAT fluxes). Further proof of a rare accretion state and accretion
flow can be gleaned from ZTF monitoring, which finds NGC 4151 at its
brightest point for the entire monitoring period. The sensitivity and
resolution of the HETG is ideal for studying the narrow Fe K line and
disk winds. In prior published results, we showed that this line is
likely asymmetric and may arise at radii smaller than the BLR, rather
than within the BLR or torus. Whereas the equivalent width of this
line is 180 eV in prior Chandra spectra of hard states, and <100 eV in
soft states, the latest XRT snapshot suggests an equivalent width of
500-700 eV. This presents a remarkable opportunity to study the
accretion flow in this key source. We request a 50 ks obs.,
commensurate with the longest observing window.

Sequence Number: 503293

Title : Unraveling the nature of the persistent radio source associated to
FRB201124A with Chandra
PI: Piro
Abstract: FRB201124A is the second repeating fast radio burst (FRB) in which a
persistent radio source (PRS) has been very recently detected. Due to
its its closer distance (z=0.098), observations of the field of
FRB201124A can provide further insights into the nature of PRSs
associated to FRBs. Recently, multiple FRBs were detected from
FRB201124A by ASKAP, uGMRT, and the VLA. Following this, we performed
observations with the VLA and Swift/XRT. In our VLA observation, we
detect a PRS consistent with the locations reported for the VLA FRBs,
uGMRT FRBs, and uGMRT persistent radio source. Using the spectral
energy distribution for the persistent source, we determine that the
unique sensitivity of Chandra will allow us to detect the source with
high significance. This will yield a subarcsec location accuracy and a
solid association with the PRS allowing us to determine the offset of
the PRS from its galaxy and the FRB. We hereby request a 30 ks DDT
observation with Chandra to accomplish this goal.

Sequence Number: 503292

Title : CHANDRA DDT observation of the nuclear transient -
ASASSN-20hx/AT2020ohl
PI: Mandal
Abstract: ASASSN-20hx/AT2020ohl was discovered in the nearby (z=0.0167) X-ray
and radio faint, galaxy NGC 6297. The post-discovery Swift follow-up
for more than 200 days showed that the object is bright in X-ray, NUV,
with persistently bluish nature consistent with canonical TDEs,
although unlike TDEs this object has not shown any line formation in
the optical spectrum over this long duration. To identify the nature
of the source we have triggered Jansky Very Large Array (JVLA) in
X-Band (proposal ID: VLA/20B-427), and detected the high-frequency
radio counterpart at the center of the galaxy as well as another radio
source very near (~1.5'') to the center. We are now motivated to
observe the field using CHANDRA/HRC-I to find out the X-ray
association with one of these two radio-knots. Noteworthy, this field
was never imaged from CHANDRA. Here we propose for one epoch
CHANDRA/HRC-I ToO observation of the field of AT2020ohl in the highest
spatial resolution.

Sequence Number: 402293

Title : An accurate position of a new nearby ULX in NGC 4945
PI: Brightman
Abstract: On February 8th, we discovered a new ULX in the galaxy NGC 4945
(http://www.astronomerstelegram.org/?read=14380). The new ULX was
detected serendipitously in a Swift/XRT observation of the galaxy, and
no X-ray source has been reported at or near this position before
despite numerous previous Swift, Chandra, XMM-Newton, and NuSTAR
observations. We have continued to follow the source with Swift,
finding that the source continues to be active, and here we request to
follow up with a Chandra observation. The Chandra data will provide an
accurate position of the source, which will in turn allow a search for
a potential optical counterpart. We already have a candidate
counterpart in the 2.7" Swift positional error circle, but Chandra is
needed to confirm this. We request a 10-ks exposure, which is required
to detect enough X-ray sources in the field of view to carry out the
astrometric correction.

Sequence Number: 503291

Title : A Highly-Polarized, Highly-Variable Radio Source Near the Galactic
Center: A New Magnetar or Transitional MSP?
PI: Kaplan
Abstract: A highly variable radio source was discovered by ASKAP about 4 degrees
from the Galactic Center (GC) at a latitude of -0.03. Bright,
polarized emission was recently detected with MeerKAT but with large
flux variations on timescales of hours/days. The location of the
source within the plane and close to the GC along with the radio
variability/polarization point to a pulsar nature for this intriguing
object. The source might be a radio-loud magnetar or a transitional
millisecond pulsar (tMSP). In the case of a magnetar the radio
emission is always observed in connection with an X-ray outburst. If
this source is a tMSP it should be now in its ?intermediate? or
?pulsar'' state, again with predicted X-ray emission. In either
interpretation the source would be very interesting: either would be a
rare source, and both would allow important constraints on the pulsar
progenitors and population in that region.

Sequence Number: 503290

Title : Afterglow identification for short GRB 190610A
PI: Tohuvavohu
Abstract: GRB 190610A is a short hard burst discovered and localized by
Swift/BAT. The BAT localization is consistent with a nearby galaxy at
~165 Mpc. XRT follow-up observations yielded an afterglow candidate,
below existing upper limits. Due to the source's faintness a
determination of fading and the confident afterglow identification to
distinguish this from a possible contaminating background source
cannot be made with XRT. We request a late-time Chandra observation of
this XRT afterglow candidate, to help determine whether this burst is
a member of an extremely rare class of local, nearly on-axis, neutron
star mergers within the GW detector horizon.

Sequence Number: 704287

Title : Resolving the Flaring Site of PKS 1127-145 jet
PI: Siemiginowska
Abstract: On December 11, 2020 the Fermi-LAT Collaboration reported a strong
gamma-ray flare associated with the flat spectrum radio loud quasar
PKS 1127-145 at redshift z=1.184. This is the first strong gamma-ray
flaring activity observed from this source in the Fermi era with the
highest gamma-ray flux ever detected in this quasar, a factor of 50
higher than the average flux estimated in the 4FGL catalogue. This is
the first opportunity for Chandra to observe this quasar in an active
state. The Chandra observation will provide the required arcsec
resolution to confirm that the gamma-ray flare is associated with this
quasar and to locate the site of the flare.

Sequence Number: 503289

Title : GRB201214B: an off-axis burst in the nearby universe?
PI: Troja
Abstract: GRB201214B is a weak gamma-ray burst discovered by Fermi GBM and
localized by Swift BAT close to a nearby galaxy at D~280 Mpc. XRT
follow-up observations do not identify any counterpart within the BAT
error region, showing that this event is not associated with a bright
X-ray afterglow. Its weak gamma-ray signal, lack of early X-ray
emission and possible association with a nearby galaxy are reminiscent
of GRB150101B and GW170817, two off-axis afterglows detected by
Chandra. If GRB201214B is a similar explosion seen off-axis, its
afterglow would slowly rise and peak several days/weeks after the GRB.
We therefore request a pair of Chandra observations to search for the
onset of a delayed X-ray afterglow, and test whether this GRB heralds
a rare neutron star merger in the nearby universe.

Sequence Number: 503288

Title : GRB201214B: an off-axis burst in the nearby universe?
PI: Troja
Abstract: GRB201214B is a weak gamma-ray burst discovered by Fermi GBM and
localized by Swift BAT close to a nearby galaxy at D~280 Mpc. XRT
follow-up observations do not identify any counterpart within the BAT
error region, showing that this event is not associated with a bright
X-ray afterglow. Its weak gamma-ray signal, lack of early X-ray
emission and possible association with a nearby galaxy are reminiscent
of GRB150101B and GW170817, two off-axis afterglows detected by
Chandra. If GRB201214B is a similar explosion seen off-axis, its
afterglow would slowly rise and peak several days/weeks after the GRB.
We therefore request a pair of Chandra observations to search for the
onset of a delayed X-ray afterglow, and test whether this GRB heralds
a rare neutron star merger in the nearby universe.

Sequence Number: 704286

Title : The recurring rebrightening of ESO253-G003
PI: Payne
Abstract: We discovered highly atypical flares within the AGN ESO253-G003 that
are periodic with a non-zero negative period derivative (Payne et al.
2020). These outburst events have occurred predictably for the last
six years. Numerous rebrightening events are highly unusual for an
AGN, which normally vary at a low-level following a damped random walk
model. The precise origin of these flares remains unknown but they
could be caused by a repeating partial tidal disruption event (TDE).
Studying this object will provide new and distinctive insights into
the mechanisms driving this transient and the broader inner workings
of AGN variability.

Sequence Number: 704285

Title : The recurring rebrightening of ESO253-G003
PI: Payne
Abstract: We discovered highly atypical flares within the AGN ESO253-G003 that
are periodic with a non-zero negative period derivative (Payne et al.
2020). These outburst events have occurred predictably for the last
six years. Numerous rebrightening events are highly unusual for an
AGN, which normally vary at a low-level following a damped random walk
model. The precise origin of these flares remains unknown but they
could be caused by a repeating partial tidal disruption event (TDE).
Studying this object will provide new and distinctive insights into
the mechanisms driving this transient and the broader inner workings
of AGN variability.

Sequence Number: 100204

Title : On the shoulders of Gas Giants: Observing Saturn's X-rays with a
varying external driver
PI: Weigt
Abstract: In November 2020, the planets Jupiter and Saturn will be in unique
alignment: Saturn will be immersed in Jupiter's magnetotail. This only
occurs once in every 19 years and is unique to the gas giants. Voyager
2 ~40 years ago found the environment at Saturn during this time was a
variable parameter space and found the (magneto-)tail of Jupiter to
flap, without any coincident remote sensing or X-ray data. This caused
Saturn to be alternately every 2-3 days immersed in the rarefied tail
and then denser solar wind. These changes are likely to produce shocks
as the magnetosphere compresses and expands in response to changing
pressure and dynamics, brightening the aurora. However, there are
still many unknowns about how Saturn's auroral/disk emissions will
respond to no solar wind drivers.

Therefore, we propose to observe Saturn?s X-rays in this unique
unknown parameter space for the first time. The data provided will aid
the ongoing multiwavelength campaign, exploring Saturn's response.

Sequence Number: 100204

Title : On the shoulders of Gas Giants: Observing Saturn's X-rays with a
varying external driver
PI: Weigt
Abstract: In November 2020, the planets Jupiter and Saturn will be in unique
alignment: Saturn will be immersed in Jupiter's magnetotail. This only
occurs once in every 19 years and is unique to the gas giants. Voyager
2 ~40 years ago found the environment at Saturn during this time was a
variable parameter space and found the (magneto-)tail of Jupiter to
flap, without any coincident remote sensing or X-ray data. This caused
Saturn to be alternately every 2-3 days immersed in the rarefied tail
and then denser solar wind. These changes are likely to produce shocks
as the magnetosphere compresses and expands in response to changing
pressure and dynamics, brightening the aurora. However, there are
still many unknowns about how Saturn's auroral/disk emissions will
respond to no solar wind drivers.

Therefore, we propose to observe Saturn?s X-rays in this unique
unknown parameter space for the first time. The data provided will aid
the ongoing multiwavelength campaign, exploring Saturn's response.

Sequence Number: 100204

Title : On the shoulders of Gas Giants: Observing Saturn's X-rays with a
varying external driver
PI: Weigt
Abstract: In November 2020, the planets Jupiter and Saturn will be in unique
alignment: Saturn will be immersed in Jupiter's magnetotail. This only
occurs once in every 19 years and is unique to the gas giants. Voyager
2 ~40 years ago found the environment at Saturn during this time was a
variable parameter space and found the (magneto-)tail of Jupiter to
flap, without any coincident remote sensing or X-ray data. This caused
Saturn to be alternately every 2-3 days immersed in the rarefied tail
and then denser solar wind. These changes are likely to produce shocks
as the magnetosphere compresses and expands in response to changing
pressure and dynamics, brightening the aurora. However, there are
still many unknowns about how Saturn's auroral/disk emissions will
respond to no solar wind drivers.

Therefore, we propose to observe Saturn?s X-rays in this unique
unknown parameter space for the first time. The data provided will aid
the ongoing multiwavelength campaign, exploring Saturn's response.

Sequence Number: 503287

Title : CHANDRA OBSERVATIONS OF A NEW SGR 1830-0645
PI: Kouveliotou
Abstract: Swift/BAT has discovered a magnetar-like soft (<50 keV) X-ray burst
(duration <0.1s) potentially from as new magnetar source, SGR
1830-0645 (GCN 28594). We would like to request a 10ks DDT observation
of this new source with HRC to determine an accurate position and
timing of its persistent emission. We intend, thereafter, to follow up
the source with XMM-Newton, and further determine its spectral and
timing properties. The magnetar population in our Galaxy is very small
(~30 sources) - this discovery will significantly, therefore,
increase this population and needs to be well studied. Further, the
source resides in a very dense area of the Galactic Plane (which
already hosts several magnetars) and HRC is the only instrument that
can locate it with great accuracy, so that we can have radio and
optical followup observations.

Sequence Number: 704283

Title : Resolving RXJ1756 with Chandra: A Recoiling Black Hole Candidate or
Possible Triple AGN
PI: Koss
Abstract: The coalescence of binary supermassive black holes in galaxy mergers
is thought to constitute the strongest source of gravitational waves.
Theory suggests these waves carry momentum causing the merged SMBH to
experience a velocity recoil or kick that displaces or may even eject
it from the center of its host galaxy. Despite their importance, only
a few spatially or kinematically offset recoiling BH candidates are
known, and none has been confirmed with extensive multiwavelength
observing. We request DDT time to follow-up a very recent 2020 Aug 2
HST, XMM-Newton, and NuSTAR
observations of an extremely puzzling source RXJ1756.4+5235, a
recoiling supermassive black hole candidate or possible triple AGN.

Sequence Number: 704254

Title : A dramatic change in an agn
PI: Miller
Abstract: A full science justification has been sent to the director in a
separate email.

Sequence Number: 704254

Title : A dramatic change in an agn
PI: Miller
Abstract: A full science justification has been sent to the director in a
separate email.

Sequence Number: 704254

Title : A dramatic change in an agn
PI: Miller
Abstract: A full science justification has been sent to the director in a
separate email.

Sequence Number: 704254

Title : A dramatic change in an agn
PI: Miller
Abstract: A full science justification has been sent to the director in a
separate email.

Sequence Number: 402282

Title : Chandra observation of the mysterious X-ray transient AT2019wey/SRG
PI: Kulkarni
Abstract: AT2019wey/SRG though discovered in December 2019 only rose to
prominence with the discovery of strong X-ray emission by the
Spectrum-Roentgen-Gamma (SRG) mission in March, 2020. The source was
not present in any historical optical sky surveys nor Rosat All Sky
survey, though it was detected at 17.5 mag and few mCrab just from
this year. The unusual nature of this Galactic source (various H and
He lines at z=0) led to generous allocation of Swift, NICER, and
NuSTAR monitoring time. The detection of relativistic reflection from
NuSTAR and the detection of radio emission from VLA, taken together,
suggest that the source is likely an accreting stellar black hole.
The long 'on state' is unprecedented for a low mass accreting black
hole binary.

We propose a Chandra HETG exploratory observation to detect possible
narrow line iron components and also spectrally resolve the low
energy (<1 keV) hump. These may provide new insights into the nature
of this mysterious transient.

Sequence Number: 704251

Title : Follow up a special hard tidal disruption event
PI: Lin
Abstract: We just discover a remarkable UV/X-ray outburst from Swift in our
archival data search. Because it is positionally coincident with the
nucleus of a nearby inactive galaxy at z=0.026, it is a strong tidal
disruption event (TDE) candidate. It is remarkable in three aspects:
(1) a well covered UV/X-ray light curve constraining the outburst
start time to within two weeks; (2) hard X-ray spectra (powerlaw
photon index 1.8-2.5) seen in only a few TDEs; (3) a surprising fast
rebrightening (by one order of magnitude and last for one month) in
X-rays but not in the UV during the overall decay. We now request a
Chandra observation to confirm the nuclear origin of the event, to
confirm the hardening of the X-ray spectra, as part of our long-term
campaign, to constrain the long-tern evolution of the X-ray emission.

Sequence Number: 503278

Title : Chandra observations of PSR J1846-0258 in outburst
PI: Blumer
Abstract: PSR J1846-0258 (J1846), powering a bright and compact pulsar wind
nebula (PWN) in the young supernova remnant Kes 75, was the first
high-magnetic (B) field pulsar to display a magnetar-like behavior in
2006, blurring the distinction between rotation-powered pulsars and
magnetars. Chandra observations of J1846 performed 7 days past the
outburst activity revealed that the pulsar brightened (by a factor of
6 times) and its spectrum softened significantly such that it became
reminiscent of those observed from magnetars. Subsequent observations
in 2009 revealed that the pulsar had gone back to quiescence. J1846
has entered into a new state of activity on 1 Aug 2020, emitting a
short burst detected with Swift. We request a prompt follow up
observation with Chandra to study its magnetar-like behavior in
comparison with the 2006 bursts, and to search for any PWN variability
associated with the burst.

Sequence Number: 402198

Title : Investigating the vertical structure of the disc wind in Her X-1
PI: Kosec
Abstract: Hercules X-1 is a unique neutron star X-ray binary system showing a
periodically precessing warped accretion disc. At the same time, it
exhibits a varying accretion disc wind. The variations are likely
driven by the disc precession and correspond to our observations
sampling different lines of sight above the warped disc, thus allowing
us to study the vertical disc wind structure. Our coordinated
XMM-Newton, NuSTAR and INTEGRAL campaign will observe a large part of
a single precession cycle of Her X-1, finely sampling the wind
structure, accurately measuring its total mass outflow rate and
shedding light on its launching mechanism. A simultaneous Chandra HETG
observation would greatly complement this dataset. It could fill-in
one of the XMM orbital gaps, expanding our time-resolved wind
parameter study. Additionally, it would allow us to cross-check the
wind parameters derived from XMM data, and to perform a full chemical
abundance study of the disc wind.

Sequence Number: 402198

Title : Investigating the vertical structure of the disc wind in Her X-1
PI: Kosec
Abstract: Hercules X-1 is a unique neutron star X-ray binary system showing a
periodically precessing warped accretion disc. At the same time, it
exhibits a varying accretion disc wind. The variations are likely
driven by the disc precession and correspond to our observations
sampling different lines of sight above the warped disc, thus allowing
us to study the vertical disc wind structure. Our coordinated
XMM-Newton, NuSTAR and INTEGRAL campaign will observe a large part of
a single precession cycle of Her X-1, finely sampling the wind
structure, accurately measuring its total mass outflow rate and
shedding light on its launching mechanism. A simultaneous Chandra HETG
observation would greatly complement this dataset. It could fill-in
one of the XMM orbital gaps, expanding our time-resolved wind
parameter study. Additionally, it would allow us to cross-check the
wind parameters derived from XMM data, and to perform a full chemical
abundance study of the disc wind.

Sequence Number: 503207

Title : X-ray observations of a candidate Pulsar Wind Nebula
PI: MARGUTTI
Abstract: We propose to re-observe the energetic SN2012au with Chandra. SN2012au
showed evidence for a remarkable radio re brightening (accompanied by
a radio spectrum inversion at GHz frequencies). Here we ask for deep
X-ray observations of SN2012au to constrain the high-energy part of
the spectrum and constrain the physical parameters.

Sequence Number: 503207

Title : X-ray observations of a candidate Pulsar Wind Nebula
PI: MARGUTTI
Abstract: We propose to re-observe the energetic SN2012au with Chandra. SN2012au
showed evidence for a remarkable radio re brightening (accompanied by
a radio spectrum inversion at GHz frequencies). Here we ask for deep
X-ray observations of SN2012au to constrain the high-energy part of
the spectrum and constrain the physical parameters.

Sequence Number: 503206

Title : X-ray Progenitor Constraints of the Subluminous Type Ia SN2020nlb
PI: Sand
Abstract: SN2020nlb is a newly discovered subluminous type Ia SN in the nearby
galaxy M85 (D~15 Mpc), found within two days of explosion. While it
is accepted that SNe Ia are the thermonuclear explosions of CO white
dwarfs, it is still unclear by what mechanisms the white dwarf gains
the necessary mass and how it then explodes. Deep X-ray observations
provide critical information on SN Ia progenitors as a probe of the
circumstellar material they left behind. SN2020nlb would represent
the first subluminous SN Ia with deep CSM limits in the X-ray, and may
lead to the first definitive detection!

Sequence Number: 503206

Title : X-ray Progenitor Constraints of the Subluminous Type Ia SN2020nlb
PI: Sand
Abstract: SN2020nlb is a newly discovered subluminous type Ia SN in the nearby
galaxy M85 (D~15 Mpc), found within two days of explosion. While it
is accepted that SNe Ia are the thermonuclear explosions of CO white
dwarfs, it is still unclear by what mechanisms the white dwarf gains
the necessary mass and how it then explodes. Deep X-ray observations
provide critical information on SN Ia progenitors as a probe of the
circumstellar material they left behind. SN2020nlb would represent
the first subluminous SN Ia with deep CSM limits in the X-ray, and may
lead to the first definitive detection!

Sequence Number: 704049

Title : INVESTIGATION ON MRK 335 IN AN INTERMEDIATE STATE
PI: Boissay-Malaquin
Abstract: We propose a DDT observation of the highly variable Narrow-Line
Seyfert 1 Mrk 335 with Chandra/HETG (150 ks DDT + 90 ks GTO). Because
of a pending observation accepted for cycle 5, NuSTAR will join such
Chandra observation on a best effort basis. We also seek to obtain a
contemporaneous NICER DDT observation. We aim to characterize the warm
absorbers previously detected in XMM-Newton/RGS data. We aim to
observe Mrk 335 in the next 10-20 days, while it has an intermediate
flux, ideal state for the detection of the absorbers. Observing now
ensures that we will catch the adequate intermediate state (according
to the Swift monitoring), but also offers a unique view of an AGN when
it is turning on again, after being in a low flux state for the past 2
years. These observations will provide high-resolution spectra that
will allow us to deconvolve and constrain the primary continuum, the
multiple absorbers, the narrow and broad iron lines, the local and
distant reflections and the soft excess.

Sequence Number: 704049

Title : INVESTIGATION ON MRK 335 IN AN INTERMEDIATE STATE
PI: Boissay-Malaquin
Abstract: We propose a DDT observation of the highly variable Narrow-Line
Seyfert 1 Mrk 335 with Chandra/HETG (150 ks DDT + 90 ks GTO). Because
of a pending observation accepted for cycle 5, NuSTAR will join such
Chandra observation on a best effort basis. We also seek to obtain a
contemporaneous NICER DDT observation. We aim to characterize the warm
absorbers previously detected in XMM-Newton/RGS data. We aim to
observe Mrk 335 in the next 10-20 days, while it has an intermediate
flux, ideal state for the detection of the absorbers. Observing now
ensures that we will catch the adequate intermediate state (according
to the Swift monitoring), but also offers a unique view of an AGN when
it is turning on again, after being in a low flux state for the past 2
years. These observations will provide high-resolution spectra that
will allow us to deconvolve and constrain the primary continuum, the
multiple absorbers, the narrow and broad iron lines, the local and
distant reflections and the soft excess.

Sequence Number: 704049

Title : INVESTIGATION ON MRK 335 IN AN INTERMEDIATE STATE
PI: Boissay-Malaquin
Abstract: We propose a DDT observation of the highly variable Narrow-Line
Seyfert 1 Mrk 335 with Chandra/HETG (150 ks DDT + 90 ks GTO). Because
of a pending observation accepted for cycle 5, NuSTAR will join such
Chandra observation on a best effort basis. We also seek to obtain a
contemporaneous NICER DDT observation. We aim to characterize the warm
absorbers previously detected in XMM-Newton/RGS data. We aim to
observe Mrk 335 in the next 10-20 days, while it has an intermediate
flux, ideal state for the detection of the absorbers. Observing now
ensures that we will catch the adequate intermediate state (according
to the Swift monitoring), but also offers a unique view of an AGN when
it is turning on again, after being in a low flux state for the past 2
years. These observations will provide high-resolution spectra that
will allow us to deconvolve and constrain the primary continuum, the
multiple absorbers, the narrow and broad iron lines, the local and
distant reflections and the soft excess.

Sequence Number: 704049

Title : INVESTIGATION ON MRK 335 IN AN INTERMEDIATE STATE
PI: Boissay-Malaquin
Abstract: We propose a DDT observation of the highly variable Narrow-Line
Seyfert 1 Mrk 335 with Chandra/HETG (150 ks DDT + 90 ks GTO). Because
of a pending observation accepted for cycle 5, NuSTAR will join such
Chandra observation on a best effort basis. We also seek to obtain a
contemporaneous NICER DDT observation. We aim to characterize the warm
absorbers previously detected in XMM-Newton/RGS data. We aim to
observe Mrk 335 in the next 10-20 days, while it has an intermediate
flux, ideal state for the detection of the absorbers. Observing now
ensures that we will catch the adequate intermediate state (according
to the Swift monitoring), but also offers a unique view of an AGN when
it is turning on again, after being in a low flux state for the past 2
years. These observations will provide high-resolution spectra that
will allow us to deconvolve and constrain the primary continuum, the
multiple absorbers, the narrow and broad iron lines, the local and
distant reflections and the soft excess.

Sequence Number: 704049

Title : INVESTIGATION ON MRK 335 IN AN INTERMEDIATE STATE
PI: Boissay-Malaquin
Abstract: We propose a DDT observation of the highly variable Narrow-Line
Seyfert 1 Mrk 335 with Chandra/HETG (150 ks DDT + 90 ks GTO). Because
of a pending observation accepted for cycle 5, NuSTAR will join such
Chandra observation on a best effort basis. We also seek to obtain a
contemporaneous NICER DDT observation. We aim to characterize the warm
absorbers previously detected in XMM-Newton/RGS data. We aim to
observe Mrk 335 in the next 10-20 days, while it has an intermediate
flux, ideal state for the detection of the absorbers. Observing now
ensures that we will catch the adequate intermediate state (according
to the Swift monitoring), but also offers a unique view of an AGN when
it is turning on again, after being in a low flux state for the past 2
years. These observations will provide high-resolution spectra that
will allow us to deconvolve and constrain the primary continuum, the
multiple absorbers, the narrow and broad iron lines, the local and
distant reflections and the soft excess.

Sequence Number: 704048

Title : Detecting the softening of emission in quiescence in a supermassive
black hole
PI: Wevers
Abstract: Tidal disruptions of stars by supermassive black holes (SMBHs) have
long been proposed as probes of accretion state transitions around
SMBHs. However, due to a combination of lack of accurate physical
models and dedicated X-ray (corona) and UV (disk) monitoring programs,
such events have not yet been identified. We have been tracking the
first such case over the last 600+ days using the X-ray and UV data
from Swift, NICER, and XMM-Newton (see Fig. 1 of science
justification). During this time the source underwent two state
transitions, the only known SMBH to undergo such extreme and rapid
accretion regime changes, and now it is approaching a quiescent state.
Here, we propose for a 50 ks Chandra exposure, an estimated factor of
10 deeper than a recent XMM observation, to test various (currently
unconstrained) models of accretion physics.

Sequence Number: 503205

Title : Unpicking the threads of a rare collapsar explosion
PI: Troja
Abstract: GRB190829A is a rare nearby (z=0.08) gamma-ray burst of long duration,
followed by a bright Type Ic supernova. Recently it was proposed that
events like GRB190829A could produce large amounts of heavy metals,
and be the dominant sources of galactic r-process enrichment . The
characteristic signature would be a long-lived infrared emission,
outshining the supernova light months after the explosion. The main
obstacle in identifying this novel emission component is the bright
GRB afterglow. Continued X-ray monitoring of this GRB would
characterize its non-thermal emission, and allow us to disentangle the
afterglow contribution from any possible red excess. Only Chandra can
resolve the GRB counterpart from nearby contaminating sources.

Sequence Number: 402197

Title : Get to the Chopper!!! - Testing the Propeller Nature of the Off-States
in the ULX Pulsar NGC7793 P13
PI: Walton
Abstract: NGC7793 P13, one of the few ULXs known to be powered by a neutron
star, has recently entered an 'off-state' (i.e its flux is >10x below
its 'normal' ULX level). These may be related to the propeller effect,
and may offer an opportunity to determine the B-field (still hotly
debated). Based on its previous off-state (0.3-10 keV flux of ~3-6e-14
erg/cm^2/s), simulations suggest that a deep observation with XMM
could still detect pulsations if they are present, allowing us to
probe the nature of these rare and potentially key events. In order to
determine whether this is feasible for the new off-state we need to
confirm the current flux of the source, but this is now below the
detection capabilities of Swift. We are therefore requesting a short
DDT observation with Chandra. In addition, the excellent spatial
resolution will allow us to test whether the emission is point-like or
extended, following the detection of extended emission in an off-state
seen from the ULX pulsar NGC5907 ULX1.

Sequence Number: 503204

Title : Light echoes from the magnetar, SGR J1935+2154
PI: Gogus
Abstract: SGR 1935+2154 is one of the most burst prolific transient magnetars:
It was discovered in 2014 with Swift-BAT after emitting short duration
magnetar-like bursts, and exhibited three activity episodes in 2016,
2017, 2019 and a fourth one, which started a day ago. More than 35
bursts were recorded from the source in the last 24 hours (ATel 13675:
Palmer et al. 2020, GCN 27657: Barthelmy et al., 2020), MAXI (GCN
27661: Sugawara, Y. et al., 2020) as well as Fermi (GCN 27659:
Fletcher, C. et al., 2020) and Calet GBM (GCN 27663: Ricciarini et al.
2020). Swift XRT has also collected data in PC mode for about 2 ks in
response to the Swift trigger (#968211). We clearly detect an X-ray
ring around the source in this short exposure. The emission around the
source is also quite extended, reaching to about 0.5'. We propose a 10
ks pointing with ACIS-I to explore the ring, search for other rings
and a possible wind nebula powered by the magnetar.

Sequence Number: 100193

Title : Grating spectroscopy of the unexpectedly bright comet C/2019 Y4 ATLAS
PI: Bodewits
Abstract: Our observations will also allow us to study the temporal development
of the X-ray emission from Comet ATLAS under its rapidly changing
conditions. ATLAS is an Oort cloud comet discovered in December 2019
(MPEC 2020-A112). Based on its current brightness and behavior, it is
expected to become a naked-eye object in May and possibly the
brightest comet seen in the last decade. This provides a unique
opportunity to observe the comet with the Chandra gratings to acquire
a high resolution X-ray spectrum that allows us to resolve the low
energy line emission (< 300eV; Snios et al. 2016), to test new
theories about how solar wind charge exchange emission lines ratios
are affected by the composition of the neutral gas around comets
(Mullen et al. 2017), and to investigate the curious lines in the 1 to
2 keV region (Ewing et al. 2013).

Sequence Number: 100193

Title : Grating spectroscopy of the unexpectedly bright comet C/2019 Y4 ATLAS
PI: Bodewits
Abstract: Our observations will also allow us to study the temporal development
of the X-ray emission from Comet ATLAS under its rapidly changing
conditions. ATLAS is an Oort cloud comet discovered in December 2019
(MPEC 2020-A112). Based on its current brightness and behavior, it is
expected to become a naked-eye object in May and possibly the
brightest comet seen in the last decade. This provides a unique
opportunity to observe the comet with the Chandra gratings to acquire
a high resolution X-ray spectrum that allows us to resolve the low
energy line emission (< 300eV; Snios et al. 2016), to test new
theories about how solar wind charge exchange emission lines ratios
are affected by the composition of the neutral gas around comets
(Mullen et al. 2017), and to investigate the curious lines in the 1 to
2 keV region (Ewing et al. 2013).

Sequence Number: 100193

Title : Grating spectroscopy of the unexpectedly bright comet C/2019 Y4 ATLAS
PI: Bodewits
Abstract: Our observations will also allow us to study the temporal development
of the X-ray emission from Comet ATLAS under its rapidly changing
conditions. ATLAS is an Oort cloud comet discovered in December 2019
(MPEC 2020-A112). Based on its current brightness and behavior, it is
expected to become a naked-eye object in May and possibly the
brightest comet seen in the last decade. This provides a unique
opportunity to observe the comet with the Chandra gratings to acquire
a high resolution X-ray spectrum that allows us to resolve the low
energy line emission (< 300eV; Snios et al. 2016), to test new
theories about how solar wind charge exchange emission lines ratios
are affected by the composition of the neutral gas around comets
(Mullen et al. 2017), and to investigate the curious lines in the 1 to
2 keV region (Ewing et al. 2013).

Sequence Number: 100193

Title : Grating spectroscopy of the unexpectedly bright comet C/2019 Y4 ATLAS
PI: Bodewits
Abstract: Our observations will also allow us to study the temporal development
of the X-ray emission from Comet ATLAS under its rapidly changing
conditions. ATLAS is an Oort cloud comet discovered in December 2019
(MPEC 2020-A112). Based on its current brightness and behavior, it is
expected to become a naked-eye object in May and possibly the
brightest comet seen in the last decade. This provides a unique
opportunity to observe the comet with the Chandra gratings to acquire
a high resolution X-ray spectrum that allows us to resolve the low
energy line emission (< 300eV; Snios et al. 2016), to test new
theories about how solar wind charge exchange emission lines ratios
are affected by the composition of the neutral gas around comets
(Mullen et al. 2017), and to investigate the curious lines in the 1 to
2 keV region (Ewing et al. 2013).

Sequence Number: 100193

Title : Grating spectroscopy of the unexpectedly bright comet C/2019 Y4 ATLAS
PI: Bodewits
Abstract: Our observations will also allow us to study the temporal development
of the X-ray emission from Comet ATLAS under its rapidly changing
conditions. ATLAS is an Oort cloud comet discovered in December 2019
(MPEC 2020-A112). Based on its current brightness and behavior, it is
expected to become a naked-eye object in May and possibly the
brightest comet seen in the last decade. This provides a unique
opportunity to observe the comet with the Chandra gratings to acquire
a high resolution X-ray spectrum that allows us to resolve the low
energy line emission (< 300eV; Snios et al. 2016), to test new
theories about how solar wind charge exchange emission lines ratios
are affected by the composition of the neutral gas around comets
(Mullen et al. 2017), and to investigate the curious lines in the 1 to
2 keV region (Ewing et al. 2013).

Sequence Number: 100193

Title : Grating spectroscopy of the unexpectedly bright comet C/2019 Y4 ATLAS
PI: Bodewits
Abstract: Our observations will also allow us to study the temporal development
of the X-ray emission from Comet ATLAS under its rapidly changing
conditions. ATLAS is an Oort cloud comet discovered in December 2019
(MPEC 2020-A112). Based on its current brightness and behavior, it is
expected to become a naked-eye object in May and possibly the
brightest comet seen in the last decade. This provides a unique
opportunity to observe the comet with the Chandra gratings to acquire
a high resolution X-ray spectrum that allows us to resolve the low
energy line emission (< 300eV; Snios et al. 2016), to test new
theories about how solar wind charge exchange emission lines ratios
are affected by the composition of the neutral gas around comets
(Mullen et al. 2017), and to investigate the curious lines in the 1 to
2 keV region (Ewing et al. 2013).

Sequence Number: 100193

Title : Grating spectroscopy of the unexpectedly bright comet C/2019 Y4 ATLAS
PI: Bodewits
Abstract: Our observations will also allow us to study the temporal development
of the X-ray emission from Comet ATLAS under its rapidly changing
conditions. ATLAS is an Oort cloud comet discovered in December 2019
(MPEC 2020-A112). Based on its current brightness and behavior, it is
expected to become a naked-eye object in May and possibly the
brightest comet seen in the last decade. This provides a unique
opportunity to observe the comet with the Chandra gratings to acquire
a high resolution X-ray spectrum that allows us to resolve the low
energy line emission (< 300eV; Snios et al. 2016), to test new
theories about how solar wind charge exchange emission lines ratios
are affected by the composition of the neutral gas around comets
(Mullen et al. 2017), and to investigate the curious lines in the 1 to
2 keV region (Ewing et al. 2013).

Sequence Number: 100193

Title : Grating spectroscopy of the unexpectedly bright comet C/2019 Y4 ATLAS
PI: Bodewits
Abstract: Our observations will also allow us to study the temporal development
of the X-ray emission from Comet ATLAS under its rapidly changing
conditions. ATLAS is an Oort cloud comet discovered in December 2019
(MPEC 2020-A112). Based on its current brightness and behavior, it is
expected to become a naked-eye object in May and possibly the
brightest comet seen in the last decade. This provides a unique
opportunity to observe the comet with the Chandra gratings to acquire
a high resolution X-ray spectrum that allows us to resolve the low
energy line emission (< 300eV; Snios et al. 2016), to test new
theories about how solar wind charge exchange emission lines ratios
are affected by the composition of the neutral gas around comets
(Mullen et al. 2017), and to investigate the curious lines in the 1 to
2 keV region (Ewing et al. 2013).

Sequence Number: 100193

Title : Grating spectroscopy of the unexpectedly bright comet C/2019 Y4 ATLAS
PI: Bodewits
Abstract: Our observations will also allow us to study the temporal development
of the X-ray emission from Comet ATLAS under its rapidly changing
conditions. ATLAS is an Oort cloud comet discovered in December 2019
(MPEC 2020-A112). Based on its current brightness and behavior, it is
expected to become a naked-eye object in May and possibly the
brightest comet seen in the last decade. This provides a unique
opportunity to observe the comet with the Chandra gratings to acquire
a high resolution X-ray spectrum that allows us to resolve the low
energy line emission (< 300eV; Snios et al. 2016), to test new
theories about how solar wind charge exchange emission lines ratios
are affected by the composition of the neutral gas around comets
(Mullen et al. 2017), and to investigate the curious lines in the 1 to
2 keV region (Ewing et al. 2013).

Sequence Number: 503203

Title : Chandra observations of the newly discovered magnetar Swift
J1818.0-1607
PI: Blumer
Abstract: Magnetars are young neutron stars believed to be powered by their
super-strong magnetic fields and exhibiting a diverse set of
observational properties. They go through long periods of quiescence,
interrupted by bursting activity over the course of days to months
that are followed by spectral and temporal changes. Magnetar activity
has also been recently observed in other pulsar classes. In this
proposal, we request Chandra observations of Swift J1818.0-1607, a
magnetar candidate discovered by Swift on 12 March 2020 and having a
1.36-s periodicity discovered by follow-up NICER observations. The
main scientific goals here are to detect and localize the X-ray
source, constrain its imaging and spectral properties, and confirm the
magnetar nature by studying its spectrum in comparison to other
magnetars. If detected in this DDT, we will separately propose for
follow-up and more detailed X-ray studies of this source.

Sequence Number: 300469

Title : Proof of concept for the detection of non-burning symbiotic binaries
PI: Lucy
Abstract: Non-burning symbiotic binaries--powered by the accretion of a cool
giant onto a white dwarf (WD), without shell burning on the WD--are
extremely difficult to find, which is why less than 5% of known
symbiotic stars are non-burning. But the true population of
non-burning symbiotics is likely much larger, and may hold the key to
testing how the large disks of symbiotics drive jets and winds. In
this PhD thesis work, we developed a novel strategy for finding
non-burning symbiotics using uvg colors and minutes-timescale
variability in SkyMapper. In 2019 Sep-Oct, we obtained Swift followup
observations of our top two non-burning symbiotic candidates, IRAS
15175-4508 and Haro 1-10, showing a 2sig X-ray detection and 4sig UV
flickering, respectively. We request Chandra observations of IRAS
15175-4508 and Haro 1-10 to confirm the presence of their accretion
disks before their high states end, and to validate our method of
uncovering this hidden population of supernova progenitor candidates.

Sequence Number: 300468

Title : Proof of concept for the detection of non-burning symbiotic binaries
PI: Lucy
Abstract: Non-burning symbiotic binaries--powered by the accretion of a cool
giant onto a white dwarf (WD), without shell burning on the WD--are
extremely difficult to find, which is why less than 5% of known
symbiotic stars are non-burning. But the true population of
non-burning symbiotics is likely much larger, and may hold the key to
testing how the large disks of symbiotics drive jets and winds. In
this PhD thesis work, we developed a novel strategy for finding
non-burning symbiotics using uvg colors and minutes-timescale
variability in SkyMapper. In 2019 Sep-Oct, we obtained Swift followup
observations of our top two non-burning symbiotic candidates, IRAS
15175-4508 and Haro 1-10, showing a 2sig X-ray detection and 4sig UV
flickering, respectively. We request Chandra observations of IRAS
15175-4508 and Haro 1-10 to confirm the presence of their accretion
disks before their high states end, and to validate our method of
uncovering this hidden population of supernova progenitor candidates.

Sequence Number: 503202

Title : A Candidate Low-luminosity Gamma-ray Burst Identified by an Early
Optical Flash
PI: Ho
Abstract: Low-luminosity gamma-ray bursts (LLGRBs) are a rare class of
explosions with a relativistic energy release 2-3 orders of magnitude
smaller than that from classical GRBs. Due to their lower luminosities
they are only discovered nearby (z<0.1), so despite being 100x more
common than classical GRBs only seven have ever been discovered and
their origins remain unknown.

All LLGRBs are accompanied by a Type Ic-BL supernova (SN). Two events
(GRB060218/SN2006aj, GRB100316D/SN2010bh) have Chandra observations
from 10 to 40 days post-explosion that reveal an excess of soft X-ray
emission that may arise from a long-lived central engine such as an
accreting black hole or a magnetar. Early optical observations of
SN2006aj revealed a fast (<2d) blue flash prior to the onset of the
SN.

SN2020bvc (z=0.025) is a Ic-BL with an early blue flash similar to
SN2006aj (Astronote #2020-37). We propose Chandra observations to test
whether there is relativistic ejecta and compare this event to other
LLGRBs.

Sequence Number: 503201

Title : A Candidate Low-luminosity Gamma-ray Burst Identified by an Early
Optical Flash
PI: Ho
Abstract: Low-luminosity gamma-ray bursts (LLGRBs) are a rare class of
explosions with a relativistic energy release 2-3 orders of magnitude
smaller than that from classical GRBs. Due to their lower luminosities
they are only discovered nearby (z<0.1), so despite being 100x more
common than classical GRBs only seven have ever been discovered and
their origins remain unknown.

All LLGRBs are accompanied by a Type Ic-BL supernova (SN). Two events
(GRB060218/SN2006aj, GRB100316D/SN2010bh) have Chandra observations
from 10 to 40 days post-explosion that reveal an excess of soft X-ray
emission that may arise from a long-lived central engine such as an
accreting black hole or a magnetar. Early optical observations of
SN2006aj revealed a fast (<2d) blue flash prior to the onset of the
SN.

SN2020bvc (z=0.025) is a Ic-BL with an early blue flash similar to
SN2006aj (Astronote #2020-37). We propose Chandra observations to test
whether there is relativistic ejecta and compare this event to other
LLGRBs.

Sequence Number: 201344

Title : The Dimming of Betelgeuse
PI: Kashyap
Abstract: Betelgeuse (M2Iab) is a prime candidate for an impending supernova. It
has been exhibiting an unprecedented dimming (Guinan & Wasatonic, ATEL
13410), dropping in luminosity by ~25% since Sep 2019. Prima facie
this cannot be attributed to adiabatic upwelling of higher temperature
material which explains its usual variability (see Dolan et al. 2016,
ApJ 819, 7). The stellar radius has decreased by 9% in 5 months (cf.
free-fall timescale t_ff~0.6 yr), suggesting that it is undergoing
significant structural changes due to a switchover from He- to
C-burning. This presents an unprecedented opportunity to observe the
process and detect the presence of high-energy processes should they
exist. Any detection of X-rays will be of fundamental importance to
understand the phenomenon being exhibited by Betelgeuse. If
undetected, we will set stringent upper limits to the X-ray flux by
combining these data with prior Chandra Cal observations.

Sequence Number: 201343

Title : The Dimming of Betelgeuse
PI: Kashyap
Abstract: Betelgeuse (M2Iab) is a prime candidate for an impending supernova. It
has been exhibiting an unprecedented dimming (Guinan & Wasatonic, ATEL
13410), dropping in luminosity by ~25% since Sep 2019. Prima facie
this cannot be attributed to adiabatic upwelling of higher temperature
material which explains its usual variability (see Dolan et al. 2016,
ApJ 819, 7). The stellar radius has decreased by 9% in 5 months (cf.
free-fall timescale t_ff~0.6 yr), suggesting that it is undergoing
significant structural changes due to a switchover from He- to
C-burning. This presents an unprecedented opportunity to observe the
process and detect the presence of high-energy processes should they
exist. Any detection of X-rays will be of fundamental importance to
understand the phenomenon being exhibited by Betelgeuse. If
undetected, we will set stringent upper limits to the X-ray flux by
combining these data with prior Chandra Cal observations.

Sequence Number: 503200

Title : The nearby TypeIc/Ic-BL SN2020oi in M100 (d~16 Mpc)
PI: Stroh
Abstract: SN2020oi is a young type Ic/Ic-BL SN in the very nearby galaxy M100
(16 Mpc). We request X-ray follow-up in coordination with follow-up
across the spectrum with the primary objective to constrain the shock
velocity and the density in the nearby environment of the explosion.

Sequence Number: 503199

Title : The nearby TypeIc/Ic-BL SN2020oi in M100 (d~16 Mpc)
PI: Stroh
Abstract: SN2020oi is a young type Ic/Ic-BL SN in the very nearby galaxy M100
(16 Mpc). We request X-ray follow-up in coordination with follow-up
across the spectrum with the primary objective to constrain the shock
velocity and the density in the nearby environment of the explosion.

Sequence Number: 503198

Title : Chandra Observation of SN 2019yvq
PI: Pooley
Abstract: In 15 ksec of merged Swift/XRT observations since Dec 29, there are
26.1 +/- 6.0 net counts (0.2-10 keV) in a 45" aperture centered on the
Type Ia SN 2019yvq in NGC 4441 (19 Mpc). In a previous Swift
observation of the field from 2012, using the same source and
background regions, 7.1 +/- 3.5 net counts are detected. The clear
detection of an X-ray source in the new data may be from the SN or
possibly from an unrelated source. Chandra's sensitivity and spatial
resolution are necessary to determine the origin of the X-rays.

Sequence Number: 704036

Title : Follow-up of a Weak-Line Quasar with Extreme X-ray Variability
PI: Ni
Abstract: We request an observation of SDSS J1539+3954, a weak-line quasar (WLQ)
that exhibited extreme X-ray variability, to monitor its potential
change in X-ray flux. In Sept 2019, we unexpectedly discovered that
the X-ray flux of SDSS J1539+3954 had increased by a factor of > 20.
Before this rise, it appeared X-ray weak compared with the expectation
from its UV flux; after the rise, the ratio of its X-ray flux and UV
flux is consistent with the majority of the AGN population. In the
context of the thick inner accretion-disk model we proposed for WLQs,
the extreme X-ray variability could arise due to a slight change in
the thickness of the disk that moved across our line of sight. When
our line of sight intercepts the disk, we observe an X-ray weak state;
when it misses the disk, we observe an X-ray normal state. Monitoring
the potential X-ray state transition before the next Chandra CfP will
greatly help to constrain the timescale of such transitions, thus
probing the accretion-disk physics.

Sequence Number: 402196

Title : Intrabinary shock emission of the black widow candidate 4FGL
J0336.0+7502
PI: Li
Abstract: Many millisecond pulsars are in binary and some special ones are in
compact orbits, whose the periods are less than 1d. Depending on the
companion type, these MSPs are named black widow or redback. The
binary members in a black widow/redback are just separated by a few
solar radii. Under this extreme condition, pulsar intrabinary shock
(IBS), where the stellar/pulsar winds severely collides, is formed.
One side of the tidally-locked companion is heated by IBS that results
in orbital modulation in optical. The X-ray emission will also be
modulated by Doppler boosting. 4FGL J0336.0+7502 is a strong black
widow candidate, which was recently identified by our MSP hunting
campaign. Not only showing gamma-ray properties comparable to other
black widows, an optical counterpart that exhibits 3.72-h modulation
was also found. An X-ray counterpart is detected by Swift/XRT in 2012,
but just marginally. We propose a 15ks (~1 orbit) Chandra observation
to confirm the detection and study the IBS.

Sequence Number: 300467

Title : UNEXPECTED EARLY PERIASTRON PASSAGE AND ECLIPSE IN THE SYMBIOTIC
SYSTEM R AQR
PI: Karovska
Abstract: We propose a 50ks ACIS-S DDT observation of the interacting symbiotic
binary (where a WD accretes from the powerful wind of an evolved
giant), RAqr. The white dwarf accretor is making an unexpected early
approach to the mass donor Mira star. The enhanced activity in the
system has resulted in a powerful outburst and mass ejection, leading
to dust formation eclipsing the donor star, as evidenced by the recent
dramatic dimming of the optical light of RAqr. Symbiotic systems are
of great importance because they are likely progenitors of a fraction
of asymmetric Planetary Nebulae (PN), and of cosmological distance
indicator SN Ia. Understanding the characteristics of the accretion
onto the WD, and of the surrounding environment, especially during
powerful mass-loss events and outbursts around periastron, are crucial
steps to determine the precursor conditions for formation of PN and SN
Ia. ToO observing time has been granted recently on JVLA , HST, and
Swift to study this rare event.

Sequence Number: 704032

Title : X-ray jet at very high redshift
PI: moretti
Abstract: Powerful radio-loud QSOs emit relativistic jets of plasma. At high
redshift, their X-ray emission is thought to be partially due to the
interaction of the plasma with the CMB photons. Since CMB photon
density strongly evolves with redshift, radio-loud QSO X-ray
luminosity is expected to quickly increase in the early Universe. We
propose to observe PSO0309+47, the most luminous X-ray and radio QSO
recently discovered at z>6.0. Its redshift (z=6.1) and the QSO nature
has been confirmed by optical LBT spectrum in October 2019. A short
Swift-XRT observation, in November 2019, allowed us to roughly
estimate its X-ray spectral properties. Interestingly, the position of
the X-ray counterpart is (marginally) inconsistent with the optical
one. This could be interpreted as the signature of a jet interacting
with the CMB photons. A Chandra 25Ks observation, with 50 source
photons expected, would be able to confirm the positional offset and
to assess the extension of the source.

Sequence Number: 402195

Title : An accurate position of a new ULX in NGC 4045
PI: Brightman
Abstract: We recently detected a new X-ray source with Swift/XRT that appears to
be associated with the galaxy NGC 4045 (D=32 Mpc). The source was
first detected by Swift on 2019-12-04 and the latest detection was on
2019-12-06 with a count rate of 1.4E-02+/-3.3E-03 ct/s. The spectrum
can be described by a powerlaw with Gamma=1.1+/-0.7. The 0.3--10 keV
flux is 6.8E-13 ergs/cm2/s, which at a distance of 32 Mpc corresponds
to a luminosity of 6.3E+40 erg/s. The source is likely a new ULX. No
previous X-ray source has been catalogued within several armin of this
source. Observations with Swift several months prior yielded only
upper limits below the current count rate. We request a 10-ks Chandra
observation in order to obtain an accurate position that will
potentially enable the identification of an optical/NIR counterpart.
An OIR counterpart could yield information about the donor star of the
ULX. The 90% positional uncertainty from Swift is only 5.1" and would
yield several counterpart candidates.

Sequence Number: 100192

Title : Chandra Observations of the Interstellar Comet C/2019 Q4 Borisov
PI: Snios
Abstract: Comet 2019/Q4 Borisov is only the second-known interstellar object
detected within the Solar System, and the first to be discovered prior
to reaching its perihelion. This presents a unique opportunity to
extensively observe this exotic comet during its closest approach to
Earth prior to its exit from the Solar System. X-ray observations of
C/2019 Q4 may be used to measure dust and gas outflow rates from the
source, neutral particle interactions with Solar Wind, and variations
in outflow rates and morphology. These properties may also be compared
against Solar System comets/asteroids to probe for differences, if
any, with the exosolar object. We therefore propose to observe C/2019
Q4 with Chandra HRC during its perihelion on 27-Dec-2019 to quantify
the afore-mentioned physical properties of this interstellar comet.

Sequence Number: 100192

Title : Chandra Observations of the Interstellar Comet C/2019 Q4 Borisov
PI: Snios
Abstract: Comet 2019/Q4 Borisov is only the second-known interstellar object
detected within the Solar System, and the first to be discovered prior
to reaching its perihelion. This presents a unique opportunity to
extensively observe this exotic comet during its closest approach to
Earth prior to its exit from the Solar System. X-ray observations of
C/2019 Q4 may be used to measure dust and gas outflow rates from the
source, neutral particle interactions with Solar Wind, and variations
in outflow rates and morphology. These properties may also be compared
against Solar System comets/asteroids to probe for differences, if
any, with the exosolar object. We therefore propose to observe C/2019
Q4 with Chandra HRC during its perihelion on 27-Dec-2019 to quantify
the afore-mentioned physical properties of this interstellar comet.

Sequence Number: 100192

Title : Chandra Observations of the Interstellar Comet C/2019 Q4 Borisov
PI: Snios
Abstract: Comet 2019/Q4 Borisov is only the second-known interstellar object
detected within the Solar System, and the first to be discovered prior
to reaching its perihelion. This presents a unique opportunity to
extensively observe this exotic comet during its closest approach to
Earth prior to its exit from the Solar System. X-ray observations of
C/2019 Q4 may be used to measure dust and gas outflow rates from the
source, neutral particle interactions with Solar Wind, and variations
in outflow rates and morphology. These properties may also be compared
against Solar System comets/asteroids to probe for differences, if
any, with the exosolar object. We therefore propose to observe C/2019
Q4 with Chandra HRC during its perihelion on 27-Dec-2019 to quantify
the afore-mentioned physical properties of this interstellar comet.

Sequence Number: 100192

Title : Chandra Observations of the Interstellar Comet C/2019 Q4 Borisov
PI: Snios
Abstract: Comet 2019/Q4 Borisov is only the second-known interstellar object
detected within the Solar System, and the first to be discovered prior
to reaching its perihelion. This presents a unique opportunity to
extensively observe this exotic comet during its closest approach to
Earth prior to its exit from the Solar System. X-ray observations of
C/2019 Q4 may be used to measure dust and gas outflow rates from the
source, neutral particle interactions with Solar Wind, and variations
in outflow rates and morphology. These properties may also be compared
against Solar System comets/asteroids to probe for differences, if
any, with the exosolar object. We therefore propose to observe C/2019
Q4 with Chandra HRC during its perihelion on 27-Dec-2019 to quantify
the afore-mentioned physical properties of this interstellar comet.

Sequence Number: 100192

Title : Chandra Observations of the Interstellar Comet C/2019 Q4 Borisov
PI: Snios
Abstract: Comet 2019/Q4 Borisov is only the second-known interstellar object
detected within the Solar System, and the first to be discovered prior
to reaching its perihelion. This presents a unique opportunity to
extensively observe this exotic comet during its closest approach to
Earth prior to its exit from the Solar System. X-ray observations of
C/2019 Q4 may be used to measure dust and gas outflow rates from the
source, neutral particle interactions with Solar Wind, and variations
in outflow rates and morphology. These properties may also be compared
against Solar System comets/asteroids to probe for differences, if
any, with the exosolar object. We therefore propose to observe C/2019
Q4 with Chandra HRC during its perihelion on 27-Dec-2019 to quantify
the afore-mentioned physical properties of this interstellar comet.

Sequence Number: 503197

Title : Simultaneous X-ray and Radio Observations of the Second Localized
Repeating Fast Radio Burst
PI: Scholz
Abstract: We have localized the CHIME/FRB-discovered repeating FRB
180916.J0158+65 to milliarcsecond precision using the European VLBI
Network and identified its host and redshift using Gemini North
observations. This is the second sub-arcsecond localization of a
repeating FRB. The redshift of the host galaxy implies a luminosity
distance at least six times closer than the only other localized
repeater, FRB 121102. Therefore, FRB 180916 can be used to probe much
deeper for X-ray emission from repeating FRBs. We propose to perform
simultaneous observations using Chandra and the 100-m Effelsberg radio
telescope to probe for X-ray emission at the times of radio bursts
from FRB 180916. See attached 1 page science justification for more
information.

Sequence Number: 503197

Title : Simultaneous X-ray and Radio Observations of the Second Localized
Repeating Fast Radio Burst
PI: Scholz
Abstract: We have localized the CHIME/FRB-discovered repeating FRB
180916.J0158+65 to milliarcsecond precision using the European VLBI
Network and identified its host and redshift using Gemini North
observations. This is the second sub-arcsecond localization of a
repeating FRB. The redshift of the host galaxy implies a luminosity
distance at least six times closer than the only other localized
repeater, FRB 121102. Therefore, FRB 180916 can be used to probe much
deeper for X-ray emission from repeating FRBs. We propose to perform
simultaneous observations using Chandra and the 100-m Effelsberg radio
telescope to probe for X-ray emission at the times of radio bursts
from FRB 180916. See attached 1 page science justification for more
information.

Sequence Number: 100192

Title : Chandra Observations of the Interstellar Comet C/2019 Q4 Borisov
PI: Snios
Abstract: Comet 2019/Q4 Borisov is only the second-known interstellar object
detected within the Solar System, and the first to be discovered prior
to reaching its perihelion. This presents a unique opportunity to
extensively observe this exotic comet during its closest approach to
Earth prior to its exit from the Solar System. X-ray observations of
C/2019 Q4 may be used to measure dust and gas outflow rates from the
source, neutral particle interactions with Solar Wind, and variations
in outflow rates and morphology. These properties may also be compared
against Solar System comets/asteroids to probe for differences, if
any, with the exosolar object. We therefore propose to observe C/2019
Q4 with Chandra HRC during its perihelion on 27-Dec-2019 to quantify
the afore-mentioned physical properties of this interstellar comet.

Sequence Number: 704028

Title : Gravitational millilensing as a tool for studying the
microarcsec-scale structure in PKS1413+135
PI: Liodakis
Abstract: We have recently identified a new type of symmetric achromatic
variability (SAV) in light curves of AGN, which we suggest is due to
gravitational lensing. This allows us to probe lenses in the mass
range of 1e3-1e6 solar masses, which have been challenging to detect.
We propose observations of PKS1413+135, which has previously shown 5
SAVs in its radio light curve over the past 27 yrs and now shows
indications that a new event has recently started. Based on previous
events we expect it to continue until 07/2020. This is the first event
ever to be identified while in progress. We expect the X-rays to
follow the same achromatic trend seen in radio, observations of which
are underway. We request 17-4ks-pointings separated by 2 weeks that
will allow us to monitor the X-ray flux evolution during the event and
confirm its achromatic nature. Depending on the outcome, we will have
the unique opportunity to study grav. millilensing, plasma lensing or
intrinsic variability in relativistic jets.

Sequence Number: 704028

Title : Gravitational millilensing as a tool for studying the
microarcsec-scale structure in PKS1413+135
PI: Liodakis
Abstract: We have recently identified a new type of symmetric achromatic
variability (SAV) in light curves of AGN, which we suggest is due to
gravitational lensing. This allows us to probe lenses in the mass
range of 1e3-1e6 solar masses, which have been challenging to detect.
We propose observations of PKS1413+135, which has previously shown 5
SAVs in its radio light curve over the past 27 yrs and now shows
indications that a new event has recently started. Based on previous
events we expect it to continue until 07/2020. This is the first event
ever to be identified while in progress. We expect the X-rays to
follow the same achromatic trend seen in radio, observations of which
are underway. We request 17-4ks-pointings separated by 2 weeks that
will allow us to monitor the X-ray flux evolution during the event and
confirm its achromatic nature. Depending on the outcome, we will have
the unique opportunity to study grav. millilensing, plasma lensing or
intrinsic variability in relativistic jets.

Sequence Number: 704028

Title : Gravitational millilensing as a tool for studying the
microarcsec-scale structure in PKS1413+135
PI: Liodakis
Abstract: We have recently identified a new type of symmetric achromatic
variability (SAV) in light curves of AGN, which we suggest is due to
gravitational lensing. This allows us to probe lenses in the mass
range of 1e3-1e6 solar masses, which have been challenging to detect.
We propose observations of PKS1413+135, which has previously shown 5
SAVs in its radio light curve over the past 27 yrs and now shows
indications that a new event has recently started. Based on previous
events we expect it to continue until 07/2020. This is the first event
ever to be identified while in progress. We expect the X-rays to
follow the same achromatic trend seen in radio, observations of which
are underway. We request 17-4ks-pointings separated by 2 weeks that
will allow us to monitor the X-ray flux evolution during the event and
confirm its achromatic nature. Depending on the outcome, we will have
the unique opportunity to study grav. millilensing, plasma lensing or
intrinsic variability in relativistic jets.

Sequence Number: 704028

Title : Gravitational millilensing as a tool for studying the
microarcsec-scale structure in PKS1413+135
PI: Liodakis
Abstract: We have recently identified a new type of symmetric achromatic
variability (SAV) in light curves of AGN, which we suggest is due to
gravitational lensing. This allows us to probe lenses in the mass
range of 1e3-1e6 solar masses, which have been challenging to detect.
We propose observations of PKS1413+135, which has previously shown 5
SAVs in its radio light curve over the past 27 yrs and now shows
indications that a new event has recently started. Based on previous
events we expect it to continue until 07/2020. This is the first event
ever to be identified while in progress. We expect the X-rays to
follow the same achromatic trend seen in radio, observations of which
are underway. We request 17-4ks-pointings separated by 2 weeks that
will allow us to monitor the X-ray flux evolution during the event and
confirm its achromatic nature. Depending on the outcome, we will have
the unique opportunity to study grav. millilensing, plasma lensing or
intrinsic variability in relativistic jets.

Sequence Number: 704028

Title : Gravitational millilensing as a tool for studying the
microarcsec-scale structure in PKS1413+135
PI: Liodakis
Abstract: We have recently identified a new type of symmetric achromatic
variability (SAV) in light curves of AGN, which we suggest is due to
gravitational lensing. This allows us to probe lenses in the mass
range of 1e3-1e6 solar masses, which have been challenging to detect.
We propose observations of PKS1413+135, which has previously shown 5
SAVs in its radio light curve over the past 27 yrs and now shows
indications that a new event has recently started. Based on previous
events we expect it to continue until 07/2020. This is the first event
ever to be identified while in progress. We expect the X-rays to
follow the same achromatic trend seen in radio, observations of which
are underway. We request 17-4ks-pointings separated by 2 weeks that
will allow us to monitor the X-ray flux evolution during the event and
confirm its achromatic nature. Depending on the outcome, we will have
the unique opportunity to study grav. millilensing, plasma lensing or
intrinsic variability in relativistic jets.

Sequence Number: 100191

Title : Exoplanet evaporation in the only known young 4-planet system
PI: Poppenhaeger
Abstract: Exoplanets lose their atmospheres through evaporation driven by
stellar X-ray emission. This leads to a gap observed in exoplanetary
radii; but the physics of evaporation is not well understood. A few
days ago, a new exoplanet system was discovered with 4 low-density and
hence easily evaporable exoplanets and a very young (25 Myr) host star
called V1298 Tau. This is the age at which the bulk of evaporation
should happen, and we can extract key insights on the evaporation
strength from this system if the X-ray luminosity of the host star is
known. ROSAT shows there is a source with a count rate of 0.15 cps
near the position of the star (Lx=2e30 erg/s). But there are 2 other
young stars in the ROSAT PSF (the smallest separation being 25
arcsec), so it is unclear if or how much of the flux stems from the
exoplanet host star. We ask for 1 ks of Chandra time with ACIS-S. This
will yield 70 counts in total, and we will easily determine how much
flux stems from the exoplanet host star.

Sequence Number: 402194

Title : GRS 1915+105 as a Changing-Look Microquasar
PI: Miller
Abstract: GRS 1915+105 is currently in a low flux state, with a flux of about 1
E-10 erg/cm^2/s. This is two orders of magnitude lower than the flux
for which it is famous. Via Swift monitoring, we know that the flux is
diminished partly through internal obscuration. At times, the source
now appears to be Compton-thick. GRS 1915+105 has always been a
Rosetta Stone source that has helped us to better understand quasars.
Now, it appears to be a highly obscured Seyfert-2 or Compton-thick
AGN. Swift spectra give us broad ideas about what might be happening,
but our simulations suggest that 30 ks Chandra/HETGS spectra can
reveal far more, including Doppler broadening of the flux that is
reflected by the obscuring material, and highly ionized outflows. It
may be the case that the obscuring material is actually an extreme
outflow, and that the source is losing more mass than it accretes. An
email has been sent to the director with a plot from one simulation.

Sequence Number: 402193

Title : GRS 1915+105 as a Changing-Look Microquasar
PI: Miller
Abstract: GRS 1915+105 is currently in a low flux state, with a flux of about 1
E-10 erg/cm^2/s. This is two orders of magnitude lower than the flux
for which it is famous. Via Swift monitoring, we know that the flux is
diminished partly through internal obscuration. At times, the source
now appears to be Compton-thick. GRS 1915+105 has always been a
Rosetta Stone source that has helped us to better understand quasars.
Now, it appears to be a highly obscured Seyfert-2 or Compton-thick
AGN. Swift spectra give us broad ideas about what might be happening,
but our simulations suggest that 30 ks Chandra/HETGS spectra can
reveal far more, including Doppler broadening of the flux that is
reflected by the obscuring material, and highly ionized outflows. It
may be the case that the obscuring material is actually an extreme
outflow, and that the source is losing more mass than it accretes. An
email has been sent to the director with a plot from one simulation.

Sequence Number: 503196

Title : Chasing high energy emission from neutron star black holes merger
PI: Jaodand
Abstract: GW170817 opened up a new, interesting question in astronomy- what
would a neutron star black hole (NSBH) merger look like. In case of
such merger below a certain mass threshold where the NS is tidally
disrupted beyond an innermost stable circular orbit we expect to see a
bright red kilonova accompanied by a high mass tidal ejecta up to 0.1
M_Sun. Very recently, on August 14, LIGO/Virgo observatories jointly
detected a very promising NS-BH event (LIGO/Virgo S190814bv).
Detection of rising radio counterpart with ASKAP makes it first NS-BH
merger with a multi-wavelength counterpart, suggesting polar ejecta
launch from the system. Understanding the event with complimentary
high energy observations would shed critical light on neutron star
disruption process by a BH and ultimately allow us to understand the
state of matter and NS composition. Swift initially carried out 451
triggered observations of the LVC region with no counterpart. We dont
see a Swift counterpart in todays observation.

Sequence Number: 300466

Title : The recurrent nova outburst of V3890 Sgr
PI: Orio
Abstract: The symbiotic recurrent nova (RN) V3890 Sgr is having its third known
outburst. Symbiotic RN are strong X-ray sources since the first days.
The Chandra HETG spectrum of RS Oph on day 13 showed strong emission
lines of a multi-temperature plasma, due to the red giant wind
shock-heated by the new, "violent" outflow (Nelson et al. 2008, ApJ
637, 1067; Ness et al. 2009, ApJ 137, 3414). The derived plasma
temperature and the emission line profile are used to constrain the
mass of the ejecta and the outflow geometry, as done by Drake et al.
(2015, ApJ 825, 95) and Orlando et al. (2017, MNRAS 464, 5003) for the
outburst of V745 Sco. In RS Oph and V745 Sco, both hosting massive
white dwarfs, the ejected mass was lower than the accreted envelope,
yielding credibility to symbiotic recurrent novae as a channel to
supernovae Ia explosions. The present outburst of V3890 Sgr will give
important terms of comparison for the outflow models and the possible
path to SN Ia.

Sequence Number: 300465

Title : Catching the return to quiescence of a classical nova post-explosion
system: the unique opportunity for V1369 Cen
PI: Drake
Abstract: The central role of a thermonuclear runaway and explosive envelope
ejection in classical novae (CN) is well established but how, and if,
the system relaxes back to its pre-CN state is unknown. The immediate
aftermath, when accretion restarts and a disk reappears, is crucial
for the initial conditions for any subsequent explosion and the
presumed path toward the cataclysmic variable stage. Understanding
this vital phase requires observing fresh post-CN systems, where
X-rays are essential for diagnosing renewed accretion. This is
extremely difficult because CN are usually distant, obscured and very
faint. CN V1369 Cen 2013 is the best chance to make these
observations. Recent optical-NIR VLT spectra indicate a disk-like
structure is reforming, while Swift data show possible evidence of
renewed accretion. However, Swift could be seeing CN ejecta and
spectral quality is too poor to diagnose the source nature. Chandra
can make the crucial observations to understand the state of the
source.

Sequence Number: 402123

Title : Imaging of Swift J1728.9-3613
PI: Miller
Abstract: The SJ has been sent in an email to the Director.

Sequence Number: 402122

Title : Propeller effect in 4U1901+03 - measuring the spectrum after the
transition
PI: Lutovinov
Abstract: We are asking to observe the transient HMXB 4U1901+03, that recently
went into an outburst. XRT observations showed a dramatic decrease in
the source flux - 30 times in 3 days. This sudden dimming is
reminiscent of an onset of the propeller effect similar to other
well-known HMXBs. The source is currently in a low-luminosity state
with the flux of 5e-13 erg/cm2/s (0.5-10 keV). Because of this low
flux we are asking Chandra observations in order to measure the
spectrum of 4U1901+03, a few days after the transition to the
propeller regime to finally confirm it and to determine the spectral
parameters. It also should be noted that there are no a visibility of
this source with XMM-Newton, so only Chandra can help in the solving
the problem. We are asking for the 10 ks observation. Using PIMMS we
estimated that it will be enough to measure accurately the spectral
shape and to understand is it blackbody-like or are there any
deviations from it.

Sequence Number: 402121

Title : HETG Study of Emission & Absorption Lines in X-ray Bursts from 4U
1820-30
PI: Heinke
Abstract: Strohmayer+2019 saw an emission line (1.04 keV) and two absorption
lines (1.7, 3.0 keV) during the peak of NICER PRE bursts from 4U
1820-30. The lines occur reproducibly in multiple bursts, and are
clearly present in each of the 4 brightest bursts. The energies are
4.6% bluer in brighter than fainter bursts; gravitational or
wind-induced shift? NICER cannot resolve the lines (<70 eV). 4U
1820-30 often (but not always) undergoes low/hard states at six-month
intervals, and strong PRE bursts. NICER has seen bursts every 7 ks in
the last 10 days. The burst lines appear in the PRE phase, ~0.7
seconds each. Simulating these lines (HETG MEG), a single burst is
insufficient; we estimate five PRE bursts will give a >3 sigma
measurement of the 1.7 keV absorption line and 1.04 keV emission line
(the 3 keV absorption feature would likely be only marginally
detected). For a burst every 10 ks, 50 ks should give 5 bursts,
allowing clear HETG detections and measurements.

Sequence Number: 402121

Title : HETG Study of Emission & Absorption Lines in X-ray Bursts from 4U
1820-30
PI: Heinke
Abstract: Strohmayer+2019 saw an emission line (1.04 keV) and two absorption
lines (1.7, 3.0 keV) during the peak of NICER PRE bursts from 4U
1820-30. The lines occur reproducibly in multiple bursts, and are
clearly present in each of the 4 brightest bursts. The energies are
4.6% bluer in brighter than fainter bursts; gravitational or
wind-induced shift? NICER cannot resolve the lines (<70 eV). 4U
1820-30 often (but not always) undergoes low/hard states at six-month
intervals, and strong PRE bursts. NICER has seen bursts every 7 ks in
the last 10 days. The burst lines appear in the PRE phase, ~0.7
seconds each. Simulating these lines (HETG MEG), a single burst is
insufficient; we estimate five PRE bursts will give a >3 sigma
measurement of the 1.7 keV absorption line and 1.04 keV emission line
(the 3 keV absorption feature would likely be only marginally
detected). For a burst every 10 ks, 50 ks should give 5 bursts,
allowing clear HETG detections and measurements.

Sequence Number: 503149

Title : The Extended Circumstellar Environment of SN 2003gk
PI: Patnaude
Abstract: The mass loss history of massive stars is one of the least understood
yet fundamental aspects of massive stars. Supernovae shocks, evolving
on timescales of years, allow us to probe 100s to 1000s of years of
stellar evolution, including the crucial time leading up to core
collapse. The X-ray emission from this interaction informs us on the
density and extent of the circumstellar environment, and can provide
clues as to how and when massive stars lose their envelopes, and if
the timing is related to the subsequent core collapse. Observations of
some stripped envelope SNe indicate that the CSM interaction is
delayed, suggesting that the mass loss event occurs on timescales <
10,000 yrs before core collapse. This is in contrast to other Type II
SNe, which can show immediate, strong interaction (IIn) or weak,
extended CSM interaction (IIP/L), suggesting that they type of CSM
interaction is related to the SNe subtype, and may point to a
relationship between progenitor and SN type.

Sequence Number: 703897

Title : Chandra observation of the gravitationally lensed balzar PKS 1830-211
during its brightest outburst
PI: Buson
Abstract: PKS 1830-211 is a gravitationally lensed blazar at z~2.5 with two
images at ~1" separation which are well resolved in the two earlier
Chandra HETGS images. The blazar is currently undergoing strong
flaring activity at gamma rays. Chandra has carried out observations
during this enhanced state, and demonstrated the effectiveness of
resolving the emission from two images and providing crucial insights.
We propose an additional timely observation, taking advantage of the
newly acquired dataset and upcoming visit.

Sequence Number: 703896

Title : Chandra observation of the gravitationally lensed balzar PKS 1830-211
during its brightest outburst
PI: Buson
Abstract: PKS 1830-211 is a gravitationally lensed blazar at z~2.5 with two
images at ~1" separation which are well resolved in the two earlier
Chandra HETGS images. The blazar is currently undergoing strong
flaring activity at gamma rays. Chandra has carried out observations
during this enhanced state, and demonstrated the effectiveness of
resolving the emission from two images and providing crucial insights.
We propose an additional timely observation, taking advantage of the
newly acquired dataset and upcoming visit.

Sequence Number: 402117

Title : The Microquasar GRS 1915+105 in an Unprecedented Quiet State
PI: Miller
Abstract: Right now, GRS 1915+105 is in an unprecedented state: it is 20-50
times fainter in X-rays than typically measured. The source has never
been this faint, and nor for such a long period, in the entire history
of RXTE, Swift, and MAXI monitoring. This state has persisted for
several weeks, but there is no indication for how long it may last. A
Swift XRT snapshot on 4/23 confirms that the source now has a flux of
just 50 mCrab, or about 1 E-9 erg/cm2/s, in the 1-10 keV band. In a
normal state, GRS 1915+105 is observed at 500-2000 mCrab. This
spectrum is itself quite odd, consistent with a very hot blackbody (kT
= 2.4 keV). The most recent MAXI data suggest the flux is a factor of
~2 lower on 4/24. GRS 1915+105 can be observed with the HETGS without
CC mode, and without blocking the zeroth order. This will permit a
spectrum of an unprecedented state in a critical source, and an
examination of the local jet-impacted environment through imaging.

Sequence Number: 703892

Title : The X-ray obscured quasar J085051: Dust free gas or an eclipse?
PI: Civano
Abstract: Typically, luminous broad line quasar show no or minimal obscuration
in the X-ray band. A small percentage (3%) of X-ray survey selected
sources present broad optical emission lines and mild X-ray
obscuration, supposedly due to dust-free gas not obscuring the broad
line regions. However, given the non simultaneity of the data, a
simple explanation could be that these sources are transitioning from
obscured to unobscured due to e.g. transiting obscuring clouds. The
SDSS broad line quasar J085051 (z=0.66) was recently selected as CCT.
While a bright unobscured spectrum was expected, we observed 60 counts
(0.5-8 keV) and high obscuration (NH=7x10^22pm2.5). We obtained 2 new
optical spectra with the FAST and MDM spectrographs (within 15 and 30
days respectively from the X-ray obsid). Very interestingly we measure
a change in the spectral slope, with the source getting bluer
(difference between the new FAST/MDM spectra and SDSS is m~0.75 at
4300A), confirmed also by new g and r photometry.

Sequence Number: 703887

Title : Chandra observation of the gravitationally lensed balzar PKS 1830-211
during its brightest outburst
PI: Buson
Abstract: PKS 1830-211 is a gravitationally lensed blazar at z~2.5 with two
images at ~1" separation which are well resolved in the two earlier
Chandra HETGS images. Previous observations show strong NH variations
due to variable obscuration in the source. PKS1830 is currently
undergoing its brightest and longest outburst at gamma-rays and
X-rays. INTEGRAL-IBIS gives a 20-50 keV flux of around 6e-11cgs, ~10x
brighter than during the archival Chandra observations. There is short
term variability. We are monitoring the flare with XRT and Fermi, but
these do not resolve the lensed source images. Macro-lensing and
micro-lensing has been detected in this system. The measurement of the
magnification ratio is of special interest given the contradictory
values found with radio and gamma observations. The 3 Chandra
observations of ~20ks each, which should provide spectra that are much
higher SNR than the archival observation, will allow us to determine
NH and the spectral index for both images.

Sequence Number: 703886

Title : Chandra observation of the gravitationally lensed balzar PKS 1830-211
during its brightest outburst
PI: Buson
Abstract: PKS 1830-211 is a gravitationally lensed blazar at z~2.5 with two
images at ~1" separation which are well resolved in the two earlier
Chandra HETGS images. Previous observations show strong NH variations
due to variable obscuration in the source. PKS1830 is currently
undergoing its brightest and longest outburst at gamma-rays and
X-rays. INTEGRAL-IBIS gives a 20-50 keV flux of around 6e-11cgs, ~10x
brighter than during the archival Chandra observations. There is short
term variability. We are monitoring the flare with XRT and Fermi, but
these do not resolve the lensed source images. Macro-lensing and
micro-lensing has been detected in this system. The measurement of the
magnification ratio is of special interest given the contradictory
values found with radio and gamma observations. The 3 Chandra
observations of ~20ks each, which should provide spectra that are much
higher SNR than the archival observation, will allow us to determine
NH and the spectral index for both images.

Sequence Number: 703885

Title : Chandra observation of the gravitationally lensed balzar PKS 1830-211
during its brightest outburst
PI: Buson
Abstract: PKS 1830-211 is a gravitationally lensed blazar at z~2.5 with two
images at ~1" separation which are well resolved in the two earlier
Chandra HETGS images. Previous observations show strong NH variations
due to variable obscuration in the source. PKS1830 is currently
undergoing its brightest and longest outburst at gamma-rays and
X-rays. INTEGRAL-IBIS gives a 20-50 keV flux of around 6e-11cgs, ~10x
brighter than during the archival Chandra observations. There is short
term variability. We are monitoring the flare with XRT and Fermi, but
these do not resolve the lensed source images. Macro-lensing and
micro-lensing has been detected in this system. The measurement of the
magnification ratio is of special interest given the contradictory
values found with radio and gamma observations. The 3 Chandra
observations of ~20ks each, which should provide spectra that are much
higher SNR than the archival observation, will allow us to determine
NH and the spectral index for both images.

Sequence Number: 201266

Title : The Origin and Impact of Flares in the Proxima Centauri Planetary
System
PI: MacGregor
Abstract: M dwarfs are the most abundant stars in the galaxy and have a high
frequency of Earth-size planets, making them favored targets of
missions to detect/characterize exoplanets. However, these stars
exhibit high levels of activity, raising questions about the
habitability of their planets. We recently detected a large flare from
Proxima Cen with ALMA (MacGregor et al. 2018) that raises questions
about the relationship between particle acceleration and plasma
heating during flares. To explore this further, we are conducting a
multi-wavelength monitoring campaign of Proxima Cen involving ground-
and space-based facilities. Measuring X-ray flaring energies is
critical, since high energy radiation can erode a planet's atmosphere
by photodissociating water and ozone. We propose to obtain
simultaneous coverage with Chandra to constrain the X-ray properties
of detected flares and their impact on planetary habitability, and to
determine how flaring emission correlates across the EM spectrum.

Sequence Number: 201265

Title : The Origin and Impact of Flares in the Proxima Centauri Planetary
System
PI: MacGregor
Abstract: M dwarfs are the most abundant stars in the galaxy and have a high
frequency of Earth-size planets, making them favored targets of
missions to detect/characterize exoplanets. However, these stars
exhibit high levels of activity, raising questions about the
habitability of their planets. We recently detected a large flare from
Proxima Cen with ALMA (MacGregor et al. 2018) that raises questions
about the relationship between particle acceleration and plasma
heating during flares. To explore this further, we are conducting a
multi-wavelength monitoring campaign of Proxima Cen involving ground-
and space-based facilities. Measuring X-ray flaring energies is
critical, since high energy radiation can erode a planet's atmosphere
by photodissociating water and ozone. We propose to obtain
simultaneous coverage with Chandra to constrain the X-ray properties
of detected flares and their impact on planetary habitability, and to
determine how flaring emission correlates across the EM spectrum.

Sequence Number: 703879

Title : Exploring the possible link between mass ejection and X-ray emission
in a nearby TDE
PI: Alexander
Abstract: AT2019ahk is a rare nearby (110 Mpc) candidate tidal disruption event
(TDE) discovered on 29 January 2019. This source was detected
unusually early (1 month before peak optical light), allowing for
excellent constraints on the properties of the disrupting SMBH and
detailed followup with Swift and ground-based facilities. Our ALMA
observations of this event reveal the first detection of mm emission
from an optical TDE, a signpost of mass ejection. XRT reveals the
event to be X-ray faint, with implications for a proposed radio/X-ray
correlation in radio TDEs. Here, we propose Chandra observations to 1)
determine the temporal behavior of the X-ray source and establish a
link to the UV/optical and mm evolution; 2) use Chandra's superior
angular resolution to pinpoint its location and determine whether it
is point-like (as expected for a TDE) or extended. AT2019ahk provides
a unique opportunity to test models of SMBH accretion and to study the
entire lifecycle of a weak SMBH jet.

Sequence Number: 703878

Title : Exploring the possible link between mass ejection and X-ray emission
in a nearby TDE
PI: Alexander
Abstract: AT2019ahk is a rare nearby (110 Mpc) candidate tidal disruption event
(TDE) discovered on 29 January 2019. This source was detected
unusually early (1 month before peak optical light), allowing for
excellent constraints on the properties of the disrupting SMBH and
detailed followup with Swift and ground-based facilities. Our ALMA
observations of this event reveal the first detection of mm emission
from an optical TDE, a signpost of mass ejection. XRT reveals the
event to be X-ray faint, with implications for a proposed radio/X-ray
correlation in radio TDEs. Here, we propose Chandra observations to 1)
determine the temporal behavior of the X-ray source and establish a
link to the UV/optical and mm evolution; 2) use Chandra's superior
angular resolution to pinpoint its location and determine whether it
is point-like (as expected for a TDE) or extended. AT2019ahk provides
a unique opportunity to test models of SMBH accretion and to study the
entire lifecycle of a weak SMBH jet.

Sequence Number: 100182

Title : Chandra-HRC Support for Juno-UVS on Attitude Adjustment Perijoves
PI: Gladstone
Abstract: To study the morphology and physics of Jupiter's auroral x-rays,
through comparison with simultaneous Juno-UVS remote sensing and
Juno-JADE and Juno-JEDI in-situ particle observations. The best Juno
data for Jupiter's northern aurora are now obtained during specific
"attitude adjustments" perijoves, which are only scheduled a few
months ahead of time. Jovian auroral x-rays are associated with a
region of UV emission known as the active region, which likely
coincides with the return current connected with the main auroral
oval. Juno-JEDI provides useful measurements of O ion precipitation,
but only along the magnetic footprint of Juno. Simultaneous maps from
Chandra provide highly scientifically useful supporting observations
for Juno.

Sequence Number: 402115

Title : Determining the X-ray Position of 4U 1901+03
PI: Hemphill
Abstract: Transient X-ray pulsars are excellent laboratories for studying
accretion and binary evolution, due to the large luminosity changes
during an outburst. However, these outbursts are typically infrequent
and aperiodic, often with years or decades between events. For this
reason, many systems are relatively poorly studied. One vital
measurement is the localization of the X-ray source, as this enables
the identification and classification of the optical counterpart, the
donor star, the properties of which are of supreme importance for
understanding the evolution of the system and interpreting the X-ray
spectra and variability of the source. 4U 1901+03 has just begun its
fourth outburst in history, but currently the best position is the
RXTE/PCA 1' error circle, so the optical counterpart is still
unknown.

Sequence Number: 703863

Title : Extraordinary 9 hours quasi-periodic X-ray outbursts from an accreting
SMBH
PI: Miniutti
Abstract: We have observed the Seyfert galaxy GSN 069 on 2018-12-24 with XMM and
discovered two extraordinary X-ray flares spaced by ~30ks. No flares
were detected back in 2014 during a 80 ks XMM observation. We obtained
a further long XMM DDT on 2019-01-17, and obtained 5 extraordinary
quasi-periodic flares separated by ~32ks. This beaviour is unlike
anything seen before in AGN and potentially represent a Rosetta-stone
for our understanding of SMBH accretion and/or dynamics. GSN 069 is
either a re-activated AGN after a long period of quiescence or
(perhaps more likely) a long-lived Tidal Disruption Event.
Interpretations for the extraordinary observed behaviour include GR
precession of the innermost flow, a very close separation SMBH binary
system etc. We need to use the Chandra current visibility window (no
XMM observation is possible now) to follow-up this extraordinary
system and start to constrain the interpretation. More details in the
uploaded PDF science case.

Sequence Number: 402114

Title : Revealing the SXP 4.78 transition in to the 'propeller mode'
PI: Lutovinov
Abstract: One of the most straightforward manifestations of the interaction of
matter with the magnetosphere of a neutron star is a transition of the
accreting neutron star to the so-called propeller regime (Illarionov &
Sunyaev 1975), when the accreting matter is stopped by the centrifugal
barrier set up by the rotating magnetosphere. Such a transition is
expected to occur at the limiting luminosity defined by the dipolar
magnetic field strength and rotation rate of the pulsar. Confident
detection of such a transition provides a completely independent
estimate of the magnetic field of the pulsar and in general allows for
a better understanding of the interaction of the accretion flow and
magnetosphere (Tsygankov et. al. 2016). Measured limiting luminosity,
confirmed with the low flux and changed spectrum in SXP 4.78 will be
utilized to determine magnetic field strength, yet unknown for this
system.

Sequence Number: 703841

Title : Timely Assessment of the X-ray Flux of Newly Discovered Quadruply
Lensed Quasars
PI: Pooley
Abstract: Our previous work has shown the unique power of Chandra observations
of quadruply gravitationally lensed quasars to address several
fundamental astrophysical issues. We have used these observations to
(1) determine the cause of flux ratio anomalies, (2) measure the sizes
of quasar accretion disks, (3) determine the dark matter content of
the lensing galaxies, and (4) measure the stellar mass-to-light ratio
(in fact, this is the only way to measure the stellar mass-to-light
ratio beyond the solar neighborhood). In all cases, the main source of
uncertainty in our results is the small size of the sample of known
quads; only about 15 systems had been available for study with Chandra
unti the past year or two. New, large-area sky surveys have produced a
trove of new quads, and timely Chandra observations will allow for
great progress. We aim to propose such observations in the coming
cycle and seek to assess the unknown X-ray flux now in order to
propose the most efficient GO program.

Sequence Number: 703840

Title : Timely Assessment of the X-ray Flux of Newly Discovered Quadruply
Lensed Quasars
PI: Pooley
Abstract: Our previous work has shown the unique power of Chandra observations
of quadruply gravitationally lensed quasars to address several
fundamental astrophysical issues. We have used these observations to
(1) determine the cause of flux ratio anomalies, (2) measure the sizes
of quasar accretion disks, (3) determine the dark matter content of
the lensing galaxies, and (4) measure the stellar mass-to-light ratio
(in fact, this is the only way to measure the stellar mass-to-light
ratio beyond the solar neighborhood). In all cases, the main source of
uncertainty in our results is the small size of the sample of known
quads; only about 15 systems had been available for study with Chandra
unti the past year or two. New, large-area sky surveys have produced a
trove of new quads, and timely Chandra observations will allow for
great progress. We aim to propose such observations in the coming
cycle and seek to assess the unknown X-ray flux now in order to
propose the most efficient GO program.

Sequence Number: 703839

Title : Timely Assessment of the X-ray Flux of Newly Discovered Quadruply
Lensed Quasars
PI: Pooley
Abstract: Our previous work has shown the unique power of Chandra observations
of quadruply gravitationally lensed quasars to address several
fundamental astrophysical issues. We have used these observations to
(1) determine the cause of flux ratio anomalies, (2) measure the sizes
of quasar accretion disks, (3) determine the dark matter content of
the lensing galaxies, and (4) measure the stellar mass-to-light ratio
(in fact, this is the only way to measure the stellar mass-to-light
ratio beyond the solar neighborhood). In all cases, the main source of
uncertainty in our results is the small size of the sample of known
quads; only about 15 systems had been available for study with Chandra
unti the past year or two. New, large-area sky surveys have produced a
trove of new quads, and timely Chandra observations will allow for
great progress. We aim to propose such observations in the coming
cycle and seek to assess the unknown X-ray flux now in order to
propose the most efficient GO program.

Sequence Number: 703838

Title : Timely Assessment of the X-ray Flux of Newly Discovered Quadruply
Lensed Quasars
PI: Pooley
Abstract: Our previous work has shown the unique power of Chandra observations
of quadruply gravitationally lensed quasars to address several
fundamental astrophysical issues. We have used these observations to
(1) determine the cause of flux ratio anomalies, (2) measure the sizes
of quasar accretion disks, (3) determine the dark matter content of
the lensing galaxies, and (4) measure the stellar mass-to-light ratio
(in fact, this is the only way to measure the stellar mass-to-light
ratio beyond the solar neighborhood). In all cases, the main source of
uncertainty in our results is the small size of the sample of known
quads; only about 15 systems had been available for study with Chandra
unti the past year or two. New, large-area sky surveys have produced a
trove of new quads, and timely Chandra observations will allow for
great progress. We aim to propose such observations in the coming
cycle and seek to assess the unknown X-ray flux now in order to
propose the most efficient GO program.

Sequence Number: 703837

Title : Timely Assessment of the X-ray Flux of Newly Discovered Quadruply
Lensed Quasars
PI: Pooley
Abstract: Our previous work has shown the unique power of Chandra observations
of quadruply gravitationally lensed quasars to address several
fundamental astrophysical issues. We have used these observations to
(1) determine the cause of flux ratio anomalies, (2) measure the sizes
of quasar accretion disks, (3) determine the dark matter content of
the lensing galaxies, and (4) measure the stellar mass-to-light ratio
(in fact, this is the only way to measure the stellar mass-to-light
ratio beyond the solar neighborhood). In all cases, the main source of
uncertainty in our results is the small size of the sample of known
quads; only about 15 systems had been available for study with Chandra
unti the past year or two. New, large-area sky surveys have produced a
trove of new quads, and timely Chandra observations will allow for
great progress. We aim to propose such observations in the coming
cycle and seek to assess the unknown X-ray flux now in order to
propose the most efficient GO program.

Sequence Number: 703836

Title : Timely Assessment of the X-ray Flux of Newly Discovered Quadruply
Lensed Quasars
PI: Pooley
Abstract: Our previous work has shown the unique power of Chandra observations
of quadruply gravitationally lensed quasars to address several
fundamental astrophysical issues. We have used these observations to
(1) determine the cause of flux ratio anomalies, (2) measure the sizes
of quasar accretion disks, (3) determine the dark matter content of
the lensing galaxies, and (4) measure the stellar mass-to-light ratio
(in fact, this is the only way to measure the stellar mass-to-light
ratio beyond the solar neighborhood). In all cases, the main source of
uncertainty in our results is the small size of the sample of known
quads; only about 15 systems had been available for study with Chandra
unti the past year or two. New, large-area sky surveys have produced a
trove of new quads, and timely Chandra observations will allow for
great progress. We aim to propose such observations in the coming
cycle and seek to assess the unknown X-ray flux now in order to
propose the most efficient GO program.

Sequence Number: 703835

Title : Timely Assessment of the X-ray Flux of Newly Discovered Quadruply
Lensed Quasars
PI: Pooley
Abstract: Our previous work has shown the unique power of Chandra observations
of quadruply gravitationally lensed quasars to address several
fundamental astrophysical issues. We have used these observations to
(1) determine the cause of flux ratio anomalies, (2) measure the sizes
of quasar accretion disks, (3) determine the dark matter content of
the lensing galaxies, and (4) measure the stellar mass-to-light ratio
(in fact, this is the only way to measure the stellar mass-to-light
ratio beyond the solar neighborhood). In all cases, the main source of
uncertainty in our results is the small size of the sample of known
quads; only about 15 systems had been available for study with Chandra
unti the past year or two. New, large-area sky surveys have produced a
trove of new quads, and timely Chandra observations will allow for
great progress. We aim to propose such observations in the coming
cycle and seek to assess the unknown X-ray flux now in order to
propose the most efficient GO program.

Sequence Number: 703834

Title : Timely Assessment of the X-ray Flux of Newly Discovered Quadruply
Lensed Quasars
PI: Pooley
Abstract: Our previous work has shown the unique power of Chandra observations
of quadruply gravitationally lensed quasars to address several
fundamental astrophysical issues. We have used these observations to
(1) determine the cause of flux ratio anomalies, (2) measure the sizes
of quasar accretion disks, (3) determine the dark matter content of
the lensing galaxies, and (4) measure the stellar mass-to-light ratio
(in fact, this is the only way to measure the stellar mass-to-light
ratio beyond the solar neighborhood). In all cases, the main source of
uncertainty in our results is the small size of the sample of known
quads; only about 15 systems had been available for study with Chandra
unti the past year or two. New, large-area sky surveys have produced a
trove of new quads, and timely Chandra observations will allow for
great progress. We aim to propose such observations in the coming
cycle and seek to assess the unknown X-ray flux now in order to
propose the most efficient GO program.

Sequence Number: 703833

Title : Timely Assessment of the X-ray Flux of Newly Discovered Quadruply
Lensed Quasars
PI: Pooley
Abstract: Our previous work has shown the unique power of Chandra observations
of quadruply gravitationally lensed quasars to address several
fundamental astrophysical issues. We have used these observations to
(1) determine the cause of flux ratio anomalies, (2) measure the sizes
of quasar accretion disks, (3) determine the dark matter content of
the lensing galaxies, and (4) measure the stellar mass-to-light ratio
(in fact, this is the only way to measure the stellar mass-to-light
ratio beyond the solar neighborhood). In all cases, the main source of
uncertainty in our results is the small size of the sample of known
quads; only about 15 systems had been available for study with Chandra
unti the past year or two. New, large-area sky surveys have produced a
trove of new quads, and timely Chandra observations will allow for
great progress. We aim to propose such observations in the coming
cycle and seek to assess the unknown X-ray flux now in order to
propose the most efficient GO program.

Sequence Number: 201264

Title : A disk event in an Oe star
PI: Rauw
Abstract: Massive stars, including those with decretion disks (i.e. Oe and Be
stars), have an intrinsic X-ray emission linked to shocks in their
unstable winds with kT~0.6keV & log(Lx/Lbol)~-7. However,gamma-Cas
objects, named after their prototype, are substantially X-ray brighter
and emit harder X-rays. The origin of their high-energy emission
remains debated, but our recent observation of HD45314 during a
dissipation of its disk revealed an exceptional event: the X-ray
mission went 'back to normal', underlining the key role of the disk in
this poorly known phenomenon. However, to fully constrain it, the
inverse process (a 'normal' star becoming gamma-Cas) should also be
detected... but it has never been reported before.

Sequence Number: 402113

Title : A multi-wavelength ATCA/GAIA/Chandra search for the weakest Jets
PI: Reynolds
Abstract: Herein, we propose to obtain a 20ks Chandra imaging spectroscopy
observation of the dynamically confirmed BH GS 1354-64 to occur
quasi-simultaneously with an approved and scheduled ATCA radio
observation. Previous Chandra studies have revealed an anomalous high
luminosity quiescent accretion flow in this source (Reynolds et al.
2011). A new lower distance to the source has been proposed based on
GAIA parallax measurements (Gandhi et al. 2018). This new distance
would resolve the X-ray luminosity issue if the distance is closer to
2 kpc. At the GAIA distance the radio jet is easily within reach by
ATCA. A radio detection will provide valuable information on the
correct distance, and an additional constraint on the radio/X-ray
correlation at the lowest luminosities. Quiescent BHXBs are known to
be highly variable (F_var~60% in both the X-ray and radio), such that
a rigorous interpretation of a radio detection is impossible without
contemporaneous constraints on the X-ray flux.

Sequence Number: 402112

Title : Verifying a hyperluminous X-ray source in the spectroscopically
studied young starburst ESO 338-IG04
PI: Oskinova
Abstract: The enigmatic hyperluminous X-ray sources (HLXs) are off-nuclear point
sources with Lx> 10^{41} erg/s. HLXs probe different population of
compact objects compared to other accretors, and likely contain
intermediate mass black holes. Only a handful of HLX candidates is
known. The identification of a HLX in a galaxy with well characterized
stellar populations is the key to unlock a range of astrophysical
problems, such as the escape of ionizing radiation, stellar feedback,
double black hole formation, intermediate mass black holes in star
clusters, the lowest AGN masses and luminosities. From XMM images we
found that the low-metallicity starburst galaxy ESO 338-IG04 hosts a
candidate HLX. The stellar population of ESO 338-IG04 is already
thoroughly investigated thanks to the integral field spectroscopy with
MUSE at ESO VLT (Bik et al. 2018 arXiv:1809.03597). Here we seek to
determine the X-ray position of the new HLX and unambiguously identify
its optical counterpart.

Sequence Number: 201263

Title : Characterizing the X-ray Driven Chemistry of Protoplanetary Disks in
Orion
PI: Cleeves
Abstract: Young stars are surrounded by molecule-rich protoplanetary disks whose
chemistry is expected to evolve slowly, over ~Myr. Hence, we were
surprised to discover variability in H13CO+ J=3-2 emission from the IM
Lup disk between 3 observations taken over one year. This molecule is
X-ray sensitive, and a natural explanation is that stellar X-ray
flares may drive large changes in the disk composition. We have
followed up on a second source, DM Tau, and indeed see variations
consistent with X-ray driven disk chemistry but still lack the
"smoking gun" of an X-ray flare preceding H13CO+ variability. We have
recently obtained Swift and ALMA time to monitor 10 disks in Orion,
and here propose to obtain X-ray spectral shape info with Chandra.
Using simulations, we estimate a 93% probability of seeing H13CO+
variability preceded by an X-ray change for at least one source in our
sample. If confirmed, these observations will be the start of an
entirely new field of time-domain astrochemistry.

Sequence Number: 201262

Title : Characterizing the X-ray Driven Chemistry of Protoplanetary Disks in
Orion
PI: Cleeves
Abstract: Young stars are surrounded by molecule-rich protoplanetary disks whose
chemistry is expected to evolve slowly, over ~Myr. Hence, we were
surprised to discover variability in H13CO+ J=3-2 emission from the IM
Lup disk between 3 observations taken over one year. This molecule is
X-ray sensitive, and a natural explanation is that stellar X-ray
flares may drive large changes in the disk composition. We have
followed up on a second source, DM Tau, and indeed see variations
consistent with X-ray driven disk chemistry but still lack the
"smoking gun" of an X-ray flare preceding H13CO+ variability. We have
recently obtained Swift and ALMA time to monitor 10 disks in Orion,
and here propose to obtain X-ray spectral shape info with Chandra.
Using simulations, we estimate a 93% probability of seeing H13CO+
variability preceded by an X-ray change for at least one source in our
sample. If confirmed, these observations will be the start of an
entirely new field of time-domain astrochemistry.

Sequence Number: 703832

Title : Witnessing the Birth of a Blazar
PI: Paliya
Abstract: Gamma-ray detected narrow line Seyfert 1 (g-NLSy1s) galaxies are the
missing link between radio-quiet AGN and blazars. It is tedious to
study the host galaxy environment in blazars due to their jet
dominated emission. Therefore, g-NLSy1s, being lower jet power
objects, are the only beamed AGNs to unravel the jet-host galaxy
interaction. We have imaged the host of a g-NLSy1, TXS 2116-077, with
Subaru telescope and have discovered that the host is in the act of
merging with a nearby faint AGN (sep ~3", https://goo.gl/xdc1nZ).
Theoretically, it has been predicted that most jets are triggered by
mergers but this would be the very first observational evidence of it.
TXS 2116-077, thus, is a rare AGN to verify the theories of the jet
triggering mechanism. Our immediate objectives are: (i) determine the
X-ray morphology of the merging system and perform a spatially
resolved X-ray spectral analysis, and (ii) identify the nature of the
second nucleus (obscured/unobscured).

Sequence Number: 300461

Title : Target Confirmation for the Great Observatories Accretion Legacy
Survey
PI: Knigge
Abstract: Accretion disks power YSOs, LMXBs, CVs and AGN. The accretion process
often proceeds in bursts, during which systems brighten dramatically.
Remarkably, all transient disk-accretors share common observational
signatures: distinct spectral states, collimated jets, powerful disk
winds and analogous variability. To uncover the universal physics
behind this shared phenomenology, we are planning the Great
Observatories Accretion Legacy Survey. GOALS will observe a
disk-accreting system through a full outburst, with near-continuous
panchromatic coverage from X-ray to radio wavelengths. A viable target
for GOALS must (i) exhibit repeatable outbursts of suitable duration,
and (ii) be bright in all relevant bands. Only transiently accreting
CVs satisfy (i). Satisfying (ii) then requires a CV with detectable
EUV (critical for the soft state in CVs) and radio emission (the only
way to detect jets). Here, we propose a confirm the EUV suitability
(for LETG) of the only viable target we know.

Sequence Number: 503140

Title : The Compact Remnant in the Extraordinary Type Ib SN 2012au
PI: Patnaude
Abstract: Models of hydrogen-poor and energetic core-collapse supernovae often
invoke engine-driven mechanisms associated with the formation of
compact objects that input energy into the explosion. Determining
whether black holes or neutron stars play key roles in these
explosions remains contentious, as only circumstantial evidence of
their formation can be obtained when the explosion is most luminous. A
recent Magellan IMACS spectrum of the Type Ib SN 2012au revealed the
presence of photoionized, low velocity (2000 km/s) ejecta, with no
evidence for emission from the outer layers of fast moving ejecta. We
hypothesize that the inner layers of ejecta are being energized by a
luminous central source formed during the supernova. X-ray
observations will test this hypothesis. If the optical emission arises
from circumstellar interaction, it should be accompanied by X-rays
from shocked material. A non-detection will strengthen our argument
that the ejecta are energized by a central source.

Sequence Number: 503053

Title : A possible off-axis GRB in a nearby galaxy
PI: Maccarone
Abstract: This object is a bright X-ray transient in a galaxy at 60 Mpc,
consistent with expectations for a GRB afterglow, but without a GRB
having been seen. Its X-ray spectrum is harder than Gamma=2, but its
X-ray flux is below its optical flux, meaning that these are two
separate components. We thus need to extend the continuum in the
X-rays to get an idea of where the spectral curvature is.
Unfortunately, it cannot be observed by NuSTAR or INTEGRAL right now,
but fortunately it is bright enough to extend down in energy a factor
of 5 by using the LETG. We will also look for emission lines that
might indicate an optically think outflow and absorption lines that
might help characterize its local ISM.

Sequence Number: 201206

Title : Beyond the Coronal Graveyard
PI: AYRES
Abstract: Iconic Arcturus is member of a populous class of low-mass red giants
whose warm winds are a life-blood of Galactic ecology. How their mass
outflows are powered has remained elusive. A solar-like coronal wind
seemed unlikely, because the red giants have a very low incidence of
high-energy detections. In fact, Arcturus, itself, is one of the
weakest X-ray sources known among the bright cool stars. An intriguing
possibility is that red giants do have significant magnetic activity
and coronae, but mostly hidden beneath their puffy chromospheres.
Unfortunately, the X-ray spectra that could test the "buried corona"
conjecture are beyond reach of contemporary facilities. However, a
new, robust X-ray detection of Arcturus would inform the next
generation of high-energy observatories, whether such advanced
measurements in fact would be feasible.

Sequence Number: 703679

Title : Probing the duty cycle of a nuclear intermediate mass black hole
accreting at the Eddington limit
PI: Chilingarian
Abstract: Intermediate mass black holes represent (IMBH) a missing block in the
understanding of supermassive black hole assembly. Their very
existence is still debated. Using comprehensive multi-wavelength data
mining we identified 305 IMBH candidates by searching AGN signatures
in optical spectra of 1 million galaxies from SDSS. In 2017 we
followed up two of the candidates with Chandra and detected bright
X-ray emission from one of them, which corresponded to the level close
to the Eddington limit for its mass (70k MSun). This is the least
massive known active central black hole that has an X-ray spectrum.
Here we propose to observe this source once again in order to get the
first insights on the duty cycle of an IMBH-powered AGN. In 10ksec we
expect 500 photons from the source if the luminosity is persistent,
which we suspect is true given the lack of optical variability of the
broad-line component of H-alpha.

Sequence Number: 703678

Title : Chandra observations of NGC3893: Completion of the Palomar Galaxies
Legacy Sample
PI: McHardy
Abstract: In proposal 18620515 we were awarded observations to complete Chandra
coverage, to 10ks per target, of ALL of the galaxies from the Palomar
bright nearby galaxies sample of Ho et al (1995) in the declination
range +40 to +65. This sample is widely regarded as the statistically
most complete sample of nearby galaxies and is the subject of 'legacy'
surveys in many bands. In particular we made high resolution (0.15
arcsec) eMERLIN radio observations of all the above galaxies, not just
those classed as active, as in other studies. Only Chandra provides
comparable X-ray resolution. Thus we should be able to study
relationships such as the radio/X-ray/BH mass 'fundamental plane', or
derive X-ray luminosity functions at very low luminosities, for
different galaxy types without any concerns regarding incompleteness.
We selected our Chandra sample to avoid duplication and erroneously
removed one galaxy. We here request one 10ks observation to make the
Chandra legacy sample 100% complete.

Sequence Number: 402025

Title : GW170817: Long term tracking of the the X-ray light curve.
PI: Wilkes
Abstract: This proposal is a merger of several DDT requests to follow-up the
NS-NS merger: GW170817.

Sequence Number: 402026

Title : Wind energetic and dust scattering halo in Swift J1658.2-4242
PI: Ponti
Abstract: SwiftJ1658.2-4242 is a newly discovered high inclination BH-XRB. We
obtained 5*30ks XMM+NuSTAR+3*30ks AstroSAT campaign following the
evolution of the wind and the accretion systems from the hard to the
soft intermediate state (Feb. 27-Mar. 27). The source shows never-seen
Compton thick dips and a behaviour observed only in few systems and of
unclear origin. This appears as sudden (<50s) drops/increases
(flip-flop) of the flux, with weak colour variations and non-periodic.
A QPO at 6Hz is observed at lower flux and it disappears at high flux.
A variable absorption line at ~7 keV +a relativistic FeK line are
observed to evolve during the outburst. We request a 30ks HETG
observation during the current soft state to: A) Determine the
energetics of the wind, investigate its relations with the states and
flip-flop behaviour; B) Disentangle absorption from relativistic line;
C) Detail the inner parts of the dust scattering halo; D) Determine
the amount of Iron depleted into dust grains.

Sequence Number: 503043

Title : Zeroing in on the Mass Loss Properties of Core Collapse Supernova
Progenitors
PI: Patnaude
Abstract: The mass loss history of massive stars is one of the least understood
yet fundamental aspects of stellar evolution. How and when do massive
stars shed their hydrogen envelopes? Is there a relationship between
the expulsion of the stellar envelope and core collapse? Is there a
fundamental relationship between late time mass loss and supernova
classification? These central, yet open questions motivate the
proposed Chandra Successor Mission program. In regards to these
questions, studying the evolution of a supernova shock, over
timescales of decades, as it interacts with the ejected envelope of
the progenitor, provides insight into how much mass was lost and
perhaps most importantly, when it was lost, prior to core collapse.
X-ray emission from the shocked gas probes the dynamics of the
interaction, and when combined with multiwavelength observations,
constrains properties of the surrounding circumstellar gas and thus
the later stages of the progenitor's evolution.

Sequence Number: 402025

Title : GW170817: Long term tracking of the the X-ray light curve.
PI: Wilkes
Abstract: This proposal is a merger of several DDT requests to follow-up the
NS-NS merger: GW170817.

Sequence Number: 703677

Title : Origin of the X-ray to TeV emission of the M87 AGN
PI: Wong
Abstract: M87 hosts a 3-6 billion solar mass black hole with an exceptional
relativistic jet. It has been regularly monitored in radio to TeV
bands, but little has been done in hard X-rays >10 keV. For the first
time, we have successfully detected hard X-rays up to 40 keV from its
X-ray core with joint Chandra and NuSTAR observations, providing
important insights to the X-ray origins (Wong et al. 2017): from the
unresolved jet or the accretion flow. We found that the hard X-ray
emission is significantly lower than that predicted by synchrotron
self-Compton models introduced to explain emission above a GeV. To
further understand these high energy processes, a key component is to
monitor the soft and hard X-ray emission and study their correlation.
Together with the Event Horizon Telescope, NuSTAR will observe M87 in
April 2018. We propose Chandra snapshots near the NuSTAR window, which
is essential to resolve the keV jet and to pin-point the location of
the high energy active site.

Sequence Number: 703676

Title : Origin of the X-ray to TeV emission of the M87 AGN
PI: Wong
Abstract: M87 hosts a 3-6 billion solar mass black hole with an exceptional
relativistic jet. It has been regularly monitored in radio to TeV
bands, but little has been done in hard X-rays >10 keV. For the first
time, we have successfully detected hard X-rays up to 40 keV from its
X-ray core with joint Chandra and NuSTAR observations, providing
important insights to the X-ray origins (Wong et al. 2017): from the
unresolved jet or the accretion flow. We found that the hard X-ray
emission is significantly lower than that predicted by synchrotron
self-Compton models introduced to explain emission above a GeV. To
further understand these high energy processes, a key component is to
monitor the soft and hard X-ray emission and study their correlation.
Together with the Event Horizon Telescope, NuSTAR will observe M87 in
April 2018. We propose Chandra snapshots near the NuSTAR window, which
is essential to resolve the keV jet and to pin-point the location of
the high energy active site.

Sequence Number: 703675

Title : Determining the emission region of VHE gamma-rays in radio galaxy 3C
264
PI: Santander
Abstract: We request DDT observations of the radio galaxy 3C 264, which VERITAS
is currently observing in an active state that has led to its first
detection in VHE gamma-rays. The analysis of the VHE observations is
on-going and VERITAS plans to perform a deep exposure of the object
over the coming days. This detection would represent the 6th radio
galaxy observed in VHE gamma rays. Radio galaxies are currently the
only non-blazar AGN detected in this band. As the jet of 3C 264 has
been resolved by Chandra, this detection presents a unique opportunity
to determine the location of the VHE gamma-ray emission region and
differentiate its origin with the core and inner jet, or the outer
resolved jet. A MWL campaign is being organized for the source.

Sequence Number: 503052

Title : MAPPING OUT THE EXPLOSIVE MASS-LOSS HISTORY OF THE IMPOSSIBLE SN
iPTF14hls
PI: MARGUTTI
Abstract: The stellar explosion iPTF14hls has been confusing the community for a
while, with a spectral and temporal evolution that could not be
reconciled under standard scenarios. However, iPTF14hls recently
experienced a complete spectral metamorphosis. This evolution suggests
that the solution to the puzzle might be the interaction of the
blastwave with an environment sculpted by the progenitor's eruptions
before the final explosion. If this is correct, iPTF14hls should
produce rising X-ray and radio emission in the next months. Here we
ask for CXO monitoring to test our interacting scenario.

Sequence Number: 703674

Title : LOW SURFACE BRIGHTNESS GALAXIES AND THE BLACK HOLE OCCUPATION
FRACTION
PI: Gallo
Abstract: We propose a snapshot survey of nearby low-surface brightness galaxies
(unbiased with respect to nuclear properties) to measure the rate and
incidence of low Eddington ratio nuclear X-ray emission and determine
how the nuclear L_X to mass (stellar and/or gas) relation in this
sample compares with that of normal, high surface brightness galaxies.
Results from this program will inform the galaxy selection function
needed towards a high accuracy black hole occupation fraction
measurement with Lynx. In turn, this will constrain the primary mode
for black hole seeding at high z, complementing efforts that will be
undertaken at high-z.

Sequence Number: 703673

Title : LOW SURFACE BRIGHTNESS GALAXIES AND THE BLACK HOLE OCCUPATION
FRACTION
PI: Gallo
Abstract: We propose a snapshot survey of nearby low-surface brightness galaxies
(unbiased with respect to nuclear properties) to measure the rate and
incidence of low Eddington ratio nuclear X-ray emission and determine
how the nuclear L_X to mass (stellar and/or gas) relation in this
sample compares with that of normal, high surface brightness galaxies.
Results from this program will inform the galaxy selection function
needed towards a high accuracy black hole occupation fraction
measurement with Lynx. In turn, this will constrain the primary mode
for black hole seeding at high z, complementing efforts that will be
undertaken at high-z.

Sequence Number: 703672

Title : LOW SURFACE BRIGHTNESS GALAXIES AND THE BLACK HOLE OCCUPATION
FRACTION
PI: Gallo
Abstract: We propose a snapshot survey of nearby low-surface brightness galaxies
(unbiased with respect to nuclear properties) to measure the rate and
incidence of low Eddington ratio nuclear X-ray emission and determine
how the nuclear L_X to mass (stellar and/or gas) relation in this
sample compares with that of normal, high surface brightness galaxies.
Results from this program will inform the galaxy selection function
needed towards a high accuracy black hole occupation fraction
measurement with Lynx. In turn, this will constrain the primary mode
for black hole seeding at high z, complementing efforts that will be
undertaken at high-z.

Sequence Number: 703671

Title : LOW SURFACE BRIGHTNESS GALAXIES AND THE BLACK HOLE OCCUPATION
FRACTION
PI: Gallo
Abstract: We propose a snapshot survey of nearby low-surface brightness galaxies
(unbiased with respect to nuclear properties) to measure the rate and
incidence of low Eddington ratio nuclear X-ray emission and determine
how the nuclear L_X to mass (stellar and/or gas) relation in this
sample compares with that of normal, high surface brightness galaxies.
Results from this program will inform the galaxy selection function
needed towards a high accuracy black hole occupation fraction
measurement with Lynx. In turn, this will constrain the primary mode
for black hole seeding at high z, complementing efforts that will be
undertaken at high-z.

Sequence Number: 703670

Title : LOW SURFACE BRIGHTNESS GALAXIES AND THE BLACK HOLE OCCUPATION
FRACTION
PI: Gallo
Abstract: We propose a snapshot survey of nearby low-surface brightness galaxies
(unbiased with respect to nuclear properties) to measure the rate and
incidence of low Eddington ratio nuclear X-ray emission and determine
how the nuclear L_X to mass (stellar and/or gas) relation in this
sample compares with that of normal, high surface brightness galaxies.
Results from this program will inform the galaxy selection function
needed towards a high accuracy black hole occupation fraction
measurement with Lynx. In turn, this will constrain the primary mode
for black hole seeding at high z, complementing efforts that will be
undertaken at high-z.

Sequence Number: 703669

Title : LOW SURFACE BRIGHTNESS GALAXIES AND THE BLACK HOLE OCCUPATION
FRACTION
PI: Gallo
Abstract: We propose a snapshot survey of nearby low-surface brightness galaxies
(unbiased with respect to nuclear properties) to measure the rate and
incidence of low Eddington ratio nuclear X-ray emission and determine
how the nuclear L_X to mass (stellar and/or gas) relation in this
sample compares with that of normal, high surface brightness galaxies.
Results from this program will inform the galaxy selection function
needed towards a high accuracy black hole occupation fraction
measurement with Lynx. In turn, this will constrain the primary mode
for black hole seeding at high z, complementing efforts that will be
undertaken at high-z.

Sequence Number: 703668

Title : LOW SURFACE BRIGHTNESS GALAXIES AND THE BLACK HOLE OCCUPATION
FRACTION
PI: Gallo
Abstract: We propose a snapshot survey of nearby low-surface brightness galaxies
(unbiased with respect to nuclear properties) to measure the rate and
incidence of low Eddington ratio nuclear X-ray emission and determine
how the nuclear L_X to mass (stellar and/or gas) relation in this
sample compares with that of normal, high surface brightness galaxies.
Results from this program will inform the galaxy selection function
needed towards a high accuracy black hole occupation fraction
measurement with Lynx. In turn, this will constrain the primary mode
for black hole seeding at high z, complementing efforts that will be
undertaken at high-z.

Sequence Number: 703667

Title : LOW SURFACE BRIGHTNESS GALAXIES AND THE BLACK HOLE OCCUPATION
FRACTION
PI: Gallo
Abstract: We propose a snapshot survey of nearby low-surface brightness galaxies
(unbiased with respect to nuclear properties) to measure the rate and
incidence of low Eddington ratio nuclear X-ray emission and determine
how the nuclear L_X to mass (stellar and/or gas) relation in this
sample compares with that of normal, high surface brightness galaxies.
Results from this program will inform the galaxy selection function
needed towards a high accuracy black hole occupation fraction
measurement with Lynx. In turn, this will constrain the primary mode
for black hole seeding at high z, complementing efforts that will be
undertaken at high-z.

Sequence Number: 703666

Title : LOW SURFACE BRIGHTNESS GALAXIES AND THE BLACK HOLE OCCUPATION
FRACTION
PI: Gallo
Abstract: We propose a snapshot survey of nearby low-surface brightness galaxies
(unbiased with respect to nuclear properties) to measure the rate and
incidence of low Eddington ratio nuclear X-ray emission and determine
how the nuclear L_X to mass (stellar and/or gas) relation in this
sample compares with that of normal, high surface brightness galaxies.
Results from this program will inform the galaxy selection function
needed towards a high accuracy black hole occupation fraction
measurement with Lynx. In turn, this will constrain the primary mode
for black hole seeding at high z, complementing efforts that will be
undertaken at high-z.

Sequence Number: 703665

Title : LOW SURFACE BRIGHTNESS GALAXIES AND THE BLACK HOLE OCCUPATION
FRACTION
PI: Gallo
Abstract: We propose a snapshot survey of nearby low-surface brightness galaxies
(unbiased with respect to nuclear properties) to measure the rate and
incidence of low Eddington ratio nuclear X-ray emission and determine
how the nuclear L_X to mass (stellar and/or gas) relation in this
sample compares with that of normal, high surface brightness galaxies.
Results from this program will inform the galaxy selection function
needed towards a high accuracy black hole occupation fraction
measurement with Lynx. In turn, this will constrain the primary mode
for black hole seeding at high z, complementing efforts that will be
undertaken at high-z.

Sequence Number: 703664

Title : LOW SURFACE BRIGHTNESS GALAXIES AND THE BLACK HOLE OCCUPATION
FRACTION
PI: Gallo
Abstract: We propose a snapshot survey of nearby low-surface brightness galaxies
(unbiased with respect to nuclear properties) to measure the rate and
incidence of low Eddington ratio nuclear X-ray emission and determine
how the nuclear L_X to mass (stellar and/or gas) relation in this
sample compares with that of normal, high surface brightness galaxies.
Results from this program will inform the galaxy selection function
needed towards a high accuracy black hole occupation fraction
measurement with Lynx. In turn, this will constrain the primary mode
for black hole seeding at high z, complementing efforts that will be
undertaken at high-z.

Sequence Number: 703663

Title : LOW SURFACE BRIGHTNESS GALAXIES AND THE BLACK HOLE OCCUPATION
FRACTION
PI: Gallo
Abstract: We propose a snapshot survey of nearby low-surface brightness galaxies
(unbiased with respect to nuclear properties) to measure the rate and
incidence of low Eddington ratio nuclear X-ray emission and determine
how the nuclear L_X to mass (stellar and/or gas) relation in this
sample compares with that of normal, high surface brightness galaxies.
Results from this program will inform the galaxy selection function
needed towards a high accuracy black hole occupation fraction
measurement with Lynx. In turn, this will constrain the primary mode
for black hole seeding at high z, complementing efforts that will be
undertaken at high-z.

Sequence Number: 703662

Title : LOW SURFACE BRIGHTNESS GALAXIES AND THE BLACK HOLE OCCUPATION
FRACTION
PI: Gallo
Abstract: We propose a snapshot survey of nearby low-surface brightness galaxies
(unbiased with respect to nuclear properties) to measure the rate and
incidence of low Eddington ratio nuclear X-ray emission and determine
how the nuclear L_X to mass (stellar and/or gas) relation in this
sample compares with that of normal, high surface brightness galaxies.
Results from this program will inform the galaxy selection function
needed towards a high accuracy black hole occupation fraction
measurement with Lynx. In turn, this will constrain the primary mode
for black hole seeding at high z, complementing efforts that will be
undertaken at high-z.

Sequence Number: 703661

Title : LOW SURFACE BRIGHTNESS GALAXIES AND THE BLACK HOLE OCCUPATION
FRACTION
PI: Gallo
Abstract: We propose a snapshot survey of nearby low-surface brightness galaxies
(unbiased with respect to nuclear properties) to measure the rate and
incidence of low Eddington ratio nuclear X-ray emission and determine
how the nuclear L_X to mass (stellar and/or gas) relation in this
sample compares with that of normal, high surface brightness galaxies.
Results from this program will inform the galaxy selection function
needed towards a high accuracy black hole occupation fraction
measurement with Lynx. In turn, this will constrain the primary mode
for black hole seeding at high z, complementing efforts that will be
undertaken at high-z.

Sequence Number: 703660

Title : LOW SURFACE BRIGHTNESS GALAXIES AND THE BLACK HOLE OCCUPATION
FRACTION
PI: Gallo
Abstract: We propose a snapshot survey of nearby low-surface brightness galaxies
(unbiased with respect to nuclear properties) to measure the rate and
incidence of low Eddington ratio nuclear X-ray emission and determine
how the nuclear L_X to mass (stellar and/or gas) relation in this
sample compares with that of normal, high surface brightness galaxies.
Results from this program will inform the galaxy selection function
needed towards a high accuracy black hole occupation fraction
measurement with Lynx. In turn, this will constrain the primary mode
for black hole seeding at high z, complementing efforts that will be
undertaken at high-z.

Sequence Number: 703659

Title : LOW SURFACE BRIGHTNESS GALAXIES AND THE BLACK HOLE OCCUPATION
FRACTION
PI: Gallo
Abstract: We propose a snapshot survey of nearby low-surface brightness galaxies
(unbiased with respect to nuclear properties) to measure the rate and
incidence of low Eddington ratio nuclear X-ray emission and determine
how the nuclear L_X to mass (stellar and/or gas) relation in this
sample compares with that of normal, high surface brightness galaxies.
Results from this program will inform the galaxy selection function
needed towards a high accuracy black hole occupation fraction
measurement with Lynx. In turn, this will constrain the primary mode
for black hole seeding at high z, complementing efforts that will be
undertaken at high-z.

Sequence Number: 703658

Title : LOW SURFACE BRIGHTNESS GALAXIES AND THE BLACK HOLE OCCUPATION
FRACTION
PI: Gallo
Abstract: We propose a snapshot survey of nearby low-surface brightness galaxies
(unbiased with respect to nuclear properties) to measure the rate and
incidence of low Eddington ratio nuclear X-ray emission and determine
how the nuclear L_X to mass (stellar and/or gas) relation in this
sample compares with that of normal, high surface brightness galaxies.
Results from this program will inform the galaxy selection function
needed towards a high accuracy black hole occupation fraction
measurement with Lynx. In turn, this will constrain the primary mode
for black hole seeding at high z, complementing efforts that will be
undertaken at high-z.

Sequence Number: 703657

Title : LOW SURFACE BRIGHTNESS GALAXIES AND THE BLACK HOLE OCCUPATION
FRACTION
PI: Gallo
Abstract: We propose a snapshot survey of nearby low-surface brightness galaxies
(unbiased with respect to nuclear properties) to measure the rate and
incidence of low Eddington ratio nuclear X-ray emission and determine
how the nuclear L_X to mass (stellar and/or gas) relation in this
sample compares with that of normal, high surface brightness galaxies.
Results from this program will inform the galaxy selection function
needed towards a high accuracy black hole occupation fraction
measurement with Lynx. In turn, this will constrain the primary mode
for black hole seeding at high z, complementing efforts that will be
undertaken at high-z.

Sequence Number: 703656

Title : LOW SURFACE BRIGHTNESS GALAXIES AND THE BLACK HOLE OCCUPATION
FRACTION
PI: Gallo
Abstract: We propose a snapshot survey of nearby low-surface brightness galaxies
(unbiased with respect to nuclear properties) to measure the rate and
incidence of low Eddington ratio nuclear X-ray emission and determine
how the nuclear L_X to mass (stellar and/or gas) relation in this
sample compares with that of normal, high surface brightness galaxies.
Results from this program will inform the galaxy selection function
needed towards a high accuracy black hole occupation fraction
measurement with Lynx. In turn, this will constrain the primary mode
for black hole seeding at high z, complementing efforts that will be
undertaken at high-z.

Sequence Number: 703655

Title : LOW SURFACE BRIGHTNESS GALAXIES AND THE BLACK HOLE OCCUPATION
FRACTION
PI: Gallo
Abstract: We propose a snapshot survey of nearby low-surface brightness galaxies
(unbiased with respect to nuclear properties) to measure the rate and
incidence of low Eddington ratio nuclear X-ray emission and determine
how the nuclear L_X to mass (stellar and/or gas) relation in this
sample compares with that of normal, high surface brightness galaxies.
Results from this program will inform the galaxy selection function
needed towards a high accuracy black hole occupation fraction
measurement with Lynx. In turn, this will constrain the primary mode
for black hole seeding at high z, complementing efforts that will be
undertaken at high-z.

Sequence Number: 703654

Title : LOW SURFACE BRIGHTNESS GALAXIES AND THE BLACK HOLE OCCUPATION
FRACTION
PI: Gallo
Abstract: We propose a snapshot survey of nearby low-surface brightness galaxies
(unbiased with respect to nuclear properties) to measure the rate and
incidence of low Eddington ratio nuclear X-ray emission and determine
how the nuclear L_X to mass (stellar and/or gas) relation in this
sample compares with that of normal, high surface brightness galaxies.
Results from this program will inform the galaxy selection function
needed towards a high accuracy black hole occupation fraction
measurement with Lynx. In turn, this will constrain the primary mode
for black hole seeding at high z, complementing efforts that will be
undertaken at high-z.

Sequence Number: 703653

Title : LOW SURFACE BRIGHTNESS GALAXIES AND THE BLACK HOLE OCCUPATION
FRACTION
PI: Gallo
Abstract: We propose a snapshot survey of nearby low-surface brightness galaxies
(unbiased with respect to nuclear properties) to measure the rate and
incidence of low Eddington ratio nuclear X-ray emission and determine
how the nuclear L_X to mass (stellar and/or gas) relation in this
sample compares with that of normal, high surface brightness galaxies.
Results from this program will inform the galaxy selection function
needed towards a high accuracy black hole occupation fraction
measurement with Lynx. In turn, this will constrain the primary mode
for black hole seeding at high z, complementing efforts that will be
undertaken at high-z.

Sequence Number: 703652

Title : LOW SURFACE BRIGHTNESS GALAXIES AND THE BLACK HOLE OCCUPATION
FRACTION
PI: Gallo
Abstract: We propose a snapshot survey of nearby low-surface brightness galaxies
(unbiased with respect to nuclear properties) to measure the rate and
incidence of low Eddington ratio nuclear X-ray emission and determine
how the nuclear L_X to mass (stellar and/or gas) relation in this
sample compares with that of normal, high surface brightness galaxies.
Results from this program will inform the galaxy selection function
needed towards a high accuracy black hole occupation fraction
measurement with Lynx. In turn, this will constrain the primary mode
for black hole seeding at high z, complementing efforts that will be
undertaken at high-z.

Sequence Number: 703651

Title : LOW SURFACE BRIGHTNESS GALAXIES AND THE BLACK HOLE OCCUPATION
FRACTION
PI: Gallo
Abstract: We propose a snapshot survey of nearby low-surface brightness galaxies
(unbiased with respect to nuclear properties) to measure the rate and
incidence of low Eddington ratio nuclear X-ray emission and determine
how the nuclear L_X to mass (stellar and/or gas) relation in this
sample compares with that of normal, high surface brightness galaxies.
Results from this program will inform the galaxy selection function
needed towards a high accuracy black hole occupation fraction
measurement with Lynx. In turn, this will constrain the primary mode
for black hole seeding at high z, complementing efforts that will be
undertaken at high-z.

Sequence Number: 703650

Title : LOW SURFACE BRIGHTNESS GALAXIES AND THE BLACK HOLE OCCUPATION
FRACTION
PI: Gallo
Abstract: We propose a snapshot survey of nearby low-surface brightness galaxies
(unbiased with respect to nuclear properties) to measure the rate and
incidence of low Eddington ratio nuclear X-ray emission and determine
how the nuclear L_X to mass (stellar and/or gas) relation in this
sample compares with that of normal, high surface brightness galaxies.
Results from this program will inform the galaxy selection function
needed towards a high accuracy black hole occupation fraction
measurement with Lynx. In turn, this will constrain the primary mode
for black hole seeding at high z, complementing efforts that will be
undertaken at high-z.

Sequence Number: 703649

Title : LOW SURFACE BRIGHTNESS GALAXIES AND THE BLACK HOLE OCCUPATION
FRACTION
PI: Gallo
Abstract: We propose a snapshot survey of nearby low-surface brightness galaxies
(unbiased with respect to nuclear properties) to measure the rate and
incidence of low Eddington ratio nuclear X-ray emission and determine
how the nuclear L_X to mass (stellar and/or gas) relation in this
sample compares with that of normal, high surface brightness galaxies.
Results from this program will inform the galaxy selection function
needed towards a high accuracy black hole occupation fraction
measurement with Lynx. In turn, this will constrain the primary mode
for black hole seeding at high z, complementing efforts that will be
undertaken at high-z.

Sequence Number: 703648

Title : LOW SURFACE BRIGHTNESS GALAXIES AND THE BLACK HOLE OCCUPATION
FRACTION
PI: Gallo
Abstract: We propose a snapshot survey of nearby low-surface brightness galaxies
(unbiased with respect to nuclear properties) to measure the rate and
incidence of low Eddington ratio nuclear X-ray emission and determine
how the nuclear L_X to mass (stellar and/or gas) relation in this
sample compares with that of normal, high surface brightness galaxies.
Results from this program will inform the galaxy selection function
needed towards a high accuracy black hole occupation fraction
measurement with Lynx. In turn, this will constrain the primary mode
for black hole seeding at high z, complementing efforts that will be
undertaken at high-z.

Sequence Number: 703647

Title : LOW SURFACE BRIGHTNESS GALAXIES AND THE BLACK HOLE OCCUPATION
FRACTION
PI: Gallo
Abstract: We propose a snapshot survey of nearby low-surface brightness galaxies
(unbiased with respect to nuclear properties) to measure the rate and
incidence of low Eddington ratio nuclear X-ray emission and determine
how the nuclear L_X to mass (stellar and/or gas) relation in this
sample compares with that of normal, high surface brightness galaxies.
Results from this program will inform the galaxy selection function
needed towards a high accuracy black hole occupation fraction
measurement with Lynx. In turn, this will constrain the primary mode
for black hole seeding at high z, complementing efforts that will be
undertaken at high-z.

Sequence Number: 503051

Title : Zeroing in on the Mass Loss Properties of Core Collapse Supernova
Progenitors
PI: Patnaude
Abstract: The mass loss history of massive stars is one of the least understood
yet fundamental aspects of stellar evolution. How and when do massive
stars shed their hydrogen envelopes? Is there a relationship between
the expulsion of the stellar envelope and core collapse? Is there a
fundamental relationship between late time mass loss and supernova
classification? These central, yet open questions motivate the
proposed Chandra Successor Mission program. In regards to these
questions, studying the evolution of a supernova shock, over
timescales of decades, as it interacts with the ejected envelope of
the progenitor, provides insight into how much mass was lost and
perhaps most importantly, when it was lost, prior to core collapse.
X-ray emission from the shocked gas probes the dynamics of the
interaction, and when combined with multiwavelength observations,
constrains properties of the surrounding circumstellar gas and thus
the later stages of the progenitor's evolution.

Sequence Number: 503050

Title : Zeroing in on the Mass Loss Properties of Core Collapse Supernova
Progenitors
PI: Patnaude
Abstract: The mass loss history of massive stars is one of the least understood
yet fundamental aspects of stellar evolution. How and when do massive
stars shed their hydrogen envelopes? Is there a relationship between
the expulsion of the stellar envelope and core collapse? Is there a
fundamental relationship between late time mass loss and supernova
classification? These central, yet open questions motivate the
proposed Chandra Successor Mission program. In regards to these
questions, studying the evolution of a supernova shock, over
timescales of decades, as it interacts with the ejected envelope of
the progenitor, provides insight into how much mass was lost and
perhaps most importantly, when it was lost, prior to core collapse.
X-ray emission from the shocked gas probes the dynamics of the
interaction, and when combined with multiwavelength observations,
constrains properties of the surrounding circumstellar gas and thus
the later stages of the progenitor's evolution.

Sequence Number: 503049

Title : Zeroing in on the Mass Loss Properties of Core Collapse Supernova
Progenitors
PI: Patnaude
Abstract: The mass loss history of massive stars is one of the least understood
yet fundamental aspects of stellar evolution. How and when do massive
stars shed their hydrogen envelopes? Is there a relationship between
the expulsion of the stellar envelope and core collapse? Is there a
fundamental relationship between late time mass loss and supernova
classification? These central, yet open questions motivate the
proposed Chandra Successor Mission program. In regards to these
questions, studying the evolution of a supernova shock, over
timescales of decades, as it interacts with the ejected envelope of
the progenitor, provides insight into how much mass was lost and
perhaps most importantly, when it was lost, prior to core collapse.
X-ray emission from the shocked gas probes the dynamics of the
interaction, and when combined with multiwavelength observations,
constrains properties of the surrounding circumstellar gas and thus
the later stages of the progenitor's evolution.

Sequence Number: 503048

Title : Zeroing in on the Mass Loss Properties of Core Collapse Supernova
Progenitors
PI: Patnaude
Abstract: The mass loss history of massive stars is one of the least understood
yet fundamental aspects of stellar evolution. How and when do massive
stars shed their hydrogen envelopes? Is there a relationship between
the expulsion of the stellar envelope and core collapse? Is there a
fundamental relationship between late time mass loss and supernova
classification? These central, yet open questions motivate the
proposed Chandra Successor Mission program. In regards to these
questions, studying the evolution of a supernova shock, over
timescales of decades, as it interacts with the ejected envelope of
the progenitor, provides insight into how much mass was lost and
perhaps most importantly, when it was lost, prior to core collapse.
X-ray emission from the shocked gas probes the dynamics of the
interaction, and when combined with multiwavelength observations,
constrains properties of the surrounding circumstellar gas and thus
the later stages of the progenitor's evolution.

Sequence Number: 503047

Title : Zeroing in on the Mass Loss Properties of Core Collapse Supernova
Progenitors
PI: Patnaude
Abstract: The mass loss history of massive stars is one of the least understood
yet fundamental aspects of stellar evolution. How and when do massive
stars shed their hydrogen envelopes? Is there a relationship between
the expulsion of the stellar envelope and core collapse? Is there a
fundamental relationship between late time mass loss and supernova
classification? These central, yet open questions motivate the
proposed Chandra Successor Mission program. In regards to these
questions, studying the evolution of a supernova shock, over
timescales of decades, as it interacts with the ejected envelope of
the progenitor, provides insight into how much mass was lost and
perhaps most importantly, when it was lost, prior to core collapse.
X-ray emission from the shocked gas probes the dynamics of the
interaction, and when combined with multiwavelength observations,
constrains properties of the surrounding circumstellar gas and thus
the later stages of the progenitor's evolution.

Sequence Number: 503046

Title : Zeroing in on the Mass Loss Properties of Core Collapse Supernova
Progenitors
PI: Patnaude
Abstract: The mass loss history of massive stars is one of the least understood
yet fundamental aspects of stellar evolution. How and when do massive
stars shed their hydrogen envelopes? Is there a relationship between
the expulsion of the stellar envelope and core collapse? Is there a
fundamental relationship between late time mass loss and supernova
classification? These central, yet open questions motivate the
proposed Chandra Successor Mission program. In regards to these
questions, studying the evolution of a supernova shock, over
timescales of decades, as it interacts with the ejected envelope of
the progenitor, provides insight into how much mass was lost and
perhaps most importantly, when it was lost, prior to core collapse.
X-ray emission from the shocked gas probes the dynamics of the
interaction, and when combined with multiwavelength observations,
constrains properties of the surrounding circumstellar gas and thus
the later stages of the progenitor's evolution.

Sequence Number: 503045

Title : Zeroing in on the Mass Loss Properties of Core Collapse Supernova
Progenitors
PI: Patnaude
Abstract: The mass loss history of massive stars is one of the least understood
yet fundamental aspects of stellar evolution. How and when do massive
stars shed their hydrogen envelopes? Is there a relationship between
the expulsion of the stellar envelope and core collapse? Is there a
fundamental relationship between late time mass loss and supernova
classification? These central, yet open questions motivate the
proposed Chandra Successor Mission program. In regards to these
questions, studying the evolution of a supernova shock, over
timescales of decades, as it interacts with the ejected envelope of
the progenitor, provides insight into how much mass was lost and
perhaps most importantly, when it was lost, prior to core collapse.
X-ray emission from the shocked gas probes the dynamics of the
interaction, and when combined with multiwavelength observations,
constrains properties of the surrounding circumstellar gas and thus
the later stages of the progenitor's evolution.

Sequence Number: 503044

Title : Zeroing in on the Mass Loss Properties of Core Collapse Supernova
Progenitors
PI: Patnaude
Abstract: The mass loss history of massive stars is one of the least understood
yet fundamental aspects of stellar evolution. How and when do massive
stars shed their hydrogen envelopes? Is there a relationship between
the expulsion of the stellar envelope and core collapse? Is there a
fundamental relationship between late time mass loss and supernova
classification? These central, yet open questions motivate the
proposed Chandra Successor Mission program. In regards to these
questions, studying the evolution of a supernova shock, over
timescales of decades, as it interacts with the ejected envelope of
the progenitor, provides insight into how much mass was lost and
perhaps most importantly, when it was lost, prior to core collapse.
X-ray emission from the shocked gas probes the dynamics of the
interaction, and when combined with multiwavelength observations,
constrains properties of the surrounding circumstellar gas and thus
the later stages of the progenitor's evolution.

Sequence Number: 503043

Title : Zeroing in on the Mass Loss Properties of Core Collapse Supernova
Progenitors
PI: Patnaude
Abstract: The mass loss history of massive stars is one of the least understood
yet fundamental aspects of stellar evolution. How and when do massive
stars shed their hydrogen envelopes? Is there a relationship between
the expulsion of the stellar envelope and core collapse? Is there a
fundamental relationship between late time mass loss and supernova
classification? These central, yet open questions motivate the
proposed Chandra Successor Mission program. In regards to these
questions, studying the evolution of a supernova shock, over
timescales of decades, as it interacts with the ejected envelope of
the progenitor, provides insight into how much mass was lost and
perhaps most importantly, when it was lost, prior to core collapse.
X-ray emission from the shocked gas probes the dynamics of the
interaction, and when combined with multiwavelength observations,
constrains properties of the surrounding circumstellar gas and thus
the later stages of the progenitor's evolution.

Sequence Number: 201206

Title : Beyond the Coronal Graveyard
PI: AYRES
Abstract: Iconic Arcturus is member of a populous class of low-mass red giants
whose warm winds are a life-blood of Galactic ecology. How their mass
outflows are powered has remained elusive. A solar-like coronal wind
seemed unlikely, because the red giants have a very low incidence of
high-energy detections. In fact, Arcturus, itself, is one of the
weakest X-ray sources known among the bright cool stars. An intriguing
possibility is that red giants do have significant magnetic activity
and coronae, but mostly hidden beneath their puffy chromospheres.
Unfortunately, the X-ray spectra that could test the "buried corona"
conjecture are beyond reach of contemporary facilities. However, a
new, robust X-ray detection of Arcturus would inform the next
generation of high-energy observatories, whether such advanced
measurements in fact would be feasible.

Sequence Number: 402024

Title : Killing two birds in NGC 5907 with one stone: possible dust scattering
halo in ULX1 and the newly discovered ULX2
PI: Pintore
Abstract: NGC 5907 contains two transient ULXs (separated by 28"), with ULX1
being the most extreme ULX pulsar. In the last Chandra observation,
ULX1 was weak (Lx~2e38 erg/s) and surrounded by diffuse X-ray emission
of radius ~3". It could be a scattering halo from dust in NGC 5907 of
the previous ULX1 high state. This can be proved by observing the flux
decrease expected in this case. A negative result is still interesting
since this would be the only ULX with a persistent X-ray nebula. We
discovered ULX2 at a peak luminosity of ~6e39 erg/s, with a multicolor
blackbody disc spectrum, reminiscent of the soft state of Galactic
accreting black holes (BHs). Hence ULX2 may possibly host a 30 Msun BH
accreting at <= Eddington rates. The source is now decaying below the
ULX regime and, if correctly interpreted, we expect a spectral
transition to a hard powerlaw spectral shape. The current state of the
two targets gives the opportunity to achieve both goals with a single
Chandra observation.

Sequence Number: 402024

Title : Killing two birds in NGC 5907 with one stone: possible dust scattering
halo in ULX1 and the newly discovered ULX2
PI: Pintore
Abstract: NGC 5907 contains two transient ULXs (separated by 28"), with ULX1
being the most extreme ULX pulsar. In the last Chandra observation,
ULX1 was weak (Lx~2e38 erg/s) and surrounded by diffuse X-ray emission
of radius ~3". It could be a scattering halo from dust in NGC 5907 of
the previous ULX1 high state. This can be proved by observing the flux
decrease expected in this case. A negative result is still interesting
since this would be the only ULX with a persistent X-ray nebula. We
discovered ULX2 at a peak luminosity of ~6e39 erg/s, with a multicolor
blackbody disc spectrum, reminiscent of the soft state of Galactic
accreting black holes (BHs). Hence ULX2 may possibly host a 30 Msun BH
accreting at <= Eddington rates. The source is now decaying below the
ULX regime and, if correctly interpreted, we expect a spectral
transition to a hard powerlaw spectral shape. The current state of the
two targets gives the opportunity to achieve both goals with a single
Chandra observation.

Sequence Number: 201205

Title : Alpha Centauri: Mind the Gap!
PI: AYRES
Abstract: Cycle 19 proposal to continue long-term monitoring of coronal X-ray
activity cycles of sunlike Alpha Centauri A (G2V) and B (K1V) was not
approved. New Cycle 20 request will address panel's concerns. Even if
Cycle 20 proposal is approved, still will be unpleasant gap in the
semi-annual coverage, ongoing since 2005. Long-term HRC X-ray series
on AlpCen is unique, fundamentally important: key contribution of
Chandra to understanding cycling "Dynamos" of late-type stars, high
scientific priority in solar-stellar physics. Although stellar cycles
are known from CaII monitoring, X-rays contribute uniquely owing to
50X larger contrast at high-energies. A 5 ks pointing in mid-2018
would fill the gap. In fact, most recent AlpCen-A L_X (Ayres: 2018,
RNAAS) shows a possible, unusual, rapid downturn, in the declining
phase of its cycle (previous decline 2001-05 missed by lack of
observations). Only Chandra can resolve AB at present.

Sequence Number: 402022

Title : Measure spin-up of NGC 300 ULX-1
PI: Vasilopoulos
Abstract: NGC 300 ULX-1 is a newly identified ULX pulsar. The system has shown a
extraordinary spin up rate within the last year, when it spun-up from
31 sec to 20 sec. We request 2x10 ks chandra observations separated by
2-4 days in order to accurately measure the spin up rate of the
pulsar.

Sequence Number: 402021

Title : Measure spin-up of NGC 300 ULX-1
PI: Vasilopoulos
Abstract: NGC 300 ULX-1 is a newly identified ULX pulsar. The system has shown a
extraordinary spin up rate within the last year, when it spun-up from
31 sec to 20 sec. We request 2x10 ks chandra observations separated by
2-4 days in order to accurately measure the spin up rate of the
pulsar.

Sequence Number: 402020

Title : GW170817: Tracking the X-ray light curve to study the origin of the
emission
PI: Wilkes
Abstract: Continued tracking of the light curve of this unique NS-NS merger to
understand the emission mechanisms and the structure. We will include
the proposing DDT teams as co-Is on this proposal. They will all have
access to the data, but this proposal does not require that they work
together.

Sequence Number: 402020

Title : GW170817: Tracking the X-ray light curve to study the origin of the
emission
PI: Wilkes
Abstract: Continued tracking of the light curve of this unique NS-NS merger to
understand the emission mechanisms and the structure. We will include
the proposing DDT teams as co-Is on this proposal. They will all have
access to the data, but this proposal does not require that they work
together.

Sequence Number: 402020

Title : GW170817: Tracking the X-ray light curve to study the origin of the
emission
PI: Wilkes
Abstract: Continued tracking of the light curve of this unique NS-NS merger to
understand the emission mechanisms and the structure. We will include
the proposing DDT teams as co-Is on this proposal. They will all have
access to the data, but this proposal does not require that they work
together.

Sequence Number: 402020

Title : GW170817: Tracking the X-ray light curve to study the origin of the
emission
PI: Wilkes
Abstract: Continued tracking of the light curve of this unique NS-NS merger to
understand the emission mechanisms and the structure. We will include
the proposing DDT teams as co-Is on this proposal. They will all have
access to the data, but this proposal does not require that they work
together.

Sequence Number: 402020

Title : GW170817: Tracking the X-ray light curve to study the origin of the
emission
PI: Wilkes
Abstract: Continued tracking of the light curve of this unique NS-NS merger to
understand the emission mechanisms and the structure. We will include
the proposing DDT teams as co-Is on this proposal. They will all have
access to the data, but this proposal does not require that they work
together.

Sequence Number: 402019

Title : Detecting X-ray emission from a very massive black hole binary
PI: Liu
Abstract: Our most recent work with LAMOST spectroscopic survey has revealed a
black hole candidate with a B companion, which can be more massive
than 40 solar masses judging from the relative motion of the B
companion (from its absorption lines, with a radial velocity
semi-amplitude of 50km/s) and the black hole (from its broad strong
Halpha emission line, with a semi-amplitude below 10km/s). About 20
LAMOST low resolution spectra taken in two years have revealed its
binarity with a period of 70 days, and GAIA data also confirms its
binarity independently. We have launched a GTC/OSIRIS campaign to take
20 spectra in two months, and a Keck/HIRESr campaign to take 18
spectra in two months, to fine sample its 70-day period and better
determine the binary properties. . Here we propose a 10ksec Chandra
exposure to detect its X-ray emission.

Sequence Number: 703470

Title : The X-rays of a bright QSO well within the epoch of reionization at
z=7.54
PI: Banados
Abstract: After almost a decade of intense search, our team has finally
discovered a bright QSO well within the epoch of reionization, at
z=7.54. This is by far the most distant QSO known (previous record:
7.08), at a cosmic age of 690 Myr, i.e., only 5% of our universe's
current age. This is the first QSO whose spectrum shows clear evidence
of an intergalactic medium that is >20% neutral and that reionization
is underway. We propose Chandra observations of this unique object to
(i) probe evolution of the X-ray-to-optical luminosity ratio
(alpha-ox) to the highest accessible redshift; (ii) provide a more
reliable estimate of the QSO's bolometric luminosity, and (iii) assess
the feasibility of deeper Chandra and XMM observations for the
upcoming cycles, which would allow us to test whether the first black
holes are accreting at super-Eddington rates.

Sequence Number: 201204

Title : Characterizing X-ray driven molecular chemistry in a young
protoplanetary disk
PI: Cleeves
Abstract: Young (Myr-old) stars are both X-ray luminous and variable.
Surrounding the star is a molecule-rich protoplanetary disk whose
chemistry is expected to evolve slowly, over $\sim0.01-1$ Myr. In this
context, ALMA provided a curious puzzle when we discovered short-term
variability in the H13CO+ J=3-2 line across three observations of a
disk taken over just a single year (Cleeves et al. 2017). One
explanation is stellar X-ray activity perturbing the chemical steady
state'' of the disk, where HCO+ is a known X-ray sensitive molecule
(Cleeves et al. 2014). We were recently awarded SMA time to test the
X-ray driven variability hypothesis (one observation every 6-7 days
for 2 months) by measuring the magnitude and frequency of H13CO+
variability. We propose here to compliment these SMA observations with
Chandra monitoring to directly connect for the first time the
time-varying X-ray state of the star to the composition of the
planet-forming disk.

Sequence Number: 201203

Title : Characterizing X-ray driven molecular chemistry in a young
protoplanetary disk
PI: Cleeves
Abstract: Young (Myr-old) stars are both X-ray luminous and variable.
Surrounding the star is a molecule-rich protoplanetary disk whose
chemistry is expected to evolve slowly, over $\sim0.01-1$ Myr. In this
context, ALMA provided a curious puzzle when we discovered short-term
variability in the H13CO+ J=3-2 line across three observations of a
disk taken over just a single year (Cleeves et al. 2017). One
explanation is stellar X-ray activity perturbing the chemical steady
state'' of the disk, where HCO+ is a known X-ray sensitive molecule
(Cleeves et al. 2014). We were recently awarded SMA time to test the
X-ray driven variability hypothesis (one observation every 6-7 days
for 2 months) by measuring the magnitude and frequency of H13CO+
variability. We propose here to compliment these SMA observations with
Chandra monitoring to directly connect for the first time the
time-varying X-ray state of the star to the composition of the
planet-forming disk.

Sequence Number: 201202

Title : Characterizing X-ray driven molecular chemistry in a young
protoplanetary disk
PI: Cleeves
Abstract: Young (Myr-old) stars are both X-ray luminous and variable.
Surrounding the star is a molecule-rich protoplanetary disk whose
chemistry is expected to evolve slowly, over $\sim0.01-1$ Myr. In this
context, ALMA provided a curious puzzle when we discovered short-term
variability in the H13CO+ J=3-2 line across three observations of a
disk taken over just a single year (Cleeves et al. 2017). One
explanation is stellar X-ray activity perturbing the chemical steady
state'' of the disk, where HCO+ is a known X-ray sensitive molecule
(Cleeves et al. 2014). We were recently awarded SMA time to test the
X-ray driven variability hypothesis (one observation every 6-7 days
for 2 months) by measuring the magnitude and frequency of H13CO+
variability. We propose here to compliment these SMA observations with
Chandra monitoring to directly connect for the first time the
time-varying X-ray state of the star to the composition of the
planet-forming disk.

Sequence Number: 201201

Title : Characterizing X-ray driven molecular chemistry in a young
protoplanetary disk
PI: Cleeves
Abstract: Young (Myr-old) stars are both X-ray luminous and variable.
Surrounding the star is a molecule-rich protoplanetary disk whose
chemistry is expected to evolve slowly, over $\sim0.01-1$ Myr. In this
context, ALMA provided a curious puzzle when we discovered short-term
variability in the H13CO+ J=3-2 line across three observations of a
disk taken over just a single year (Cleeves et al. 2017). One
explanation is stellar X-ray activity perturbing the chemical steady
state'' of the disk, where HCO+ is a known X-ray sensitive molecule
(Cleeves et al. 2014). We were recently awarded SMA time to test the
X-ray driven variability hypothesis (one observation every 6-7 days
for 2 months) by measuring the magnitude and frequency of H13CO+
variability. We propose here to compliment these SMA observations with
Chandra monitoring to directly connect for the first time the
time-varying X-ray state of the star to the composition of the
planet-forming disk.

Sequence Number: 201200

Title : Characterizing X-ray driven molecular chemistry in a young
protoplanetary disk
PI: Cleeves
Abstract: Young (Myr-old) stars are both X-ray luminous and variable.
Surrounding the star is a molecule-rich protoplanetary disk whose
chemistry is expected to evolve slowly, over $\sim0.01-1$ Myr. In this
context, ALMA provided a curious puzzle when we discovered short-term
variability in the H13CO+ J=3-2 line across three observations of a
disk taken over just a single year (Cleeves et al. 2017). One
explanation is stellar X-ray activity perturbing the chemical steady
state'' of the disk, where HCO+ is a known X-ray sensitive molecule
(Cleeves et al. 2014). We were recently awarded SMA time to test the
X-ray driven variability hypothesis (one observation every 6-7 days
for 2 months) by measuring the magnitude and frequency of H13CO+
variability. We propose here to compliment these SMA observations with
Chandra monitoring to directly connect for the first time the
time-varying X-ray state of the star to the composition of the
planet-forming disk.

Sequence Number: 201199

Title : Characterizing X-ray driven molecular chemistry in a young
protoplanetary disk
PI: Cleeves
Abstract: Young (Myr-old) stars are both X-ray luminous and variable.
Surrounding the star is a molecule-rich protoplanetary disk whose
chemistry is expected to evolve slowly, over $\sim0.01-1$ Myr. In this
context, ALMA provided a curious puzzle when we discovered short-term
variability in the H13CO+ J=3-2 line across three observations of a
disk taken over just a single year (Cleeves et al. 2017). One
explanation is stellar X-ray activity perturbing the chemical steady
state'' of the disk, where HCO+ is a known X-ray sensitive molecule
(Cleeves et al. 2014). We were recently awarded SMA time to test the
X-ray driven variability hypothesis (one observation every 6-7 days
for 2 months) by measuring the magnitude and frequency of H13CO+
variability. We propose here to compliment these SMA observations with
Chandra monitoring to directly connect for the first time the
time-varying X-ray state of the star to the composition of the
planet-forming disk.

Sequence Number: 201198

Title : Characterizing X-ray driven molecular chemistry in a young
protoplanetary disk
PI: Cleeves
Abstract: Young (Myr-old) stars are both X-ray luminous and variable.
Surrounding the star is a molecule-rich protoplanetary disk whose
chemistry is expected to evolve slowly, over $\sim0.01-1$ Myr. In this
context, ALMA provided a curious puzzle when we discovered short-term
variability in the H13CO+ J=3-2 line across three observations of a
disk taken over just a single year (Cleeves et al. 2017). One
explanation is stellar X-ray activity perturbing the chemical steady
state'' of the disk, where HCO+ is a known X-ray sensitive molecule
(Cleeves et al. 2014). We were recently awarded SMA time to test the
X-ray driven variability hypothesis (one observation every 6-7 days
for 2 months) by measuring the magnitude and frequency of H13CO+
variability. We propose here to compliment these SMA observations with
Chandra monitoring to directly connect for the first time the
time-varying X-ray state of the star to the composition of the
planet-forming disk.

Sequence Number: 402012

Title : GW170817: Tracking the X-ray light curve to study the origin of the
emission
PI: Wilkes
Abstract: This proposal is a merger of several DDT requests to follow-up the
NS-NS merger: GW170817 as it comes out of sunblock. We will include
the proposing DDT teams as co-Is on this proposal. They will all have
access to the data, but this proposal does not require that they work
together.

Sequence Number: 402012

Title : GW170817: Tracking the X-ray light curve to study the origin of the
emission
PI: Wilkes
Abstract: This proposal is a merger of several DDT requests to follow-up the
NS-NS merger: GW170817 as it comes out of sunblock. We will include
the proposing DDT teams as co-Is on this proposal. They will all have
access to the data, but this proposal does not require that they work
together.

Sequence Number: 402011

Title : Searching for outflows from a nearby super-Eddington accreting neutron
star
PI: Degenaar
Abstract: Swift J0243.6+6124 is a newly discovered Be/X-ray binary that harbours
a 9.8-s pulsar and went into outburst 30 days ago (ATel #10809). It
has been brightening since and reached super-Eddington luminosities on
Nov 1 (Lx~4E38 erg/s), which have been sustained since then (Lx~E39
erg/s on Nov 6). Accretion at super-Eddington rates is predicted to be
associated with strong outflows, both jets and disk winds. Testing
this idea is challenging because super-Eddington accreting neutron
stars are located in other galaxies. However, Swift J0243.6+6124 is
located at a distance of only 4 kpc (Doroshenko et al. 2017,
arXiv:1710.10912). This provides a unique opportunity to study
outflows in the super-Eddington accretion regime. We have secured VLA
radio observations (PI van den Eijnden) to search for a jet. Here, we
request Chandra/HETG observations to look for highly blue-shifted,
ionized absorption features at high (>5 keV) energy that would reveal
a disk wind.

Sequence Number: 801803

Title : The most distant X-ray luminous cluster discovered by ROSAT
PI: Ebeling
Abstract: We propose a short ACIS-I observation of eMACSJ0324, the most distant
massive cluster discovered to date by ROSAT, confirmed in Sep 2017 to
be at z=0.901 (8 redshifts). At 1.4e^45 erg/s (0.1-2.4 keV), our
target is as X-ray luminous as the giant galaxy clusters (and HFF
targets) MACSJ0416, MACSJ1149, or MACSJ0717 - but at twice the
redshift. If eMACSJ0324 is confirmed to be as massive as its more
nearby, famous siblings (its present X-ray luminosity estimate is
based on 10 RASS photons), it would be one of fewer than a handful
exceptionally massive clusters known at z~1, the first extreme mass
concentrations (>1e^15 M_sun) to decouple from the Hubble flow. Our
DDT request, complemented by an HST Cycle 25 Mid-Cycle proposal, aims
to use Chandra's unparalleled resolution to constrain the contribution
from any point sources to the X-ray flux of eMACSJ0324 as observed in
the RASS, and to obtain a robust measurement of the cluster's total
X-ray luminosity from about 1500 net photons.

Sequence Number: 100171

Title : Uranus During an Interplanetary Coronal Mass Ejection
PI: Dunn
Abstract: While Jupiter's X-ray Aurora was first detected by the Einstein
Observatory, it remains unknown what processes allow it to create the
energies required for soft X-ray Aurorae. Saturn does not produce
detectable X-ray Aurora. Why these 2 rapidly rotating giant planets,
with internal plasma sources, have such different auroral intensities
remains unclear. Saturn's magnetic field is parallel to its rotation
axis, but Jupiter's has a 10-degree tilt, which helps produce large
electric fields. Uranus' magnetic field is at 60 degrees to the
rotation axis, producing ever-varying magnetospheric dynamics and
reconnection. Given that reconnection is the common explanation for
Jupiter's X-ray Aurora, the extent/absence of X-ray Aurora at Uranus
would show the importance of reconnection as a driver. On 10 Nov, an
ICME arrives at Uranus, which will compress the magnetosphere,
increasing reconnection rates. At Jupiter, ICMEs increase X-ray
auroral counts by a factor of 3-6, improving detectability.

Sequence Number: 100171

Title : Uranus During an Interplanetary Coronal Mass Ejection
PI: Dunn
Abstract: While Jupiter's X-ray Aurora was first detected by the Einstein
Observatory, it remains unknown what processes allow it to create the
energies required for soft X-ray Aurorae. Saturn does not produce
detectable X-ray Aurora. Why these 2 rapidly rotating giant planets,
with internal plasma sources, have such different auroral intensities
remains unclear. Saturn's magnetic field is parallel to its rotation
axis, but Jupiter's has a 10-degree tilt, which helps produce large
electric fields. Uranus' magnetic field is at 60 degrees to the
rotation axis, producing ever-varying magnetospheric dynamics and
reconnection. Given that reconnection is the common explanation for
Jupiter's X-ray Aurora, the extent/absence of X-ray Aurora at Uranus
would show the importance of reconnection as a driver. On 10 Nov, an
ICME arrives at Uranus, which will compress the magnetosphere,
increasing reconnection rates. At Jupiter, ICMEs increase X-ray
auroral counts by a factor of 3-6, improving detectability.

Sequence Number: 201197

Title : Candidate TDE AT 2017gbl
PI: Heikkila
Abstract: We discovered a very likely Tidal Disruption Event (TDE) AT 2017gbl in
the luminous infrared galaxy (LIRG) IRAS 23436+5257 (ATels 10651,
10712), which are very rare events. The recent discovery of another
TDE candidate in the LIRG F01004-2237 suggests that there is an
enhanced rate of TDEs in LIRGs which would often be missed due to the
large amounts of gas and dust. TDEs can also be extremely bright in
X-rays. We observed AT 2017gbl with Swift, with no source detected and
with upper limit ~4*10^41 erg/s. LIRGs also host a population of X-ray
binaries, and the X-ray luminosity from the host can be estimated from
the IR-luminosity, at least ~ 5*10^40 erg/s in the case of IRAS
23436+5257. By observing down to this limit, we will put strict
constrains on the intrinsic luminosity of the transient, determining
its nature. In addition, this would be the first direct X-ray
detection of IRAS 23436+5257 and important eg. for studying the
SFR-X-ray luminosity relationship in distant LIRGs.

Sequence Number: 402010

Title : Probing the Low State of the Most Extreme ULX Pulsar
PI: belfiore
Abstract: The 3 Ultraluminous X-ray Sources (ULXs) driven by accreting neutron
stars well beyond their Eddington limit (L(Edd)) deserve more
investigation as they constrain accretion in a regime that eludes
simple explanations. They all display superorbital flux modulations
and rarely enter a low state not yet understood, that could shed light
on their physics. The sources could go sub-Eddington, or the
centrifugal push could inhibit accretion (propeller effect), or the
pulsar could be obscured by optically thick material (in a disk or
winds). The most extreme ULX pulsar is NGC 5907 ULX (Israel et al
2017, I17), at 500 times L(Edd). Current observational campaigns with
Swift, XMM-Newton, and NuSTAR have recently seen it entering a low
state (<20 L(Edd)) and no recovery after one superorbital period. Now
only Chandra can probe its low flux, resolving it from other sources
in its galaxy (I17, fig S1; Walton et al 2015), and distinguish a
propeller state (~2 L(Edd)) from other scenarios.

Sequence Number: 503034

Title : X-ray monitoring of GRB170817A
PI: Troja
Abstract: GRB170817A is an under-luminous short GRB possibly located at 40 Mpc
and associated to the peculiar infrared/optical transient SSS17a. Deep
upper limits constrain the presence of an on-axis afterglow. Here we
propose to search for X-ray emission at late times in order to
constrain the presence of an off-axis afterglow and isotropic
electromagnetic counterparts. Due to the proximity to another X-ray
source and the expected faintness of the afterglow fluxes, only the
accuracy and sensitivity of Chandra will allow us to detect the X-ray
counterpart.

Sequence Number: 300403

Title : The late outburst evolution of Nova Lup 2016: a likely solution of
nova 'mysteries'
PI: Orio
Abstract: The decline of Nova Lup 2016 in the supersoft X-ray phase is occurring
more slowly than in most novae, allowing scheduling during a poorly
known phase, important for the models. The nova has been observed at
maximum with XMM and the PI has kindly shared his data; it is now
monitored with Swift. A Chandra LETG exposure would allow: 1) Precise
determination of N(H), differentiating between cooling and spectral
softening due to diminishing intrinsic absorption; 2) Witnessing
whether turn-off is occurring with decreasing flux at almost constant
T(eff) (implying a shrinking, but still hot surface region), as
inferred in some magnetic novae at the beginning of the decline or in
the early quiescence, or whether the WD is isotropically cooling; 3)
Observing whether the residual wind from the compact WD ceases before
the burning is turned off; 4) Measuring absorption and emission lines
due to transitions of intermediate mass ions, constraining chemical
evolution.

Sequence Number: 703616

Title : Deep X-ray follow-up of a TDE candidate
PI: Nicholl
Abstract: The transient PS17dhz shows optical signatures typical of tidal
disruption events (TDEs), including blackbody temperature >30000 K and
broad He II emission. However, the host is unusual: a compact galaxy
with absolute magnitude M_r ~ -18, suggesting that PS17dhz may have a
smaller black hole mass than other TDEs. From Swift data we have found
an optical flux F_opt ~ 10^-13 erg/s/cm2, and an X-ray limit F_X <
10^-13 erg/s/cm2. All optical TDEs with X-ray detections have had
X-ray to optical ratios >~ 1, suggesting that PS17dhz is X-ray faint.
However, there are UV/optical TDEs without X-ray detections ( veiled
TDEs). The lack of X-rays could be due to additional
reprocessing/obscuration around the black hole. The Swift
non-detection suggests that PS17dhz is veiled, but since the Swift
X-ray limit is already close to L_opt, a deeper observation with
Chandra gives one of the best chances to detect weak X-rays from a
veiled TDE.

Sequence Number: 503033

Title : Precise localization of the ultra long high-energy transient
GRB170714A
PI: Troja
Abstract: GRB170714A is a peculiar high-energy transient of ultra-long (>1,000
s) duration. Its nature is still unclear: its high-energy properties
suggest that it could be a relativistic tidal disruption event or a
rare ultralong GRB, produced by an exotic stellar progenitor. Further
multi-wavelength observations are critical to characterize the
explosion properties and its host environment. Tentative optical and
radio counterparts were reported in the literature. However, their
positions differ significantly and might be contaminated by other,
unrelated sources. Chandra observations are critical to improve the
positional accuracy of the X-ray transient, to precisely determine its
position with respect to the underlying host galaxy, and to determine
its association with the putative counterparts.

Sequence Number: 703470

Title : The X-rays of a bright QSO well within the epoch of reionization at
z=7.54
PI: Banados
Abstract: After almost a decade of intense search, our team has finally
discovered a bright QSO well within the epoch of reionization, at
z=7.54. This is by far the most distant QSO known (previous record:
7.08), at a cosmic age of 690 Myr, i.e., only 5% of our universe's
current age. This is the first QSO whose spectrum shows clear evidence
of an intergalactic medium that is >20% neutral and that reionization
is underway. We propose Chandra observations of this unique object to
(i) probe evolution of the X-ray-to-optical luminosity ratio
(alpha-ox) to the highest accessible redshift; (ii) provide a more
reliable estimate of the QSO's bolometric luminosity, and (iii) assess
the feasibility of deeper Chandra and XMM observations for the
upcoming cycles, which would allow us to test whether the first black
holes are accreting at super-Eddington rates.

Sequence Number: 703469

Title : X-ray confirmation of two intermediate mass black hole candidates
PI: Chilingarian
Abstract: For the last two decades, the international research community has
been hunting the elusive population of intermediate mass black holes
(IMBHs) crucially important for the understanding of galaxy and BH
co-evolution. Despite several good candidates have been found with
various techniques, it is still unclear whether IMBHs existed in the
early Universe and if there is a common way for them to remain intact
as a population till our epoch. We have performed a comprehensive IMBH
search in nearby galaxy nuclei using their optical spectral signatures
(broad Halpha+BPT diagram) combined with advanced data mining in the
Virtual Observatory and identified ~300 candidates with MBH<2e5 Msun,
which pose as low-luminosity active galactic nuclei. The X-ray
detection would confirm their AGN nature and secure the IMBH
classification. We propose to observe 2 IMBH candidates with Chandra
as a pilot project: it will validate our search technique and allow us
to claim the discovery of the IMBH population

Sequence Number: 703468

Title : X-ray confirmation of two intermediate mass black hole candidates
PI: Chilingarian
Abstract: For the last two decades, the international research community has
been hunting the elusive population of intermediate mass black holes
(IMBHs) crucially important for the understanding of galaxy and BH
co-evolution. Despite several good candidates have been found with
various techniques, it is still unclear whether IMBHs existed in the
early Universe and if there is a common way for them to remain intact
as a population till our epoch. We have performed a comprehensive IMBH
search in nearby galaxy nuclei using their optical spectral signatures
(broad Halpha+BPT diagram) combined with advanced data mining in the
Virtual Observatory and identified ~300 candidates with MBH<2e5 Msun,
which pose as low-luminosity active galactic nuclei. The X-ray
detection would confirm their AGN nature and secure the IMBH
classification. We propose to observe 2 IMBH candidates with Chandra
as a pilot project: it will validate our search technique and allow us
to claim the discovery of the IMBH population

Sequence Number: 401894

Title : The longest AMXP outburst: looking for pulsation in MAXI J0911-655
after 450 days
PI: Riggio
Abstract: MAXI J0911-655 (J0911) is a new rare accreting millisecond X-ray
pulsar (AMXPs), spinning at ~340 Hz in NGC 2808. Since the latest XMM
observation, the source has been monitored by Swift and INTEGRAL (ATel
#10425). Astonishingly, the source proved to be still in outburst
after more than 450 days. This is by far a record for an AMXP, whose
outburst usually last 2-3 weeks. Standing the current flux of the
source, we propose a 30 ks Chandra HRC-S timing mode DDT ToO aiming to
i) detect the pulsation, ii) obtain a precise spin frequency value to
obtain, for the first time, a direct measurement of the spin frequency
variation (expected to be ~1e-5Hz) during the same outburst, iii)
improve orbital parameters. Those information have strong scientific
return, because the presence of the pulsation will settle the still
debated model of the magnetic field burial under accretion, and the
measurement of nudot will permit to test the accretion mechanism and
the role in it of the magnetic field.

Sequence Number: 401893

Title : Testing a BeX origin for
PI: Maccarone
Abstract: We would like to extend the exposure time on Chakrabarty's TOO on this
source to 8 ksec. Our goal is to search for pulsations from the
source. It has a position consistent with a blue star with Galactic
reddening and an infrared excess in H band as seen by 2MASS. It also
shows a spectrum with Gamma=0.5+-0.5, which is typical for accreting
high-B field pulsars, but uncommon for low mass X-ray binary
transients. If confirmed, the source would be an X-ray pulsar at 25
kpc, which can be followed up optically. It gives us a start on
understanding the transient populations of the far side of the Galaxy
AND of the outer Galaxy. 8 ksec would allow for a 5 sigma detection of
the pulsation, even in the event of a fading by a factor of a few of
the source, and will give at least 5 cycles for any Be X-ray binary
pulse period.

Sequence Number: 502973

Title : X-rays as a probe of the progenitor of the Type Ia SN2017cbv
PI: Drout
Abstract: SN2017cbv is a nearby, bright, and young Type Ia SN that was recently
discovered in NGC 5643 (d~15 Mpc) within hours of explosion. Despite
their importance for Cosmology, questions still remain regarding the
nature and diversity of the progenitors that give rise to Type Ia SN.
Progress can be made by obtaining deep X-ray observations---which
probe the density of the CSM shaped by the progenitor system---for SN
which also have tight constraints on their final progenitor
configuration from early (1-2 day) optical/UV light curves. SN2017cbv
represents a rare opportunity when both sets of constraints are
possible. By timing X-ray observations with optical peak, we can probe
densities as low as a few d-9 Msun/yr, enabling us to distinguish
between many giant, main sequence, and double-degenerate progenitors.
SN2017cbv would represent only the third Type Ia SN for which such
deep limits are possible and this study may lead to the first
detection of X-ray radiation from a Type Ia SN.

Sequence Number: 401892

Title : Puzzling clump with 'whiskers' ejected from a binary
PI: Pavlov
Abstract: Three ACIS-I observations of 2011-2014 allowed us to discover an
extended object moving southwest from the famous high-mass gamma-ray
binary PSR B1259-63/LS 2883 with a surprisingly high velocity, ~0.06c,
perhaps even with acceleration. Such a phenomenon had never been
observed previously. We interpreted it as a clump of stellar matter
ejected from the disk around the massive star near binary periastron
and accelerated and illuminated by the unshocked pulsar wind. The
clump disappeared by 2015 Apr, but a new one was seen emerging from
the binary in 2016 Jan. The latest observation of 2017 Jan 6 showed
the new clump had moved southwest, but its morphology was very
unusual. Most notably, the elongated clump was crossed by narrow
"whiskers" perpendicular to the direction of motion. In addition, a
new extended feature was seen emerging northward from the binary. To
study the evolution of these unexpected features, we request a DDT
observation in April 2017.

Sequence Number: 703466

Title : M87 with Chandra and the Event Horizon Telescope
PI: Neilsen
Abstract: X-ray observations of accreting black holes are ideal for probing the
physical plasma processes close to the event horizon, which can
include both jet formation and magnetic reconnection leading to flares
and variability. Our ability to study these processes is about to take
a major step forward with the Event Horizon Telescope. During the
period April 5-April 14, the EHT will be online with ALMA and 7 other
stations around the world, and its observations of Sgr A* and M87 may
be the first set of observations capable of resolving the shadow of
these important supermassive black holes. But the ability to interpret
EHT data relies on a proper understanding of the plasma processes and
accretion structure around the black hole, as provided by Chandra. We
have arranged coordinated Sgr A* time; here we are requesting Chandra
time on M87 to probe variability and spectra of the accretion flow and
the jet knot HST-1.

Sequence Number: 703466

Title : M87 with Chandra and the Event Horizon Telescope
PI: Neilsen
Abstract: X-ray observations of accreting black holes are ideal for probing the
physical plasma processes close to the event horizon, which can
include both jet formation and magnetic reconnection leading to flares
and variability. Our ability to study these processes is about to take
a major step forward with the Event Horizon Telescope. During the
period April 5-April 14, the EHT will be online with ALMA and 7 other
stations around the world, and its observations of Sgr A* and M87 may
be the first set of observations capable of resolving the shadow of
these important supermassive black holes. But the ability to interpret
EHT data relies on a proper understanding of the plasma processes and
accretion structure around the black hole, as provided by Chandra. We
have arranged coordinated Sgr A* time; here we are requesting Chandra
time on M87 to probe variability and spectra of the accretion flow and
the jet knot HST-1.

Sequence Number: 703465

Title : X-ray flux of the Narrow-Line Seyfert 1 galaxy WPVS 007 during a high
UV flux state
PI: Grupe
Abstract: We request a short, 10ks, observation with Chandra ACIS-S of the
highly X-ray variable Narrow Line Seyfert 1 Galaxy WPVS 007
quasi-simultaneously with HST between March 13 and 26. WPVS 007 is one
of the most unusual AGN showing strong variabilty in broad absorption
lines - a feature that is only seen in high-luminous quasars. We have
monitored WPVS 007 since October 2005 with Swift, but we can typically
not detect it in X-rays. Our last observation of WPVS 007 by Chandra
in March 2015 when it was fount to be in an extremely low UV flux
state (Leighgly et al. 2015) found it at a level of 8e-4 counts/s in
ACIS-s corresponding to a flux in the 0.3-10 keV band of 1e-17 W/m2.
Merging all Swift observaton since then (66ks) results in an 3sigma ul
of 1.4e-17 W/m2. Obtaining a Chandra observation close to the HST
observation will provide us with a crucial flux measurement that will
allow us to determine the intrinsic luminosity of the AGN. Note,
WPVS007 is currently at a bright UV state.

Sequence Number: 401891

Title : A Hig-Resolution Spectrum of the Black Hole GRS 1716-249
PI: Miller
Abstract: This black hole has been in outburst for several weeks, but it has
only recently become visible with the Swift/XRT and Chandra. The
strong outburst (0.2-0.3 Crab) has been visible with the BAT. On
January 27, we requested a Swift DDT of the source, and the resulting
spectrum is strongly encouraging. The source shows a strong, broad
iron line in just a 1 ks exposure, potentially with wind absorption
lines imprinted as well. We are currently attempting to expand the
number of black holes with spin measurements, and to better understand
the duty cycles of outflows. The XRT exposure gives a flux of 6 E-9
erg/cm2/s in the 0.7-10 keV band. Experience suggests that a 30 ks
HETG spectrum of a source at this flux level will yield a sensitive
Chandra spectrum. A spectrum has been sent to the Director.

Sequence Number: 100168

Title : Observing Jupiter's X-ray aurora during Juno apojove
PI: Jackman
Abstract: We don't know what causes Jupiter's auroral X-ray emission. Several
drivers (reconnection, Kelvin Helmholtz) have been suggested but all
require testing of local magnetic field and plasma to uniquely
constrain the source region of particles which cause the emission. The
Juno spacecraft at Jupiter has recently had a trajectory change and
will soon explore a previously unplanned region on the dawn flank near
the statistical position of the magnetopause boundary. We have
agreement to use in situ Juno data to complement X-ray observations.
We propose to observe during 3 apojoves, when Juno is furthest from
Jupiter. Depending on local solar wind conditions Juno will either
sample the solar wind, magnetosheath, or boundary layer inside the
magnetopause. Multiple observations will allow us to test X-ray
generation mechanisms under a range of external conditions. No other
mission of this type is planned in our lifetime and these orbits are
our only chance to sample this magnetospheric region.

Sequence Number: 100167

Title : Observing Jupiter's X-ray aurora during Juno apojove
PI: Jackman
Abstract: We don't know what causes Jupiter's auroral X-ray emission. Several
drivers (reconnection, Kelvin Helmholtz) have been suggested but all
require testing of local magnetic field and plasma to uniquely
constrain the source region of particles which cause the emission. The
Juno spacecraft at Jupiter has recently had a trajectory change and
will soon explore a previously unplanned region on the dawn flank near
the statistical position of the magnetopause boundary. We have
agreement to use in situ Juno data to complement X-ray observations.
We propose to observe during 3 apojoves, when Juno is furthest from
Jupiter. Depending on local solar wind conditions Juno will either
sample the solar wind, magnetosheath, or boundary layer inside the
magnetopause. Multiple observations will allow us to test X-ray
generation mechanisms under a range of external conditions. No other
mission of this type is planned in our lifetime and these orbits are
our only chance to sample this magnetospheric region.

Sequence Number: 100166

Title : Observing Jupiter's X-ray aurora during Juno apojove
PI: Jackman
Abstract: We don't know what causes Jupiter's auroral X-ray emission. Several
drivers (reconnection, Kelvin Helmholtz) have been suggested but all
require testing of local magnetic field and plasma to uniquely
constrain the source region of particles which cause the emission. The
Juno spacecraft at Jupiter has recently had a trajectory change and
will soon explore a previously unplanned region on the dawn flank near
the statistical position of the magnetopause boundary. We have
agreement to use in situ Juno data to complement X-ray observations.
We propose to observe during 3 apojoves, when Juno is furthest from
Jupiter. Depending on local solar wind conditions Juno will either
sample the solar wind, magnetosheath, or boundary layer inside the
magnetopause. Multiple observations will allow us to test X-ray
generation mechanisms under a range of external conditions. No other
mission of this type is planned in our lifetime and these orbits are
our only chance to sample this magnetospheric region.

Sequence Number: 502972

Title : iPTF17cw: A relativistic broad-lined type Ic supernova discovered by
iPTF
PI: Corsi
Abstract: Broad-lined supernovae of type Ic (BL-Ic SNe) are a rare form of
massive star core collapse. The link between BL-Ic SNe and gamma-ray
bursts (GRBs) was first made for GRB980425/SN1998bw, which showed
strong radio emission indicative of relativistic expansion. With SN
2009bb, we have learned that some BL-Ic SNe have relativistic ejecta,
but no associated gamma-rays. These "engine-driven" explosions are
extremely rare (one per 5-10 years), and represent the missing link
between ordinary (non-relativistic) BL-Ic SNe and GRBs. iPTF17cw is a
BL-Ic SN discovered by iPTF on 07 Jan 2017, while following-up LIGO
trigger G268556. Regardless of its association with the LIGO trigger,
our VLA radio observations show that this is a rare relativistic
(v~0.8c) BL-Ic SN. We ask for X-ray observations to constrain: (i)
emission mechanism (IC vs synchrotron) and (ii) synchrotron cooling
freq. (which, combined with radio observations, can constrain magnetic
field and ambient density).

Sequence Number: 703464

Title : Testing a new method for the identification of dual AGN
PI: Secrest
Abstract: Since most galaxies contain massive black holes, and mergers trigger
nuclear accretion, the hierarchical model of galaxy formation predicts
the existence of binary active galactic nuclei (AGN). Confirmed cases
of dual AGN are rare, with efforts for systematic identification
delivering a low yield of confirmed binaries. However, recent
observational and theoretical work has given a new clue in the hunt
for dual AGN: they may preferentially occur in galaxies with very red
mid-IR colors. We have cross-matched the WISE catalog with the 1300
galaxies in the SDSS MaNGA data release. We find a single galaxy with
sufficiently red WISE color (W1-W2=0.84) to classify it as an AGN. Not
only is the host galaxy clearly a spectacular late stage merger, but
the MaNGA IFU data show that the 2 stellar nuclei (separated by ~7
kpc) have optical emission lines consistent with AGN. However, X-ray
observations are required to confirm 2 separate AGN, rather than
extended radiation from a single source.

Sequence Number: 502971

Title : First Deep X-ray Observations of a Rapid, Luminous and Blue Stellar
Explosion
PI: MARGUTTI
Abstract: We propose the first deep X-ray observations of a rapidly-evolving,
luminous, blue stellar explosion. The new class of rapidly-evolving
luminous transients shows luminosities and time scales of evolution
that challenge the traditional Supernovae (SNe) models. Alternative
scenarios include a failed SN of a stripped star, the detonation of a
helium shell on a white dwarf and a SN shock breaking out from a dense
circumstellar medium. To date, due to their large distances (d>500
Mpc), rapidly evolving luminous transients have only been studied in
the optical/UV regime, which is of thermal origin and it is not
sensitive to the nature of the underlying energy source and properties
of the explosion's fastest ejecta. Here we propose to capitalize on
the unique opportunity to study a recently-discovered, nearby (d=150
Mpc), fast-evolving, luminous transient with Chandra to constrain the
environment and explosion properties of this new class of stellar
explosions for the first time.

Sequence Number: 502970

Title : First Deep X-ray Observations of a Rapid, Luminous and Blue Stellar
Explosion
PI: MARGUTTI
Abstract: We propose the first deep X-ray observations of a rapidly-evolving,
luminous, blue stellar explosion. The new class of rapidly-evolving
luminous transients shows luminosities and time scales of evolution
that challenge the traditional Supernovae (SNe) models. Alternative
scenarios include a failed SN of a stripped star, the detonation of a
helium shell on a white dwarf and a SN shock breaking out from a dense
circumstellar medium. To date, due to their large distances (d>500
Mpc), rapidly evolving luminous transients have only been studied in
the optical/UV regime, which is of thermal origin and it is not
sensitive to the nature of the underlying energy source and properties
of the explosion's fastest ejecta. Here we propose to capitalize on
the unique opportunity to study a recently-discovered, nearby (d=150
Mpc), fast-evolving, luminous transient with Chandra to constrain the
environment and explosion properties of this new class of stellar
explosions for the first time.

Sequence Number: 502969

Title : First Deep X-ray Observations of a Rapid, Luminous and Blue Stellar
Explosion
PI: MARGUTTI
Abstract: We propose the first deep X-ray observations of a rapidly-evolving,
luminous, blue stellar explosion. The new class of rapidly-evolving
luminous transients shows luminosities and time scales of evolution
that challenge the traditional Supernovae (SNe) models. Alternative
scenarios include a failed SN of a stripped star, the detonation of a
helium shell on a white dwarf and a SN shock breaking out from a dense
circumstellar medium. To date, due to their large distances (d>500
Mpc), rapidly evolving luminous transients have only been studied in
the optical/UV regime, which is of thermal origin and it is not
sensitive to the nature of the underlying energy source and properties
of the explosion's fastest ejecta. Here we propose to capitalize on
the unique opportunity to study a recently-discovered, nearby (d=150
Mpc), fast-evolving, luminous transient with Chandra to constrain the
environment and explosion properties of this new class of stellar
explosions for the first time.

Sequence Number: 300401

Title : An X-ray spectrum of a transient supersoft source in the Small
Magellanic Cloud
PI: Maccarone
Abstract: This is a transient supersoft source shown in ATel 9866, where we
found an unabsorbed flux of about 2e-11 in the SMC, with a temperature
of about 80 eV. This object was not in ROSAT, and was also observed by
Swift in response to an optical transient from ASSASN (ATel 9859). The
optical light curves clearly show no nova took place, but we now see a
new supersoft source. It is the first strong case for a supersoft
transient which is not a post-nova. How steady burning starts without
a nova is a mystery, but it may also be a key to understanding the
supersoft sources which are one of the proposed Type Ia supernova
channels. Understanding whether the system has emission lines, pure
continuum, or absorption lines, and which lines it has will determine
whether it really is a supersoft source. Exposure is based on trying
to detect the NVII absorption line at 24.78 Ang expected for a hot WD
(Rauch+ 2010). Tommy Nelson simulated and found a clear detection
requires 50 ksec.

Sequence Number: 401890

Title : Probing disk wind and other properties of 4U 1630-47
PI: Bhattacharyya
Abstract: The accreting Galactic black hole transient 4U 1630-47, which is
currently in outburst, is an ideal source to probe two types of
accreted matter ejection: (1) via disk wind and (2) via jet, both
using the observed narrow spectral lines (Diaz Trigo et al., 2013,
Nature, 504, 206; Neilsen et al. 2014; Diaz Trigo et al. 2014).
Chandra gratings are ideal to study such lines. The source also showed
indications of high-frequency (HF) quasi-periodic oscillations (QPOs)
in a rather high (150-450 Hz) frequency range, which can be extremely
useful to probe the strong gravity regime. The AstroSat satellite,
because of its large area and high timing resolution in a broad energy
band, can potentially detect and measure HF QPOs and probe the source
broadband spectrum and state. Hence, our proposed 30 ks Chandra
exposure, nearly contemporaneous with complementary AstroSat
observations, will provide an excellent way to probe the accretion and
ejection mechanism in the strong gravity regime.

Sequence Number: 401889

Title : Constraining the mass of an IMBH candidate in NGC 3310
PI: Earnshaw
Abstract: While much sought-after, intermediate-mass black holes (IMBHs) have so
far remained elusive. Ultraluminous X-ray sources (ULXs) are a good
place to look for IMBHs, and if one appears in the low/hard state we
would expect it to exhibit steady radio jets. A simultaneous
X-ray/radio observation of such an object would allow use of the
fundamental plane (e.g. Merloni et al., 2003) to measure its mass and
confirm its IMBH status. This method has been successfully used before
to identify NGC 2276-3c as a 5e4 solar mass IMBH in Mezcua et al.
(2015). We have found a radio source in NGC 3310 which coincides with
3 ULXs resolved by Chandra, none of which can be identified as the
X-ray counterpart using current radio data. We have been awarded
EVN/e-MERLIN time to attempt to detect and resolve the radio core,
therefore we request quasi-simultaneous observations of this source to
match the radio source with an X-ray source and provide the X-ray
luminosity from which we can calculate the BH mass.

Sequence Number: 201154

Title : Proxima Cen's Stellar Cycle
PI: Wargelin
Abstract: Based on 15 years of optical monitoring, 4 years of Swift X-ray/UV
data, and 2 HRC observations we find evidence for a 7-yr stellar cycle
in Proxima Cen (dMe5.5), a fully convective star. A stellar cycle is
very exciting because most models of stellar magnetic activity predict
such stars cannot support solar-like cycles. Understanding the
structure and evolution of Proxima's magnetic field is also important
because that's what drives X-ray/UV emission and the stellar wind,
which are important factors in modeling the atmosphere (atmospheric
stripping) and habitability of its newly discovered exoplanet. And as
noted by the discovery announcement, "The robust detection of Proxima
b has only been possible after reaching a detailed understanding of
how the star changes on timescales from minutes to a decade." Further
X-ray measurements are required now, while the cycle appears to be at
a maximum, for confirmaton and to better characterize Proxima's
activity over time.

Sequence Number: 201153

Title : Proxima Cen's Stellar Cycle
PI: Wargelin
Abstract: Based on 15 years of optical monitoring, 4 years of Swift X-ray/UV
data, and 2 HRC observations we find evidence for a 7-yr stellar cycle
in Proxima Cen (dMe5.5), a fully convective star. A stellar cycle is
very exciting because most models of stellar magnetic activity predict
such stars cannot support solar-like cycles. Understanding the
structure and evolution of Proxima's magnetic field is also important
because that's what drives X-ray/UV emission and the stellar wind,
which are important factors in modeling the atmosphere (atmospheric
stripping) and habitability of its newly discovered exoplanet. And as
noted by the discovery announcement, "The robust detection of Proxima
b has only been possible after reaching a detailed understanding of
how the star changes on timescales from minutes to a decade." Further
X-ray measurements are required now, while the cycle appears to be at
a maximum, for confirmaton and to better characterize Proxima's
activity over time.

Sequence Number: 201152

Title : Proxima Cen's Stellar Cycle
PI: Wargelin
Abstract: Based on 15 years of optical monitoring, 4 years of Swift X-ray/UV
data, and 2 HRC observations we find evidence for a 7-yr stellar cycle
in Proxima Cen (dMe5.5), a fully convective star. A stellar cycle is
very exciting because most models of stellar magnetic activity predict
such stars cannot support solar-like cycles. Understanding the
structure and evolution of Proxima's magnetic field is also important
because that's what drives X-ray/UV emission and the stellar wind,
which are important factors in modeling the atmosphere (atmospheric
stripping) and habitability of its newly discovered exoplanet. And as
noted by the discovery announcement, "The robust detection of Proxima
b has only been possible after reaching a detailed understanding of
how the star changes on timescales from minutes to a decade." Further
X-ray measurements are required now, while the cycle appears to be at
a maximum, for confirmaton and to better characterize Proxima's
activity over time.

Sequence Number: 201151

Title : Proxima Cen's Stellar Cycle
PI: Wargelin
Abstract: Based on 15 years of optical monitoring, 4 years of Swift X-ray/UV
data, and 2 HRC observations we find evidence for a 7-yr stellar cycle
in Proxima Cen (dMe5.5), a fully convective star. A stellar cycle is
very exciting because most models of stellar magnetic activity predict
such stars cannot support solar-like cycles. Understanding the
structure and evolution of Proxima's magnetic field is also important
because that's what drives X-ray/UV emission and the stellar wind,
which are important factors in modeling the atmosphere (atmospheric
stripping) and habitability of its newly discovered exoplanet. And as
noted by the discovery announcement, "The robust detection of Proxima
b has only been possible after reaching a detailed understanding of
how the star changes on timescales from minutes to a decade." Further
X-ray measurements are required now, while the cycle appears to be at
a maximum, for confirmaton and to better characterize Proxima's
activity over time.

Sequence Number: 401888

Title : Chandra Spectroscopy of SMC X-3 in Outburst
PI: Coe
Abstract: SMC X-3 is an HMXB and pulsar in the SMC. It is currently in the midst
of an apparently super-Eddington outburst (10^39 erg/s, or about 10x
Eddington for a neutron star). This is the brightest outburst from
50-60 sources traced by Coe et al. over a decade, and a special
opportunity. The predicted HETGS count rates will give sensitive
spectra. Lines from the massive companion wind are anticipated; if the
source is truly super-Eddington very strong outflows should also be
detected since radiation and gas will be strongly coupled. Simulated
40 ks spectra based on recent XRT observations, including plasma
components, predict 3-5 sigma line detections in the HETGS band.
Stronger detections are expected if a super-Eddington outflow is
present. Recent work on ULXs shows that at least one such source is a
super-Eddington neutron star. SMC X-3 is much closer and may offer
insights into the accretion flow geometry and physical processes in
this rare accretion phase.

Sequence Number: 401888

Title : Chandra Spectroscopy of SMC X-3 in Outburst
PI: Coe
Abstract: SMC X-3 is an HMXB and pulsar in the SMC. It is currently in the midst
of an apparently super-Eddington outburst (10^39 erg/s, or about 10x
Eddington for a neutron star). This is the brightest outburst from
50-60 sources traced by Coe et al. over a decade, and a special
opportunity. The predicted HETGS count rates will give sensitive
spectra. Lines from the massive companion wind are anticipated; if the
source is truly super-Eddington very strong outflows should also be
detected since radiation and gas will be strongly coupled. Simulated
40 ks spectra based on recent XRT observations, including plasma
components, predict 3-5 sigma line detections in the HETGS band.
Stronger detections are expected if a super-Eddington outflow is
present. Recent work on ULXs shows that at least one such source is a
super-Eddington neutron star. SMC X-3 is much closer and may offer
insights into the accretion flow geometry and physical processes in
this rare accretion phase.

Sequence Number: 401881

Title : Revealing the nature of the mysterious new SMC Transient: Swift
J003233.6-7306
PI: Kennea
Abstract: Starting June 8th, 2016, the Swift SMC Survey, AKA S-CUBED (Kennea et
al., ATEL #9299), began a weekly shallow X-ray survey of the SMC to
search for >1% L_Edd X-ray transients. We have discovered a new
puzzling X-ray transient Swift J003233.6-7306, on the western edge of
the SMC. A NuSTAR DDT observation revealed a hard X-ray spectrum
(Gamma = 1.7), canonical for a BH LMXB in the low/hard state, or
possibly Be/X-ray binary (common in the SMC). The Swift position is
not consistent with any optical counterpart, which is puzzling if a
binary, however given the error in the position from Swift (~4") we
cannot rule out nearby stars as the counterpart. We request a short
(1ks) Chandra in order to localize this transient to the at least ~1"
accuracy needed to definitively identify any counterpart in deep
optical data obtained on the field by OGLE. A firm detection or
non-detection in optical, given the low absorption towards the source,
would place strong constraints on the object type.

Sequence Number: 502963

Title : Prompt Chandra observations of PSR J1119-6127 and its compact nebula
following its magnetar-like burst
PI: Blumer
Abstract: PSR J1119-6127 is a high-magnetic (B) field pulsar with spin
properties (P=408 ms, age=1.7 kyr, B=4.1e13 G) similar to those of
J1846-0258, the first high-B pulsar to show magnetar-like behavior and
one of a handful for which a braking index has been measured
(n=2.91+/-0.05). Chandra studies of J1119-6127 allowed the first
detection of the X-ray counterpart and revealed the evidence for a
compact and faint pulsar wind nebula (PWN; Gonzalez & Safi-Harb 2003
ApJ, 591, 143). A follow up study found evidence for an elongated jet
to the south, and resolved the PSR spectrum from its compact PWN
spectrum for the first time (Safi-Harb & Kumar, 2008, ApJ, 684, 532).
J1119-6127 is considered as a key source in our understanding of the
physical characteristics and processes that differentiate radio
pulsars from magnetars. Just like J1846-0258 , it was predicted that
J1119-6127 will one day reveal itself as a magnetar after an
occasional burst driven by its high B-field.

Sequence Number: 300392

Title : Down with the King: FO Aqr in an Extended Low State
PI: Kennedy
Abstract: FO Aquarii, the so called king of the intermediate polars, is in an
unprecedented and prolonged faint state. Normally brighter than V =
14, FO Aqr is currently at V ~15 and was as faint as V~15.7 at the
start of 2016 May. The faint state began at unknown time between 2015
Dec. 18 (V = 13.71, S. Dvorak, AAVSO) and 2016 May 6 (V ~ 15.6, our
measurement). (For more, including the long term light curve, see
http://www.astronomerstelegram.org/?read=9216) Recent optical
observations have also shown the pulsations to now have a period of
around 11.1 mins (http://www3.nd.edu/~clittlef/FOaqr.png), suggesting
the 2 accretion poles are currently visible. This may be due to a
change in the accretion geometry. We wish to investigate changes to
the x-ray flux and spectrum, and whether the x-ray spin period, which
was seen to be 20.9 mins by Evans et al. (2004, MNRAS, 349, 715) using
XMM-Newton, has also changed to the 10 mins seen in the new optical
data.

Sequence Number: 401819

Title : Measuring the spin period of XMMU J004855.5-734946 during a large
outburst
PI: Vasilopoulos
Abstract: Spin periods of Be/X-ray binary (BeXRB) pulsars are important for
probing their formation channels and the connection between orbital
period and pulsar spin in XRBs (Knigge+ 2011). From the 120 BeXRBs in
the SMC only 50% have known spin periods, with the majority of them
measured during outburst with ToOs. From the remaining systems only 6
have a known orbital period. XMMU J004855.5-734946 is a BeXRB in the
SMC (Haberl & Sturm 2016, XMM Lx ~(0.03-1)x10^35 erg/s) with a 36.43d
orbital period (Atel#9198), but with no X-ray pulsations detected so
far. On 06/24 a 37s Swift/XRT observation detected the system at
Lx~10^37 erg/s (Atel#9197) following a marginal detection on 06/16
(Lx<5x10^36 erg/s) confirming the onset of a large outburst. A
follow-up 1ks Swift ToO on 06/29 measures an Lx = 8.3x10^36 erg/s.
This is a unique opportunity to measure the spin period of one of the
few BeXRBs in the SMC with known orbital period but unknown spin
period.

Sequence Number: 502667

Title : SGR 1935+2154 in a very active state
PI: Kouveliotou
Abstract: The magnetar SGR 1935+2154 has been active since the middle of May
2016 emitting several bursts per day that have triggered the
Fermi/GBM. The burst intensities have been gradually increasing and on
June 26, 2016 the source emitted a very bright burst indicating
potential extreme further source activity. The source persistent
emission properties are strongly influenced by such activity, both in
timing and spectra. We request a Chandra DDT observation to study the
change of the persistent source properties, and potentially study
similar properties for serendipitously recorded bursts. In particular,
we note that the currently reported Nh (GCN 15590) its 3 times higher
than the one measured in the past (Israel etal. 2016) which leads us
to believe that the recent burst is accompanied with metal enhanced
outflow.

Sequence Number: 502666

Title : Chandra Observations of the Brightest and Closest H-poor Superluminous
Supernova Gaia16apd
PI: Yan
Abstract: Gaia16apd was first triggered as a 17.3 mag transient (now 16.5mag) on
2016-05-16 by GAIA. The first optical spectrum on 2016-05-20.92 UT
classified it as a H-poor superluminous supernova (SLSN-I) at z=0.102
and absolute magnitude of -21.0 (Atel #9071). This makes Gaia16apd one
of the brightest and the closest SLSNe-I. SWIFT observations on
2016-05-21 revealed an extremely UV bright source, 15.3mag at 2310A.
Gaia16apd has similar apparent brightness as ASASN-15lh, the most
luminous SLSN-I ever discovered. ASASN-15lh has been observed by
Chandra, and was reported with detections. Magnetar models (Metzger et
al. 2014,Fig.12) predicted that SLSNe-I should have X-ray emission
post optical-peak. With the predicted fluxes well within the Chandra
limit in 10ksec, Gaia16apd offers the unique opportunity to constrain
theoretical models. The proposed observation will shed light on the
long standing mystery of what powers the luminous optical emission
from SLSN-I.

Sequence Number: 502665

Title : Chandra Observations of the Brightest and Closest H-poor Superluminous
Supernova Gaia16apd
PI: Yan
Abstract: Gaia16apd was first triggered as a 17.3 mag transient (now 16.5mag) on
2016-05-16 by GAIA. The first optical spectrum on 2016-05-20.92 UT
classified it as a H-poor superluminous supernova (SLSN-I) at z=0.102
and absolute magnitude of -21.0 (Atel #9071). This makes Gaia16apd one
of the brightest and the closest SLSNe-I. SWIFT observations on
2016-05-21 revealed an extremely UV bright source, 15.3mag at 2310A.
Gaia16apd has similar apparent brightness as ASASN-15lh, the most
luminous SLSN-I ever discovered. ASASN-15lh has been observed by
Chandra, and was reported with detections. Magnetar models (Metzger et
al. 2014,Fig.12) predicted that SLSNe-I should have X-ray emission
post optical-peak. With the predicted fluxes well within the Chandra
limit in 10ksec, Gaia16apd offers the unique opportunity to constrain
theoretical models. The proposed observation will shed light on the
long standing mystery of what powers the luminous optical emission
from SLSN-I.

Sequence Number: 502664

Title : An outburst of the CCO 1E161348-5055: an accreting neutron star or a
peculiar binary magnetar?
PI: Rea
Abstract: The INS 1E161348-5055 is a Central Compact Object (CCOs) in the center
of the 2kr young SNR RCW103. It has been an intriguing source all
along. Several hypothesis about the nature of 1E1613 have been
proposed as a binary neutron star system, a very slow magnetar or even
a CV (see Pizzolato et al. 2008). The bright thermal X-ray emission of
other CCOs, and the low dipolar B field (~10^11 G), have been
interpreted as evidence of "hidden" strong magnetic fields within the
CCO crusts, burried by accretion. 1E1613 was instead considered an
outlier because of the lack of pulsation, but the presence of a
peculiar 6.4hr periodicity. Our undergoing Swift monitoring of 1E16134
show the source at a flux of a factor of 10 higher, and with a harder
spectrum (PL ~1.7) than usual (see figure in the link). Furthermore,
apparently Swift BAT detected a "possible"burst from this direction
(GCN 19547/GRB 160622A), although its association with the CCO is
still unclear (if any).

Sequence Number: 502663

Title : Understanding the Mass-Loss History of the Progenitors of Type IIn
Supernovae: SN 2016bkv
PI: Patnaude
Abstract: The mass-loss history of massive stars is one of the least understood
and yet fundamental aspects of stellar evolution. HOW and WHEN do
massive stars shed their massive envelopes? Is there a relationship
between the expulsion of the stellar envelope and core-collapse? These
central, yet open questions motivate the present investigation. In
regards to these questions, studying the evolution of a supernova
shock as it interacts with the ejected envelope of the progenitor
provides insight into how much mass was lost and perhaps most
importantly, when it was lost relative to core-collapse. X-ray
emission from the shocked gas probes the dynamics of the interaction
and, when combined with other ongoing and planned multi-wavelength
observations, serves to constrain properties of the surrounding
circumstellar gas and the end-stages of the progenitor's evolution. We
propose to study SN2016bkv in order to understand the final mass-loss
phase prior to the core-collapse of its progenitor.

Sequence Number: 401818

Title : An exceptionally cold neutron star in HETE J1900.1-2455
PI: Degenaar
Abstract: The ~1 km thick crust of neutron stars is strongly heated by nuclear
reactions during accretion outbursts, but cools in quiescence. HETE
J1900.1-2455 continously accreted since 2005, but in 2015 late Oct its
intensity dropped below the detection limit of MAXI. Swift
observations (Mar 7) fail to detect the source, implying Lx (0.5-10 keV) and a very cold neutron star crust of kT<65 eV. This is
highly unexpected, as the crust should have been significantly heated
during the ~9 yr outburst: our studies of 5 other sources after >1 yr
outbursts revealed hot neutron star crusts of >100 eV. This remarkable
result suggests that nuclear heating may not always be efficient, a
scenario that has never been considered to explain exceptionally cold
neutron stars such as SAX J1808.4-3658 and 1H1905+000. With a 30 ks
DDT, we can put firm constraints on the crust temperature in HETE
J1900 (kT~33 eV; Lx~2e30 erg/s), with important implications for
neutron star heating/cooling models.

Sequence Number: 703301

Title : Detecting an X-ray Counterpart to an Active TeV Flaring Event in the
M87 Jet
PI: Cheung
Abstract: M87 is currently in an active TeV flaring state with 7% Crab detection
March 7 (4.1 sigma; VERITAS), confirmed at 8% Crab on March 8 (3.6
sigma; MAGIC) satisfying threshold for triggering monitoring with all
three TeV telescopes. Previous TeV high-states lasted 1-2 week saw
day-scale flares at >3x the ~2% Crab quiescent flux. TeV flaring was
seen thrice previously since regular monitoring began in 2004. Sparse
1-2 week interval Chandra coverage in 2005 & 2008 gave ambiguous
results. In 2010 the first of 5 daily Chandra ToO exposures was
obtained in just <3 days from our trigger but the TeV flare subsided.
Thus the first Chandra observation in Mar 2016 should commence asap in
order to isolate TeV emission site in M87 via correlated variability
while in high TeV state. M87 nucleus and 0.8" offset jet knot HST-1
are known X-ray variable and Chandra can separate their
contributions.

Sequence Number: 703300

Title : Detecting an X-ray Counterpart to an Active TeV Flaring Event in the
M87 Jet
PI: Cheung
Abstract: M87 is currently in an active TeV flaring state with 7% Crab detection
March 7 (4.1 sigma; VERITAS), confirmed at 8% Crab on March 8 (3.6
sigma; MAGIC) satisfying threshold for triggering monitoring with all
three TeV telescopes. Previous TeV high-states lasted 1-2 week saw
day-scale flares at >3x the ~2% Crab quiescent flux. TeV flaring was
seen thrice previously since regular monitoring began in 2004. Sparse
1-2 week interval Chandra coverage in 2005 & 2008 gave ambiguous
results. In 2010 the first of 5 daily Chandra ToO exposures was
obtained in just <3 days from our trigger but the TeV flare subsided.
Thus the first Chandra observation in Mar 2016 should commence asap in
order to isolate TeV emission site in M87 via correlated variability
while in high TeV state. M87 nucleus and 0.8" offset jet knot HST-1
are known X-ray variable and Chandra can separate their
contributions.

Sequence Number: 703299

Title : Detecting an X-ray Counterpart to an Active TeV Flaring Event in the
M87 Jet
PI: Cheung
Abstract: M87 is currently in an active TeV flaring state with 7% Crab detection
March 7 (4.1 sigma; VERITAS), confirmed at 8% Crab on March 8 (3.6
sigma; MAGIC) satisfying threshold for triggering monitoring with all
three TeV telescopes. Previous TeV high-states lasted 1-2 week saw
day-scale flares at >3x the ~2% Crab quiescent flux. TeV flaring was
seen thrice previously since regular monitoring began in 2004. Sparse
1-2 week interval Chandra coverage in 2005 & 2008 gave ambiguous
results. In 2010 the first of 5 daily Chandra ToO exposures was
obtained in just <3 days from our trigger but the TeV flare subsided.
Thus the first Chandra observation in Mar 2016 should commence asap in
order to isolate TeV emission site in M87 via correlated variability
while in high TeV state. M87 nucleus and 0.8" offset jet knot HST-1
are known X-ray variable and Chandra can separate their
contributions.

Sequence Number: 703298

Title : Detecting an X-ray Counterpart to an Active TeV Flaring Event in the
M87 Jet
PI: Cheung
Abstract: M87 is currently in an active TeV flaring state with 7% Crab detection
March 7 (4.1 sigma; VERITAS), confirmed at 8% Crab on March 8 (3.6
sigma; MAGIC) satisfying threshold for triggering monitoring with all
three TeV telescopes. Previous TeV high-states lasted 1-2 week saw
day-scale flares at >3x the ~2% Crab quiescent flux. TeV flaring was
seen thrice previously since regular monitoring began in 2004. Sparse
1-2 week interval Chandra coverage in 2005 & 2008 gave ambiguous
results. In 2010 the first of 5 daily Chandra ToO exposures was
obtained in just <3 days from our trigger but the TeV flare subsided.
Thus the first Chandra observation in Mar 2016 should commence asap in
order to isolate TeV emission site in M87 via correlated variability
while in high TeV state. M87 nucleus and 0.8" offset jet knot HST-1
are known X-ray variable and Chandra can separate their
contributions.

Sequence Number: 703297

Title : Detecting an X-ray Counterpart to an Active TeV Flaring Event in the
M87 Jet
PI: Cheung
Abstract: M87 is currently in an active TeV flaring state with 7% Crab detection
March 7 (4.1 sigma; VERITAS), confirmed at 8% Crab on March 8 (3.6
sigma; MAGIC) satisfying threshold for triggering monitoring with all
three TeV telescopes. Previous TeV high-states lasted 1-2 week saw
day-scale flares at >3x the ~2% Crab quiescent flux. TeV flaring was
seen thrice previously since regular monitoring began in 2004. Sparse
1-2 week interval Chandra coverage in 2005 & 2008 gave ambiguous
results. In 2010 the first of 5 daily Chandra ToO exposures was
obtained in just <3 days from our trigger but the TeV flare subsided.
Thus the first Chandra observation in Mar 2016 should commence asap in
order to isolate TeV emission site in M87 via correlated variability
while in high TeV state. M87 nucleus and 0.8" offset jet knot HST-1
are known X-ray variable and Chandra can separate their
contributions.

Sequence Number: 703296

Title : Image D Of Huchra's Lensed Quasar: Waiting For The Other Shoe To Drop
PI: Pooley
Abstract: In mid-2013, image D of Huchra's Lens began fading precipitously in
the optical (as seen by OGLE). One expects corresponding brightness
changes in X-rays, as the X-ray region is thought to be smaller, by a
factor of 4, than the optical continuum region (Mosquera et al), but
with the changes occurring more rapidly. At the start of the 2014 OGLE
season (MJD 56826), image D was 0.7 mag fainter than in mid-2013. Our
analysis of archival Chandra data shows that there was no X-ray drop
on MJD 56815 compared to Chandra data from mid- to late-2013. This is
somewhat surprising, and it would be even more surprising if image D
were still as bright as on MJD 56815, given the continuing decline in
the optical (during 2015, image D had fallen ~2 mag below its mid-2013
level); this would (uncomfortably) imply that the X-rays and optical
come from separate non-concentric regions. We request a 30 ks
observation of 2237+0305 to determine whether image D has also fallen
by a factor of ~6 in X-rays.

Sequence Number: 502662

Title : SN2005ip awakens: an unprecedented glimpse of explosive mass-loss
10,000 years before core-collapse
PI: Mauerhan
Abstract: SNe interacting with circumstellar material (CSM) have raised critical
questions about the latest phases of massive-star evolution. SN 2005ip
is a case where >15 MSun of CSM was ejected by the luminous blue
variable (LBV) progenitor several years before core collapse,
reminiscent of Eta Car's historic eruption. So far we have no
explanation for the cause of pre-SN eruptions; potential factors
include late nuclear burning stages, or violent binary encounters.
After a decade of steadily fading interaction with stellar wind,
SN2005ip began interacting strongly this month with a distant dense
structure of CSM ejected 10,000 yr before the SN, providing an
unprecedentedly distant look-back time on the progenitor's pre-SN
mass-loss history. The CSM could have an origin similar to the ring
around SN1987A, also launched 10,000 yr before SN. We request DDT
ACIS-S observations of 2005ip before it fades, to measure the
interaction energy and mass of the CSM, in order to elucidate its
origin.

Sequence Number: 300391

Title : The accretion disk of a rare jet-driving symbiotic binary during its
brightest outburst in a ~century
PI: Lucy
Abstract: The current optical outburst (ATel#8653) of the symbiotic star
(interacting white dwarf [WD] + red giant) MWC 560, its brightest in
>87 years, provides a rare opportunity to examine the physics of jet
production in the otherwise well-understood context of WD accretion.
This proposal's goal is to use X-ray emission from the accretion-disk
boundary layer to characterize changes in the disk associated with
strong jet production/acceleration. MWC 560 drives a jet, and optical
spectra taken over 2 months during the peak of the last outburst, 26
years ago, showed Balmer absorption velocities increasing from 3000
km/s to their record velocity of 6000 km/s (Tomov et al. 1990).
300-2800 km/s Balmer troughs have just been observed, suggesting the
early phase of jet acceleration. Chandra will reveal whether the
jet-driving disk remains intact and brightens in X-rays (we expect the
boundary layer to remain optically thin) or the degree to which the
inner disk is evacuated (as in X-ray binaries).

Sequence Number: 300391

Title : The accretion disk of a rare jet-driving symbiotic binary during its
brightest outburst in a ~century
PI: Lucy
Abstract: The current optical outburst (ATel#8653) of the symbiotic star
(interacting white dwarf [WD] + red giant) MWC 560, its brightest in
>87 years, provides a rare opportunity to examine the physics of jet
production in the otherwise well-understood context of WD accretion.
This proposal's goal is to use X-ray emission from the accretion-disk
boundary layer to characterize changes in the disk associated with
strong jet production/acceleration. MWC 560 drives a jet, and optical
spectra taken over 2 months during the peak of the last outburst, 26
years ago, showed Balmer absorption velocities increasing from 3000
km/s to their record velocity of 6000 km/s (Tomov et al. 1990).
300-2800 km/s Balmer troughs have just been observed, suggesting the
early phase of jet acceleration. Chandra will reveal whether the
jet-driving disk remains intact and brightens in X-rays (we expect the
boundary layer to remain optically thin) or the degree to which the
inner disk is evacuated (as in X-ray binaries).

Sequence Number: 703295

Title : Catching a Changing Look Quasar as it retreats to the Shadows for the
Second Time
PI: Tremblay
Abstract: We propose an urgent, exciting, and short (30 ksec) Chandra DDT
observation of Mrk 1018, enabling a first-ever observation of a quasar
returning to an obscured Type 2 (narrow-lined) state *for the second
time*. In 1986, the source was identified as one of the first-known
changing look" quasars, transitioning from a Seyfert 1.9 to a
Seyfert 1 nucleus. This extreme variability was due either to dramatic
intermittency in the accretion rate, or because an eclipsing cloud
vacated our line of sight, revealing the broad line region. Last week,
in examining our new VLT/MUSE IFU data for this source (obtained as
part of the CARS survey, www.cars-survey.org), we were astonished to
discover that the source has just now reverted *back* to a
narrow-lined Seyfert 1.9. Optical photometry shows that the AGN has
dimmed by an entire magnitude over the past year, and shows no signs
of slowing. Chandra is urgently needed to directly test both
hypotheses (i.e., cloud passage vs. accretion rate change).

Sequence Number: 401817

Title : Confirming X-ray brightening of the PSR J2032+4127 binary system
PI: Ho
Abstract: We propose a 5 ks observation of the radio and gamma-ray pulsar PSR
J2032+4127 and its binary (Be-star) companion MT91-213. Even though
there are many known Be-neutron star binaries, this system is unique
in many ways, including its very long and eccentric orbit, proximity
(1.4 kpc), and careful radio monitoring and timing. Neutron stars in
these types of binaries usually undergo luminous X-ray outbursts
during periastron, as they accrete matter from their Be-star
companion. PSR J2032+4127 will reach periastron in early 2018, and the
anticipated X-ray outburst (and radio monitoring) will provide
important insights into the accretion process and physics of neutron
stars and their magnetic fields. Our proposed short observation is
needed in order to produce a baseline for the upcoming outburst,
especially with several other nearby X-ray bright sources.

Sequence Number: 502661

Title : The Young Type IIP Supernova ASASSN-16at
PI: Grupe
Abstract: We propose to observe a young (~5-day old), nearby (16 Mpc) type IIP
supernova ASASSN-16at with Chandra for 5ks. We tentatively detect the
supernova with Swift XRT. Chandra had observed the field in November
2005, but no X-ray source was found, strengthening the possibility
that the Swift detections are associated with the supernova. However,
precise Chandra astrometry is needed to establish the association.
Detections of SNe IIP this early are rare - only 3 have been detected
in X-rays within the first 10 days. Such very early phase X-ray
detection can put important constraint on its immediate circumstellar
exploding environment, which can subsequently probe the mass loss mode
of the RSG progenitor within a decade before the explosion.
Furthermore, the tentative Swift detection places ASASSN-16at among
the most luminous SNe IIP in X-ray, and the Chandra measurement will
test the recently proposed upper limit on the RSG progenitor mass loss
rate for this class of supernovae.

Sequence Number: 201084

Title : X-ray irradiation and evaporation of a likely ocean planet
PI: Wheatley
Abstract: The super-Earth transiting the bright K star HD97658 (V=7.7) has a
density impling a bulk composition dominated by water. X-ray/EUV
irradiation of the planet is expected to photodissociate the water
envelope and drive a hydrogen-rich wind that should be detectable at
Lyman-alpha with HST/STIS. We have HST transit observations scheduled
for Dec and Jan that are designed to detect the escaping hydrogen and
establish the presence of a water reservoir on HD97658b. This would be
the first signature of an evaporating ocean on an exoplanet. Here we
request Chandra observations to measure the mean X-ray flux of the
star in the hours preceding the two HST observations. This will allow
us to determine the energetic efficiency of atmospheric escape in the
case of detected absorption, or to place limits on the abundance of
water in the absence of absorption. Chandra coverage of both transits
will allow us to interpret variability in water loss in the context of
the changing radiation environment.

Sequence Number: 201084

Title : X-ray irradiation and evaporation of a likely ocean planet
PI: Wheatley
Abstract: The super-Earth transiting the bright K star HD97658 (V=7.7) has a
density impling a bulk composition dominated by water. X-ray/EUV
irradiation of the planet is expected to photodissociate the water
envelope and drive a hydrogen-rich wind that should be detectable at
Lyman-alpha with HST/STIS. We have HST transit observations scheduled
for Dec and Jan that are designed to detect the escaping hydrogen and
establish the presence of a water reservoir on HD97658b. This would be
the first signature of an evaporating ocean on an exoplanet. Here we
request Chandra observations to measure the mean X-ray flux of the
star in the hours preceding the two HST observations. This will allow
us to determine the energetic efficiency of atmospheric escape in the
case of detected absorption, or to place limits on the abundance of
water in the absence of absorption. Chandra coverage of both transits
will allow us to interpret variability in water loss in the context of
the changing radiation environment.

Sequence Number: 502660

Title : Search for an X-ray counterpart from a repeating Fast Radio Burst
PI: Scholz
Abstract: Fast radio bursts (FRBs) are a new class of ms bursts discovered using
the Parkes radio telescope (Thornton et al. 2013). FRBs appear to be
one-off events with very large dispersion measures (DM) that suggest
cosmological distances, but unknown origins. Last year, we discovered
the first non-Parkes FRB 121102, DM=557 pc cm^-3, 3x the predicted
Galactic column (Spitler et al. 2014). Remarkably, we detected ~10
more bright radio bursts in Arecibo data from June at the same DM. We
have just detected another burst on Nov 13th using GBT. The June
bursts suggest a period of 8s. This period is typical of magnetars.
This thus could be an extra-Galactic magnetar, and may solve the FRB
mystery. This sky position has yet to be observed by any X-ray
telescope other than ROSAT whose response is too soft to be useful. We
request Chandra DDT time to search for an X-ray counterpart which
would test the magnetar hypothesis and, crucially, localize the
source, thus enabling an ID of a galaxy host.

Sequence Number: 401816

Title : High Spatial/Temporal Resolution Chandra Follow-up of the 2015
outburst of the X-ray pulsar SMC X-2
PI: Li
Abstract: Accretion and propeller are the major processes driving the pulsar
evolution. SMC X-2, a 2.37s X-ray pulsar (Corbet+ 2000), is one of a
few important examples showing strong accretion outbursts and low
accretion propeller quiescences, occasionally. 2 close (2") possible
optical counterparts, a variable brighter Oe and a stable fainter Be,
have been reported (Schmidtke+ 2006). In 2015 Sep, Swift/BAT and
MAXI/GSC independently detected an outburst at 15 mCrab. A rapid XRT
ToO confirms the result with the best ever accurate localization at
<3.6". But still, depending on how the XRT astrometry is done, both
the reported counterparts can be real. While our analysis on the most
recent XRT data (WT) tentatively shows the spin period is by 0.001s
faster than the one detected by RXTE/ASCA in 2000, a more sensitive
data is required to confirm this. We thus request a 2.8ks timing mode
HRC-S observation to 1) determine the optical companion and 2) verify
spin-up history over the last 15 years.

Sequence Number: 703280

Title : Simultaneous Chandra and NuSTAR Observations of the Highly Obscured
AGN Candidate in NGC660.
PI: Annuar
Abstract: We are using NuSTAR to undertake a detailed investigation of the
obscured AGN population at D<15Mpc. Our latest target is NGC660 where
the presence of an AGN has been ambiguous. However, recently it was
observed to undergo a radio outburst which reveals a bright continuum
source (Argo et al. 2015), coincident with Chandra 2-8 keV emission
from one of the three point sources near the nucleus (<5"). This
confirms and pinpoints the X-ray position of the AGN. Comparisons of
the Chandra flux with the radio emission and other multiwavelength
luminosity indicators indicate that the X-ray flux is suppressed,
suggesting that it is absorbed by a high column of gas. A NuSTAR
observation for this object has been scheduled as part of our program.
The requested Chandra observation is essential to unambiguously
constrain the AGN and isolate it from other sources at <8 keV. When
combined with NuSTAR, we will then be able to accurately characterise
the 0.5-30 keV spectrum of the AGN for the first time.

Sequence Number: 100155

Title : Chandra Observations of Pluto's Escaping Atmosphere in Support of the
New Horizons Encounter with Pluto
PI: McNutt
Abstract: Current models of Pluto s extended atmosphere remain uncertain.
Applying knowledge gained from studying cometary X-ray emission,
Chandra ACIS-S photometric imaging of X-rays produced by CXE between
the solar wind and Pluto s atmosphere addresses both the atmospheric
density and the interaction of the solar wind with the extended
Plutonian atmosphere. An exploratory measurement on 24 February 2014
for 35 ksec provided a marginal X-ray emission signal from Pluto given
the low solar wind flux at the time. By increasing the observing time
by a factor of 4 (to 140 ksec), the tentative Cycle 15 detection will
be verified or much tighter upper limits on the neutral gas escape
rate will be determined. The timing of the observation is fixed in
time to coincide with the encounter of the New Horizons (NH)
spacecraft with Pluto, a unique in situ event in solar system
exploration. Chandra provides a unique, global and contemporaneous
X-ray measurement of the system.

Sequence Number: 100155

Title : Chandra Observations of Pluto's Escaping Atmosphere in Support of the
New Horizons Encounter with Pluto
PI: McNutt
Abstract: Current models of Pluto s extended atmosphere remain uncertain.
Applying knowledge gained from studying cometary X-ray emission,
Chandra ACIS-S photometric imaging of X-rays produced by CXE between
the solar wind and Pluto s atmosphere addresses both the atmospheric
density and the interaction of the solar wind with the extended
Plutonian atmosphere. An exploratory measurement on 24 February 2014
for 35 ksec provided a marginal X-ray emission signal from Pluto given
the low solar wind flux at the time. By increasing the observing time
by a factor of 4 (to 140 ksec), the tentative Cycle 15 detection will
be verified or much tighter upper limits on the neutral gas escape
rate will be determined. The timing of the observation is fixed in
time to coincide with the encounter of the New Horizons (NH)
spacecraft with Pluto, a unique in situ event in solar system
exploration. Chandra provides a unique, global and contemporaneous
X-ray measurement of the system.

Sequence Number: 401698

Title : Light Echoes from V404 Cyg
PI: Heinz
Abstract: In June 2013, V404 Cyg went into a bright outburst after 26 years of
quiescence. The source flux is now in decline. Swift observations
reveal the presence of four bright rings, caused by scattering off of
interstellar dust clouds between us and the source. This is only the
third fully resolved echo of a Galactic source. Because the distance
to the source is accurately known, it is possible to perform precision
dust tomography and calibrate the use of dust echoes as distance
measure. To reach the required sensitivity, avoid cross contamination
with dispersed spectra of the dust scattering halo, and be able to
accurately model and remove cosmic and particle backgrounds, gratings
observations cannot be used for this science, and we ask for a 30ksec
full frame imaging observation.

Sequence Number: 100155

Title : Chandra Observations of Pluto's Escaping Atmosphere in Support of the
New Horizons Encounter with Pluto
PI: McNutt
Abstract: Current models of Pluto s extended atmosphere remain uncertain.
Applying knowledge gained from studying cometary X-ray emission,
Chandra ACIS-S photometric imaging of X-rays produced by CXE between
the solar wind and Pluto s atmosphere addresses both the atmospheric
density and the interaction of the solar wind with the extended
Plutonian atmosphere. An exploratory measurement on 24 February 2014
for 35 ksec provided a marginal X-ray emission signal from Pluto given
the low solar wind flux at the time. By increasing the observing time
by a factor of 4 (to 140 ksec), the tentative Cycle 15 detection will
be verified or much tighter upper limits on the neutral gas escape
rate will be determined. The timing of the observation is fixed in
time to coincide with the encounter of the New Horizons (NH)
spacecraft with Pluto, a unique in situ event in solar system
exploration. Chandra provides a unique, global and contemporaneous
X-ray measurement of the system.

Sequence Number: 401697

Title : The Next Step for V404 Cyg
PI: Neilsen
Abstract: In May 1989, the black hole V404 Cyg exhibited some of the brightest,
most dramatic variability ever seen from a Galactic X-ray binary. The
spectacular variability, lasting only 1-2 weeks, was followed by a
slow 6 month decay. Given the extremity of the outburst and the
significant deviations from canonical BH behavior, little is
understood about the physics of this remarkable system. A new outburst
began on June 16, but how closely will V404 Cyg follow the BH track
after its initial fireworks have ended? P Cygni profiles are seen in
the optical (ATel 7669). Will V404 Cyg produce a massive X-ray disk
wind? A strong variable iron line has also been reported (ATel #7694).
We propose two 40 ks observations (~2 orbital periods), in 20-30 and
40-60 days, to study the variable Fe line and search for X-ray
absorption diagnostics of the growing wind during the later portions
of the outburst. Even on our time scale, we expect fluxes near 0.25-1
Crab and a factor of ~5 variability.

Sequence Number: 401696

Title : Detecing Super-Eddington Driven Winds in V404 Cyg
PI: King
Abstract: V404 Cyg has gone into outburst(ATEL 7646..7663). The light curve from
its last (1989) outburst was characterized by a dramatic rise starting
May 23 until May 30, where it then plummeted in X-ray flux (Zycki99),
unusual for X-ray binaries. The outburst was also very close to its
Eddington limit (Tanaka89, Zycki99). Super-Eddington accretion can
explain the bizarre light curve behavior, as ejection of accreting
shells driven by radiation pressure may have disrupted the disk and
caused the dramatic decrease in flux. V404 is now in outburst, and we
will examine its behavior with unprecedented spectral resolution with
the Chandra HETG.Based on our previous work with J17091-3624 (King14),
GRO 1655-40 (Miller08), and GRS 1915+105 (Miller in prep), we find
that 40 ksec is sufficient at detecting lines at >3 sigma. Finding
evidence for winds (or lack there of) will have vital implications for
outflow generation during Eddington accretion phases, feedback, and
growth of black holes.

Sequence Number: 401695

Title : Detecing Super-Eddington Driven Winds in V404 Cyg
PI: King
Abstract: V404 Cyg has gone into outburst(ATEL 7646..7663). The light curve from
its last (1989) outburst was characterized by a dramatic rise starting
May 23 until May 30, where it then plummeted in X-ray flux (Zycki99),
unusual for X-ray binaries. The outburst was also very close to its
Eddington limit (Tanaka89, Zycki99). Super-Eddington accretion can
explain the bizarre light curve behavior, as ejection of accreting
shells driven by radiation pressure may have disrupted the disk and
caused the dramatic decrease in flux. V404 is now in outburst, and we
will examine its behavior with unprecedented spectral resolution with
the Chandra HETG.Based on our previous work with J17091-3624 (King14),
GRO 1655-40 (Miller08), and GRS 1915+105 (Miller in prep), we find
that 40 ksec is sufficient at detecting lines at >3 sigma. Finding
evidence for winds (or lack there of) will have vital implications for
outflow generation during Eddington accretion phases, feedback, and
growth of black holes.

Sequence Number: 401694

Title : The brightening of M82: The intermediate mass black hole or ultra
luminous X-ray pulsar?
PI: Brightman
Abstract: Swift XRT monitoring of M82 has shown that the X-ray emission from the
galaxy has increased by a factor of ~4 from its usual 2-10 keV
luminosity of 1x10^40 ergs/s. Previous flux increases have been
attributed to the intermediate mass black hole candidate, X-1,
entering the thermal disk-dominated state (Feng & Kaaret 2010),
however the neighboring source, X-2, recently identified as an ultra
luminous pulsar (Bachetti et al 2014) has also been known to reach
10^40 ergs/s. At 4 arcsec separation, only Chandra can tell which
source is causing the current brightening. With an off-axis
observation with a sub array of pixels to mitigate pile-up, valuable
spectral constraints will be provided by Chandra. Furthermore, if this
Chandra observation is approved, we will trigger a NuSTAR ToO to
measure the high energy spectrum of the source, whichever it may be.

Sequence Number: 502493

Title : Mapping the evolution of SNhunt275 to shed light onto the last
evolutionary stages of Massive Stars
PI: MARGUTTI
Abstract: The mass-loss history of massive stars is one of the least understood
and yet fundamental aspects of stellar evolution. HOW and WHEN do
massive stars lose their hydrogen envelopes? This central, yet
still-open question motivates our investigation. Here we ask for
Chandra observations to map the evolution of the transient SNhunt275
on its way to become a Supernova. SNhunt275 was identified in 2013 as
a luminous outburst from a stellar object in NGC2770. The same star
gave rise to a luminous display earlier this year and recently
underwent a drastic re-brightening and spectral evolution which likely
prelude to a major explosion, in close similarity to SN2009ip. Our
primary goal is to constrain the density and location of the material
in the immediate environment of SNhunt275, and hence the mass-loss
history of its stellar progenitor over the last ~100 yrs. This is only
possible through deep X-ray observations that sample the emission
arising from the shock interaction with the medium.

Sequence Number: 502492

Title : Mapping the evolution of SNhunt275 to shed light onto the last
evolutionary stages of Massive Stars
PI: MARGUTTI
Abstract: The mass-loss history of massive stars is one of the least understood
and yet fundamental aspects of stellar evolution. HOW and WHEN do
massive stars lose their hydrogen envelopes? This central, yet
still-open question motivates our investigation. Here we ask for
Chandra observations to map the evolution of the transient SNhunt275
on its way to become a Supernova. SNhunt275 was identified in 2013 as
a luminous outburst from a stellar object in NGC2770. The same star
gave rise to a luminous display earlier this year and recently
underwent a drastic re-brightening and spectral evolution which likely
prelude to a major explosion, in close similarity to SN2009ip. Our
primary goal is to constrain the density and location of the material
in the immediate environment of SNhunt275, and hence the mass-loss
history of its stellar progenitor over the last ~100 yrs. This is only
possible through deep X-ray observations that sample the emission
arising from the shock interaction with the medium.

Sequence Number: 401693

Title : Snapshot observations of 2S1553-542: determination of the source
nature
PI: Lutovinov
Abstract: We propose to perform a snapshot observation of the transient source
2S1553-542, which demonstrated an outburst last three months. The
current outburst is a third one only detected from this source since
1975 (the second one was in 2007). Previously the source nature was
tentatively proposed as a X-ray pulsar (pulse period 9.3 sec) in the
Be binary system due to the outbursts activity. But no optical
counterpart was established till the moment. One of main reasons of
this is a lack of knowledge of exact coordinates of the source. The
proposed observations at the outburst decay stage is a unique chance
to determine the source coordinates with a high precision, to perform
follow-up observations in optical and infrared wavebands and establish
its nature. Additionally, based on the results of spectral analysis we
will determine if the source is still accreting at low level or we
observe the heated neutron star.

Sequence Number: 401692

Title : The Structure of the Accretion Flow in SAX J1808.4-3658 at Low
Luminosities.
PI: Patruno
Abstract: The accreting pulsar (AMXP) SAX J1808.4-4658 is now in outburst (ATel
#7346). Seven more have been observed, with pulsations at 401 Hz.
Recently, we made two key discoveries: i. the accretion disk of SAX
J1808 might be truncated close to the co-rotation radius (i.e., where
plasma co-rotates with the neutron star) even at the lowest
luminosities (1e33 erg/s). We suspect that this is due to a new type
of accretion flow: the "trapped dead disk" (see
Patruno+2015,arXiv:1504.05048). ii. we have phase-connected *all*
pulsations observed by RXTE (Patruno+, in prep.), having now a 13 year
baseline. This is unprecedented for any AMXP. If we phase connect *one
more outburst* we can constrain the proper motion and variations of
the semi-major axis for the fisrt time. We'd like to find pulsations
at low luminosities (during reflares) and conclusively determine
whether a disk extends down the co-rotation radius. Then phase connect
these pulsations with our previous 13-yr baseline.

Sequence Number: 502491

Title : Search for a Jet Break in the Short GRB 150423A
PI: Berger
Abstract: Understanding the collimation of short GRB jets is critical for
inferring their true energy release and event rate. This not only
impacts our understanding of these explosive events (e.g. energy
extraction and dissipation), but given their likely association to
neutron star binary mergers also feeds into the expected Advanced LIGO
merger rate, and the expected brightness of Advanced LIGO
electromagnetic counterparts. At the present only 4 short GRB jet
opening angle measurements have been made (by our group using Chandra
and XMM), so every additional measurement will have an impact on the
opening angle distribution. Here we request a single 25 ksec Chandra
observation on a timescale of about 7 days post-burst to measure the
decline rate relative to the XRT early data and hence to determine the
jet opening angle. The detection of a break will indicate a jet of
5-10 deg, while a non-detection will point to a broad outflow with >10
deg.

Sequence Number: 401691

Title : Seizing a rare opportunity to catch a disk wind in a neutron star
X-ray binary
PI: Degenaar
Abstract: In low-mass X-ray binaries (LMXBs) a neutron star or a black hole
accretes matter from a low-mass companion star via an accretion disk.
Outflows in the form of X-ray disk winds and radio jets are
universally linked to the accretion process. During low-luminosity
(<1E37 erg/s) "hard" X-ray states radio jets prevail, whereas disk
winds are only seen during high-luminosity (>1E37 erg/s) "soft"
states. Disk winds are now routinely detected and studied in black
hole LMXBs, but much less is known about such winds in neutron star
LMXBs, which are often fainter. Here we propose to seize the rare
opportunity to study the disk wind in a transient neutron star LMXB,
which is currently exhibiting an outburst and entered an X-ray bright
soft state on April 4th. Swift/XRT observations reveal ionized
absorption features at high (>5 keV) energies that are indicative of a
disk wind in this system. Only with the unprecedented spectral
resolution of Chandra/HETG can these features studied in detail.

Sequence Number: 300338

Title : GK Persei in the current dwarf-nova-like outburst
PI: Orio
Abstract: GK Persei is the "all-in-one" white dwarf interacting binary. It can
be classified as a nova (outburst in 1901), as a symbiotic because of
the red giant companion, as a magnetic system (it is an intermediate
polar or IP), as a dwarf nova (every ~2 years it has repeated
disk-instability-related outbursts) and even as a "mini-supernova
remnant" (it has just "made the news" again, with a Chandra
press-release, because of its luminous at-all-wavelengths, and still
expanding shell ejected in 1901). In March a new dwarf- nova-like
outburst started and we have been monitoring it with Swift. The count
rate in the Swift XRT varies between about 1 and about 2 cts/s (ATels
7246, 7248) and the Swift spectrum indicates a main component of the
X-ray flux, a thermal one, that peaks at energy well above the Swift
range - for this reason we have applied also for NuSTAR time. However,
only grating spectra reveal the full physical picture: we plan to
study how GK Per is evolving.

Sequence Number: 201026

Title : The dim state of RW Aur
PI: Schneider
Abstract: In Oct 2014 the well studied young star RW Aur A was unexpectedly
obscured by the tidally disrupted disk of its close but resolved
binary companion RW Aur B (Petrov et al. 2015,
arxiv.org/abs/1503.04158). Such events are extremely rare and provide
us with a chance to directly measure the gas-to-dust ratio of
protoplanetary disk material. We can measure this ratio by comparing
the differences in X-ray absorption (caused by gas) and optical
absorption (caused by dust) before and during the obscuration event.
So far, estimates are highly model dependent; this observation offers
an actual measurement to tightly constrain planet formation models
that currently suffer from our ignorance of reliable disk gas masses.
Such dimming events are short (the only known other such event lasted
180 days) and unpredictable and thus require quick follow-up
observations when seen in a key system such as RW Aur, where the
bright state is already well characterized at optical and X-ray
wavelengths.

Sequence Number: 502490

Title : Calibration of the ACIS GRADED mode using the Cas A CCO
PI: Posselt
Abstract: The potential temperature (T) decline of the Central Compact Object
(CCO) in the Cas A SNR is important to probe fundamental physics via
the study of neutron star cooling. An exciting T-decline found from
GRADED(G)-mode observations is called into doubt by results from
subarray FAINT (F) observations. Possible reasons are pile-up and
grade migration in the G-mode. Cross-calibration of the different
instrument setups was not possible previously due the poorly known
spatial distribution of the filter contaminant. We propose a
calibration subarray F observation of Cas A with the CCO centered at
exactly the same chip position as in a contemporaneous G-mode
observation. This will allow us to obtain a contaminant-independent
assessment of the G-mode effects on the CCO spectrum. With this, one
can re-calibrate the past 19 G-mode data sets. Such a
cross-calibration will be also useful to the general X-ray community.

Sequence Number: 401690

Title : Chandra Observation of 'GRB 150301C' / [PFH2005] 622
PI: Burrows
Abstract: On March 1, 2015, Swift responded to a strong hard X-ray flare (1000
cps) in the direction of M31, lasting 20 s. It was initially
classified as a possible GRB and given the name GRB 150301C. The lack
of a soft X-ray counterpart was very puzzling. Further analysis showed
a very weak counterpart at about 100 s after the trigger, but this
faded rapidly. The only sources similar in terms of BAT to XRT flux
ratio are short GRBs and SGR flares, both of which are much shorter in
the duration of the hard X-ray burst than this object. XRT found a
single very faint, but fading, object within the BAT error circle,
coincident with a known X-ray source found in an XMM survey of M31:
[PFH2005] 622. Within the XMM source error circle there are 3 optical
sources. We request a 20 ks Chandra observation to localize the
position of the [PFH2005] 622 and to determine whether it is currently
brighter than the XMM flux of 6.9E-15 cgs.

Sequence Number: 703155

Title : X-ray Flux of the Narrow Line Seyfert 1 Galaxy WPVS 007 during an
unprecidented low UV flux state
PI: Grupe
Abstract: We have monitored the Narrow Line Seyfert 1 galaxy WPVS 007 with Swift
since 9.5 years. During this time it has shown a gradual decline in
its UV flux. While this is somewhat expected, because WPVS 007 has
shown an evolution of broad absorption lines seen by HST (Leighly et
al. 2009), in the February 21 Swift observation we noticed a sudden
drop in it's UV M2 magnitude/flux. A new Swift observation on February
28 not only confirmed this low state, it even showed that the UV flux
had dropped even more to an unprecedented low state in the UV since we
have started monitoring WPVS 007 in October 2005! We were just grated
to continue with weekly monitoring with Swift for the next few weeks
to follow the UV flux. However, we need to compare this UV flux with
the current flux in X-rays. While WPVS 007 showed X-ray flaring in
2010 and 2011, stacking Swift data since 2011 suggest that it has
decayed also in X-rays. WPVS 007 is a link between BAL QSOs and NLS1.

Sequence Number: 401689

Title : X-ray follow-up of a fast radio burst
PI: Petroff
Abstract: A new class of bright, isolated, potentially extragalactic pulses
called fast radio bursts (FRBs) is emerging in radio surveys. Only a
handful of sources are known to-date. No host galaxies or progenitors
have been identified, and some of the population s most basic
properties are still being determined. The only FRB ever followed-up
at X-ray wavelengths showed no transient X-ray emission in
observations beginning 8 hours after the event. Rapid response is
needed to determine if an X-ray counterpart exists. This would be the
first multi-wavelength detection of an FRB. Swift is unable to make
these observations as the source may be too faint for Swift and at the
moment the Swift telescope is moon constrained and cannot take
observations on this source.

Sequence Number: 401688

Title : Simultaneous UV and X-ray spectroscopy with HST and Chandra: observing
wind accretion onto a NS
PI: Oskinova
Abstract: We propose a direct experiment to probe the theory of HMXBs. Currently
we conduct the HST survey of HMXBs (PI Oskinova). The HMXB 4U1700-38
will be observed on Feb 22. From the analysis of the STIS spectra we
will determine mass-loss rate, wind velocity and clumping in the donor
star. We need simultaneously HETGS data to test how X-rays respond to
the changes in the wind. Such experiment was never done before. The
HETGS spectra will probe absorption, variability, and emission lines.
Simultaneous X-ray and UV observations will yield an unprecedented
insight on the processes operating in HMXBs. Chandra observed
4U1700-37 in 2003 (id 657) but in different phase. The RGS spectrum is
relatively featureless, while emission lines are prominent in the
HEGTS range. The HEG+MEG count rate varies erratically between 0.2 cps
and 20 cps. We request 15 ks to fully characterize the X-ray behavior.
Zero order will be most likely piled up, the +1 and -1 order will be
fully useful.

Sequence Number: 703154

Title : A second look for variability in the exceptional Swift J123205.1-1056
PI: Levan
Abstract: Swift J123205.1-1056 is a short, soft outburst detected by Swift. In
the error box is an AGN at z=0.134. CXO observations reveal a second
X-ray source on the stellar field of this AGN. If associated (the
probability of chance alignment is low) it has L_X ~ 1e43 ergs/s. This
luminosity suggests either an "afterglow"-like event, or if persistent
a hyperluminous, non-nuclear X-ray source. In the former case it is
possible given the softness of the burst that we may be observing a
tidal flare-like event, in which case a WD-IMBH disruption within a
globular cluster in the galaxy is possible (this is a luminous galaxy
that may contain a high specific frequency of globular clusters, but
has little/no star formation). A repeat of the earlier CXO
observations will allow us to assess variability in the source. Strong
variability would point to a transient event, most likely related to
the gamma-rays. No variability would imply a persistent HLX, but would
still be of considerable interest.

Sequence Number: 502489

Title : Understanding the nature of the peculiar transient Swift
J123205.1-105602
PI: Troja
Abstract: Swift recently triggered on a short duration transient dubbed Swift
J123205.1-105602. Its unusual soft spectrum seems not to be consistent
with a typical short-hard GRB, and its nature is still not well
understood. An optical counterpart was found at the edge of a nearby
galaxy at redshift z=0.093, placing this event within the sensitivity
of advanced LIGO/Virgo. The X-ray emission detected by the Swift/XRT
appears constant, which is also unusual for a typical GRB afterglow.
We request rapid Chandra observations in order to: 1) accurately
localize the X-ray transient, robustly associate it to the optical
counterpart, and eventually detect possible contaminating sources
within the XRT point spread function; 2) constrain the spectral shape
in order to better understand the nature of this object (e.g. neutron
star merger, shock breakout, tidal disruption event).

Sequence Number: 502488

Title : The unprecedented metamorphosis of SN2014C
PI: MARGUTTI
Abstract: The mass-loss history of massive stars is one of the least understood
yet fundamental aspects of stellar evolution. HOW and WHEN do massive
stars lose their hydrogen envelopes? This central, still-open question
motivates our present investigation. Here we ask for a continuation of
our Chandra program to map the unique situation of the interaction of
a hydrogen-stripped supernova 2014C with a thick, hydrogen-rich shell
ejected by the progenitor star, as part of our multi-wavelength (mm to
gamma-rays) follow-up. Our primary goal is to constrain the density
and location of the material in the immediate environment of SN2014C,
and hence the mass-loss history of its stellar progenitor.

Sequence Number: 502487

Title : The unprecedented metamorphosis of SN2014C
PI: MARGUTTI
Abstract: The mass-loss history of massive stars is one of the least understood
yet fundamental aspects of stellar evolution. HOW and WHEN do massive
stars lose their hydrogen envelopes? This central, still-open question
motivates our present investigation. Here we ask for a continuation of
our Chandra program to map the unique situation of the interaction of
a hydrogen-stripped supernova 2014C with a thick, hydrogen-rich shell
ejected by the progenitor star, as part of our multi-wavelength (mm to
gamma-rays) follow-up. Our primary goal is to constrain the density
and location of the material in the immediate environment of SN2014C,
and hence the mass-loss history of its stellar progenitor.

Sequence Number: 502486

Title : The unprecedented metamorphosis of SN2014C
PI: MARGUTTI
Abstract: The mass-loss history of massive stars is one of the least understood
yet fundamental aspects of stellar evolution. HOW and WHEN do massive
stars lose their hydrogen envelopes? This central, still-open question
motivates our present investigation. Here we ask for a continuation of
our Chandra program to map the unique situation of the interaction of
a hydrogen-stripped supernova 2014C with a thick, hydrogen-rich shell
ejected by the progenitor star, as part of our multi-wavelength (mm to
gamma-rays) follow-up. Our primary goal is to constrain the density
and location of the material in the immediate environment of SN2014C,
and hence the mass-loss history of its stellar progenitor.

Sequence Number: 703152

Title : A High-resolution Spectrum of an Unprecedented Tidal Disruption Event
PI: Miller
Abstract: ASASSN-14li is the best possible tidal disruption flare (TDF). Its
host galaxy is at z = 0.02, whereas the prior X-ray bright event
(Swift J16444) was at z = 0.35. The position of this transient is
within 0.04" of the host galaxy. The source was previously quiescent,
and the optical spectrum - both before and after the flare - are
inconsistent with an active Seyfert nucleus. The most recent flux (Dec
2) measured with the Swift XRT is 2 E-11 erg/cm2/s in the 0.2-2.0 keV
band. A moderately deep integration will give a spectrum that should
compare well with Seyfert spectra. There is only weak galactic
absorption along the line of sight to this source (few E+20 cm^-2),
meaning that the low temperature emission (kT = 66 eV) will give an
excellent spectrum at long wavelengths. If the disrupted gas is
illuminated by the central engine, it is reasonable to expect
optically thin line emission on top of a thermal continuum. Please
see: http://www.astronomerstelegram.org/?read=6777

Sequence Number: 703152

Title : A High-resolution Spectrum of an Unprecedented Tidal Disruption Event
PI: Miller
Abstract: ASASSN-14li is the best possible tidal disruption flare (TDF). Its
host galaxy is at z = 0.02, whereas the prior X-ray bright event
(Swift J16444) was at z = 0.35. The position of this transient is
within 0.04" of the host galaxy. The source was previously quiescent,
and the optical spectrum - both before and after the flare - are
inconsistent with an active Seyfert nucleus. The most recent flux (Dec
2) measured with the Swift XRT is 2 E-11 erg/cm2/s in the 0.2-2.0 keV
band. A moderately deep integration will give a spectrum that should
compare well with Seyfert spectra. There is only weak galactic
absorption along the line of sight to this source (few E+20 cm^-2),
meaning that the low temperature emission (kT = 66 eV) will give an
excellent spectrum at long wavelengths. If the disrupted gas is
illuminated by the central engine, it is reasonable to expect
optically thin line emission on top of a thermal continuum. Please
see: http://www.astronomerstelegram.org/?read=6777

Sequence Number: 401686

Title : A second HLX-1-like object in CXO J122518.6+144545
PI: Heida
Abstract: Intermediate mass black holes are crucial as building blocks for
supermassive BHs, but observational evidence for their existence is
still scarce. The brightest ULXs may be good IMBH candidates: the
strongest case is ESO 243-49 HLX-1 (Farrell et al. 2009), an X-ray
source that reaches a luminosity of more than 10E42 erg/s. It is
thought to host a BH of ~20,000 solar masses. Up until now, HLX-1 is
the only known object of its kind. Most candidate ULXs with comparable
luminosities have turned out to be background AGN. Finding more HLX-1
like objects would be an important step forward in the search for
IMBHs. We have investigated the X-ray source CXOJ122518.6+144545
(J1225; Jonker et al. 2010) with Chandra. It was found in an
observation from 2008, at a luminosity of ~2E41 erg/s, making it the
second most luminous ULX after HLX-1. We did not detect the source in
November 2012 and in April and July 2014, but in our last observation
on November 20 it was again visible at ~5E40 erg/s.

Sequence Number: 401685

Title : A second HLX-1-like object in CXO J122518.6+144545
PI: Heida
Abstract: Intermediate mass black holes are crucial as building blocks for
supermassive BHs, but observational evidence for their existence is
still scarce. The brightest ULXs may be good IMBH candidates: the
strongest case is ESO 243-49 HLX-1 (Farrell et al. 2009), an X-ray
source that reaches a luminosity of more than 10E42 erg/s. It is
thought to host a BH of ~20,000 solar masses. Up until now, HLX-1 is
the only known object of its kind. Most candidate ULXs with comparable
luminosities have turned out to be background AGN. Finding more HLX-1
like objects would be an important step forward in the search for
IMBHs. We have investigated the X-ray source CXOJ122518.6+144545
(J1225; Jonker et al. 2010) with Chandra. It was found in an
observation from 2008, at a luminosity of ~2E41 erg/s, making it the
second most luminous ULX after HLX-1. We did not detect the source in
November 2012 and in April and July 2014, but in our last observation
on November 20 it was again visible at ~5E40 erg/s.

Sequence Number: 502485

Title : Deep Chandra observations to put the deepest limits to the density of
the environment around a Type Iax SN
PI: MARGUTTI
Abstract: PSN J12215757+0428185 is a young Type Iax SN. It exploded in M61 and
it is the nearest Type Iax ever found. Here we ask for 20ks of Chandra
observations to constrain the density of the very close environment,
shaped by the mass-loss history of the progenitor system before the
explosion. This observation will allow us constrain the nature of the
progenitor system of this new kind of stellar explosions.

Sequence Number: 703151

Title : An unusual brightening of a non-active galaxy nucleus
PI: Feng
Abstract: NGC 247 is a dwarf or intermediate spiral galaxy at a distance of 3.4
Mpc. Past observations suggest that there was no activity of the
nuclear black hole. We conducted an XMM observation of NGC 247 on 2014
July 1, which serendipitously detected a bright X-ray source
coincident with the nuclear position (within 2 arcsec) with a
luminosity of 2E39 erg/s in 0.3-10 keV. The most recent observation
before that one was made on 2011 Feb 1 with Chandra. There was no
detection in the nuclear region, giving an upper limit of 1E37 erg/s.
If the new X-ray source is indeed due to the nuclear black hole
activity, its sudden brightening suggests that it may have tidally
disrupted a star some time between 2011 and 2014, or start to accrete
a stream of gas at a low rate. Either will be of great interest due to
its rarity and the small distance. A sub-arcsecond position accuracy
is needed to determine if the X-rays arise from the nucleus.

Sequence Number: 703150

Title : A candidate 30,000 solar mass black hole
PI: Gallo
Abstract: The target of this request is a newly discovered 30,000 solar mass
black hole candidate. As part of a follow-up spectroscopic campaign of
SDSS dwarf galaxies with optical signatures of AGN activity (Reines+
2014, ApJ, 775, 24), we recently acquired high resolution
Magellan/MagE spectra of a ~10^9 solar mass galaxy with narrow line
signatures of an AGN. The MagE spectrum clearly reveals the presence
of a broad H_alpha component that was only marginally detected in the
SDSS spectrum. Using standard virial techniques, the measured FWHM and
luminosity correspond a black hole mass of 30,000 solar masses. The
galaxy is a face-on disky dwarf with low Galactic absorption at a
distance of ~100 Mpc. We request 20 ksec with ACIS-S. In conjunction
with the optical diagnostics, the detection of a >10^40 erg/s, point
like X-ray source at a position consistent with the galaxy nucleus
would provide compelling evidence that this dwarf galaxy hosts the
smallest supermassive black hole reported to date.

Sequence Number: 502479

Title : Measuring the period derivative of the newly discovered magnetar SGR
1935+2154
PI: Rea
Abstract: Chandra observed SGR 1935+2154's outburst on the 15th and 28th of July
2014 for 9ks (ACIS-S, TE-mode) and 75ks (ACIS-S CC-mode). We detected
for the first time highly significant, >10sigma, pulsations at a
period of 3.24498(1) s (1 sigma c.l.), confirming it as a magnetar
candidate. Folding directly with this period the first observation we
detect the signal at a lower significance, deriving a period
derivative upper limit of about 2x10^-10 s/s was inferred. Swift
cannot see the signal because the source is too faint. We have
activated our XMM-Newton ToO program to keep monitoring the source,
but the XMM visibility will start on September 27th. We ask here for a
30ks DDT observation with ACIS-S CC-mode around late August to keep
the phase-coherence of our timing solution. This will allow the
determination of the period derivative of this new magnetar, crucial
to define the dipolar surface magnetic field of this object, then
identifying it as a highly-dipolar or low-dipolar magnetar.

Sequence Number: 200968

Title : The new outburst of the EXor V1180 Cas as observed at X and NIR
wavelengths
PI: Nucita
Abstract: EXORs are pre-main sequence stars that show recurrent luminosity
changes of short duration superposed to longer quiescence periods, see
e.g. Audard et al. 2014. Although a general consensus exists about the
nature of such outbursts (i.e. events of enhanced magnetospheric
accretion from the circumstellar disk), the physical mechanisms
regulating the outbursts and how these latter affect the circumstellar
disk structure and its evolution are not clarified yet. We recently
started an observational programme on this class of objects (EXORCISM,
EXOR OptiCal and Infrared Systematic Monitoring, Antoniucci et al.
2013). Optical and near-IR studies of EXORs rapidly increased in the
last decade but little is known about the X-ray properties, in
particular whether X-rays come from the corona of the star (being in
this case unaffected by the outbursts) or, conversely, originate in
accretion events.

Sequence Number: 401615

Title : Chandra/H.E.S.S. follow-up of PSR B1259-63 gamma-ray flare
PI: Bordas
Abstract: PSR B1259-63 is undergoing a flare emission in gamma-rays (ATel
#6204). Such a flare was observed for the first time in 2010,
accounting for almost 100% of the pulsar spin-down power. No flare
counterpart at higher/lower energies was observed at that time,
although the unexpected nature of the event made its MWL coverage
rather poor. We ask for Chandra DDT observations of PSR B1259-63 to
search for the flare X-ray counterpart (2 pointings x 5ksec each
during the next nights) and to monitor itsX-ray/TeV evolution (2
pointings x 5 ksec = 20 ksec from June 16th), in which H.E.S.S. will
observe the source simultaneously. The nature of the GeV flare and its
connection to the X-ray/TeV emission observed during PSR B1259-63
periastron passage makes simultaneous observations crucial. Next
Cherenkov observations will not be possible until 2021. No other X-ray
observatories are available for the requested dates (Swift XRT may not
be available next nights, see GCN 16349).

Sequence Number: 401614

Title : Chandra/H.E.S.S. follow-up of PSR B1259-63 gamma-ray flare
PI: Bordas
Abstract: PSR B1259-63 is undergoing a flare emission in gamma-rays (ATel
#6204). Such a flare was observed for the first time in 2010,
accounting for almost 100% of the pulsar spin-down power. No flare
counterpart at higher/lower energies was observed at that time,
although the unexpected nature of the event made its MWL coverage
rather poor. We ask for Chandra DDT observations of PSR B1259-63 to
search for the flare X-ray counterpart (2 pointings x 5ksec each
during the next nights) and to monitor itsX-ray/TeV evolution (2
pointings x 5 ksec = 20 ksec from June 16th), in which H.E.S.S. will
observe the source simultaneously. The nature of the GeV flare and its
connection to the X-ray/TeV emission observed during PSR B1259-63
periastron passage makes simultaneous observations crucial. Next
Cherenkov observations will not be possible until 2021. No other X-ray
observatories are available for the requested dates (Swift XRT may not
be available next nights, see GCN 16349).

Sequence Number: 502271

Title : Late-time X-rays to constrain the true energy, jet geometry and burst
environment of a GRB from the early Universe (z~6)
PI: MARGUTTI
Abstract: Among the most important parameters to constrain the GRB physics (both
jet launching mechanism and progenitor) are the energy scale, jet
geometry and the burst environment. Those can only be estimated
through broadband modeling of the late afterglow emission (radio to
X-rays). Of particular interest is to constrain the properties of the
z>6 population of GRBs that sample the star formation in the early
Universe (<1Gyr), and understand if they have unique properties when
compared to the overall population. This can only be done if reliable
estimates of the intrinsic properties of high-z GRBs and their
environments are available. Only 3 GRBs have been spectroscopically
confirmed at z>6 (050904, 080913, 090423). GRB140515A at z=6.32 offers
the opportunity to expand the sample. Chandra data acquired at
t+10days (after the flares) are crucial to map the spectrum above the
cooling frequency, thus enabling us to determine the true energy, jet
opening angle and environment of a rare z>6 GRB.

Sequence Number: 401613

Title : A Harder Look at the Bursting Pulsar
PI: Miller
Abstract: Observations of GRO J1744-28 with Chandra and NuSTAR reveal confusing
but potentially very revealing structure within the Fe K region. The
complex is either due to a very odd combination of charge states
within cospatial gas, or it represents double-horned emission line
structure from a truncated accretion disk. This is a significant
challenge to basic ideas of accretion in low-mass X-ray binaries, HETG
resolution can solve it.

Sequence Number: 401613

Title : A Harder Look at the Bursting Pulsar
PI: Miller
Abstract: Observations of GRO J1744-28 with Chandra and NuSTAR reveal confusing
but potentially very revealing structure within the Fe K region. The
complex is either due to a very odd combination of charge states
within cospatial gas, or it represents double-horned emission line
structure from a truncated accretion disk. This is a significant
challenge to basic ideas of accretion in low-mass X-ray binaries, HETG
resolution can solve it.

Sequence Number: 401612

Title : A rare opportunity to resolve the emission line complex in GRO
J1744-28
PI: Kennea
Abstract: Discovered Dec 1995, GRO J1744-28, AKA "The Bursting Pulsar", is one
of only two known objects to exhibit Type-II X-ray bursts. That
outburst lasted ~6 months, and since it has remained in quiescence.
Recently a coordinated effort by Swift, MAXI and Fermi confirmed GRO
J1744-28 to be in its first outburst in ~18 years. With Chandra we
entered the era of high resolution X-ray spectra, however Chandra has
only observed GRO J1744-28 in quiescence, obtaining a very poor
spectrum. ASCA observations (Nishiuchi et al., 1999) detected a 6.7
keV Iron line feature, which is strongly detected in new observations
by Swift. However, the poor spectral resolution of ASCA and XRT do not
allow us to discern the real nature of this feature. With such high
accretion rate, we might expect that the line complex is a blend of
neutral and high ionized lines from disk wind. Only Chandra HETG
observations have the sufficient resolution to pin down the nature of
the X-ray emission lines in GRO J1744-28.

Sequence Number: 401611

Title : The dynamical X-ray nebula powered by the high-mass binary PSR
B1259-63/LS 2883
PI: Pavlov
Abstract: PSR B1259-63/LS 2883 is the famous eccentric gamma-ray binary
(Pbin=3.4 yr, e=0.87) in which a pulsar orbits a massive O-type star.
Using ACIS observations of 2011 December 17 and 2013 May 19, 62 ks
each, we unexpectedly detected an extended (of about 4'' size)
structure, apparently moving away from the binary with v = 0.05c
(arXiv:1312.2654). Such a moving X-ray nebula has never been seen
before. An additional observation before 2014 January 30 is needed to
distinguish between two different interpretations of the extended
emission: (1) a fast-moving cloud of relativistic electrons loaded
with a large amount of baryonic matter; (2) a variable extrabinary
shock in the pulsar wind outflow. If (1) is correct, we will see the
cloud at the same position angle as in May 2013, while the shock would
be seen at a substantially different position angle (corresponding to
the orbital position change since May 2013; see
http://home.gwu.edu/~kargaltsev/B1259.html) if (2) is correct.

Sequence Number: 502269

Title : X-rays to probe the environment and the progenitor of Type Ia SN2014J
PI: MARGUTTI
Abstract: SN2014J has been recently discovered in M82, at a very close distance
of 3.7 Mpc. The spectra indicates a Type Ia supernova explosion. Type
Ia Supernovae have been employed as cosmic ladders to reveal the
accelerating Universe. In spite of their importance for Cosmology, a
key, fundamental question still remain open: Which stars are the
progenitors of these cosmic standards? We ask for deep X-ray
observations, to probe the environment around SN2014J down to
unprecedented limits. By timing the X-ray observations to the time of
the optical peak, and using the formalisms I developed in Margutti
2012 (ApJ 751 134) I will be able to probe densities as low as a few
d-10 Msun/yr (or a few particle/cm3), thus enabling us to distinguish
between symbiotic and double-degenerate progenitors. These limits
would be a factor 10 deeper than the any other limit presented in the
literature so far. It is also possible that this study will lead to
the first detection of X-ray radiation from a Type Ia SN.

Sequence Number: 200967

Title : X-ray driven evaporation of exoplanet atmospheres: discovery of a
uniquely suited test system
PI: Poppenhaeger
Abstract: The evaporation of exoplanetary atmospheres is thought to be driven by
high-energy irradiation. However, the actual mass loss rates are not
well constrained. Co-I Kipping has recently discovered that the star
KOI-314, an M1V dwarf at 65 pc distance, is orbited by two earth-sized
planets, the inner one of them rocky and the outer one gaseous (P_orb
= 14d and 23d). Other recent works have shown an abundance of small
rocky planets in very close orbits around their host stars, suggesting
that the stellar high-energy irradiation evaporates away gaseous
envelopes. KOI-314 is the first nearby system in which earth-sized
planets of both types are detected, allowing us to constrain the
efficiency of planetary evaporation if the stellar X-ray irradiation
is measured. We therefore propose a 10 ks Chandra ACIS-S pointing to
determine the stellar X-ray luminosity and hardness ratio. The
accuracy of the orbital solution decreases quickly due to
Transit-Timing Variations, which is why we ask for DDT.

Sequence Number: 401611

Title : The dynamical X-ray nebula powered by the high-mass binary PSR
B1259-63/LS 2883
PI: Pavlov
Abstract: PSR B1259-63/LS 2883 is the famous eccentric gamma-ray binary
(Pbin=3.4 yr, e=0.87) in which a pulsar orbits a massive O-type star.
Using ACIS observations of 2011 December 17 and 2013 May 19, 62 ks
each, we unexpectedly detected an extended (of about 4'' size)
structure, apparently moving away from the binary with v = 0.05c
(arXiv:1312.2654). Such a moving X-ray nebula has never been seen
before. An additional observation before 2014 January 30 is needed to
distinguish between two different interpretations of the extended
emission: (1) a fast-moving cloud of relativistic electrons loaded
with a large amount of baryonic matter; (2) a variable extrabinary
shock in the pulsar wind outflow. If (1) is correct, we will see the
cloud at the same position angle as in May 2013, while the shock would
be seen at a substantially different position angle (corresponding to
the orbital position change since May 2013; see
http://home.gwu.edu/~kargaltsev/B1259.html) if (2) is correct.

Sequence Number: 401610

Title : Catching the rebirth of a radio millisecond pulsar
PI: Patruno
Abstract: On 2013 Dec 10 we have discovered with a Swift/XRT observation, that
the low mass X-ray binary (LMXB) XSS J12270-4859 has recently changed
state from a quiescent-LMXB into a new anomalous faint state with no
signatures of accretion (ATel #5647). An NTT optical observation
suggests a transition around December 2012 in the opposite direction
to that of the "missing link" PSR J1023+0038 (that switched from a
radio millisecond pulsar (MSP), into an LMXB, Stappers et al.2013,
Patruno et al. 2013). A MSP may therefore be now active in XSS J12270.
We are currently completing the analysis of Parkes data to search for
the putative MSP. The Swift/XRT shows a faint source (1e32-1e33
erg/s). We want now to characterize the spectral behaviour with a 30
ks Chandra pointing. If we do not detect radio pulsations Chandra can
potentially tell us if the pulsar (and pulsar wind) are on even if the
radio pulsar is undetectable (as our preliminary Parkes analysis seems
to suggest).

Sequence Number: 502268

Title : Constraining the progenitor mass-loss and shock parameters around a
very unusual explosion: SN2013ge
PI: MARGUTTI
Abstract: Recent discoveries have shaken our current classification scheme of
supernova explosions. SN2013ge is such a case.The spectra we obtained
within 2 hours since discovery (on Nov 8th) revealed a very unusual
and blue continuum with no sign of H or He. Additionally, the
broadband light-curve of this transient showed an early blue peak
whose origin is unclear. Together, these findings place SN2013ge
outside ANY previously known SN category. We ask for a Chandra
observation to place a solid limit to the environment density (and
hence reveal the mass-loss history of the progenitor) and distinguish
between progenitor types. These observations will also allow us to
constrain the energy density in magnetic fields, a key but poorly
known parameter in SN shock physics. These observations are part of a
multi-wavelength program which includes optical, NIR (both photometry
and spectroscopy), UV and radio observations to obtain the best
constraints to what might represent a new type of SN explosion.

Sequence Number: 502266

Title : A search for absorption features in the afterglow of the unusual GRB
130925A
PI: Bellm
Abstract: GRB 130925A produced several emission episodes triggering Swift-BAT,
Fermi-GBM, and MAXI. The extraordinary length of this emission--over
10^4 seconds--would give GRB 130925A one of the highest total
durations ever observed for a gamma-ray burst. While the initial
bursting phase was similar to that of the the relativistic tidal
disruption event Swift J1644+57, starting at 10^4 seconds after the
trigger this event has entered a steady decay phase without new bursts
(www.swift.ac.uk/xrt_curves/00571830/). Its classification is thus
uncertain, as neither the long GRB class nor Swift J1644 provide
direct parallels. Our NuSTAR spectroscopy during the decay phase has
revealed evidence for a broad absorption feature never previously
observed for either GRB afterglows or for tidal disruption events.
Chandra observations will enable searches for lower-energy lines which
may constrain the ionization state of this unprecedented event.

Sequence Number: 502265

Title : GRB130831A: the birth of a magnetar
PI: De Pasquale
Abstract: Follow-up observations by XRT, UVOT, and ground facilities show Swift
GRB130831A to be an interesting and unusual long GRB at z=0.48, with a
bright optical afterglow. The X-ray light curve of this event
(www.swift.ac.uk/xrt_curves/00568849) displays a rare extremely steep
break from a power-law decay of 1.1 to 5 at ~10^5 s. The standard
forward-shock (FS) fireball model cannot explain the steepness of this
break. Instead it is the signature expected from the spin-down
emission of a newly-born magnetar seen before in short GRBs (Rowlinson
et al. 2013), but only once so far in a long GRB (070110, but 130831A
is a far superior example because the break is much later and we have
better coverage at other wavelengths). With the magnetar emission now
gone, we can measure the FS emission at nu > nu_c (with Chandra; it's
too faint now for Swift) to infer the total energy imparted to the
ejecta and have the first ever measurement of the efficiency of a
magnetar as central engine of a long GRB.

Sequence Number: 502264

Title : GRB130831A: the birth of a magnetar
PI: De Pasquale
Abstract: Follow-up observations by XRT, UVOT, and ground facilities show Swift
GRB130831A to be an interesting and unusual long GRB at z=0.48, with a
bright optical afterglow. The X-ray light curve of this event
(www.swift.ac.uk/xrt_curves/00568849) displays a rare extremely steep
break from a power-law decay of 1.1 to 5 at ~10^5 s. The standard
forward-shock (FS) fireball model cannot explain the steepness of this
break. Instead it is the signature expected from the spin-down
emission of a newly-born magnetar seen before in short GRBs (Rowlinson
et al. 2013), but only once so far in a long GRB (070110, but 130831A
is a far superior example because the break is much later and we have
better coverage at other wavelengths). With the magnetar emission now
gone, we can measure the FS emission at nu > nu_c (with Chandra; it's
too faint now for Swift) to infer the total energy imparted to the
ejecta and have the first ever measurement of the efficiency of a
magnetar as central engine of a long GRB.

Sequence Number: 502037

Title : The Energetics of the High-Redshift GRB 130606A
PI: Berger
Abstract: GRB 130606A at z=5.91 is only the fourth burst at such high redshift
with detected X-ray, optical/near-IR, and radio emission. The data
quality across the spectrum exceeds that of all previous events,
thereby providing a unique opportunity to study the energy scale and
local environment of a massive star explosion in the first Gyr after
the Big Bang. This will allow us to compare the progenitors of the
most distant GRBs to their more typical cousins at redshifts of z~1-3.
The energy scale will shed light the the nature of the explosion,
while the local density will track mass loss from the progenitor prior
to its demise, a direct clue to its nature. Of particular interest is
a measurement of jet collimation that will provide a measure of the
true energy release; strong evidence for such a "jet break" requires
an achromatic break from radio to X-rays. We will combine the
requested Chandra observation with extensive radio and optical/near-IR
data to decipher the GRB properties.

Sequence Number: 601099

Title : A direct constraint on the mass of an IMBH candidate in NGC 2276
PI: Roberts
Abstract: Although long predicted and searched for, a population of
intermediate-mass black holes (IMBHs) has yet to be detected in the
local Universe. We have recently published a small sample of luminous
ULXs that behave like IMBHs in the low/hard state (Sutton et al. 2012
MNRAS 423 1154). If they are in that state, we expect to see steady
radio jets; from these we can directly measure the black hole mass
using quasi-simultaneous X-ray & radio observations to place an object
on the fundamental plane (see e.g. Merloni et al. 2003 MNRAS 345
1057). In VLA follow-up of the sample an IMBH candidate in NGC 2276
was shown to sit at the centre of two extended radio lobes. We have
now been awarded European VLBI network (EVN) observations to attempt
to detect its radio core. Here we ask for quasi-simultaneous Chandra
observations, necessary to resolve the IMBH candidate from two nearby
(within ~5") ULXs and provide the X-ray data point that will allow us
to measure the mass of the black hole.

Sequence Number: 702923

Title : The unusual state of Mrk 590
PI: Mathur
Abstract: Seyfert 1 galaxy Mrk 590 is presently in an unusual state. Its X-ray
soft-excess has disappeared, its optical continuum has practically
vanished, its optical broad emission lines have disappeared, and it
shows the presence of a relativistic outflow. Even the narrow emission
lines have changed. All these observations could be related to each
other, but were taken years apart. We have an approved DDT on HST to
check if the UV continuum and UV broad emission lines have also
vanished and we request contemporaneous Chandra DDT to look for the
presence/ absence of the soft-excess. Together they will help
understand the common underlying cause which could be low accretion
rate relative to Eddington. They will also answer some long-standing
questions in AGN physics such as: What is the origin of the
soft-excess? What is the origin of the broad emission line region? Mrk
590 provides us with an unique opportunity find the underlying physics
related to these apparently disparate phenomena.

Sequence Number: 401541

Title : An intermediate-mass black hole candidate in NGC 404
PI: Kaaret
Abstract: Discovery (Reines et al. 2011, Nature, 470, 66) of a massive black
hole (MBH) in a star-forming dwarf galaxy has shed light on the
relation between MBHs and galaxy formation and evolution. Optical
observations of the star-forming dwarf galaxy NGC 404 suggest it hosts
a 4.5E5 solar mass BH. EVLA observations by Nyland et al. 2012
combined with archival Chandra data show a radio/X-ray source
consistent with a ~1E6 solar mass BH. We have approved European VLBI
Network (EVN) observations to image NGC 404 at 5 mas resolution,
enabling us to eliminate alternative interpretations (SNR, star
forming region). We request contemporaneous Chandra observations to
determine the X-ray state of the source. The source is too dim for
Swift and only Chandra will resolve the BH from surrounding diffuse
emission. In 15 ks, we expect 18 counts in the 2-10 keV band enabling
detection of hard X-ray emission from the BH.

Sequence Number: 401540

Title : Chandra observation of the newly discovered transient IGR J18245-2452
PI: Papitto
Abstract: IGR J18245-2452 is a newly discovered X-ray transient located in the
globular cluster M28 (ATel #4925), which showed a thermonuclear type-I
X-ray burst proving its NS accreting nature (ATel #4959). Optical and
radio counterparts have been proposed (ATel #4981,5003) and a
separate Chandra TOO has been approved to check the source location.
We proposea 60 ks Chandra observation with the HRC to check for any
additional close-by sources in the crowded environment of the
cluster, and to study variability of its emission.

Sequence Number: 100095

Title : High Latitude Charge Exchange X-rays from Comet PANSTARRS in the Cold
Polar Solar Wind
PI: Lisse
Abstract: For the 1st time since the 1996 discovery of cometary X-ray emission,
Chandra can characterize the solar wind in the heliosphere AUs above
the ecliptic plane using the very active Comet PANSTARRS (C/2011 L4).
At +83o latitude the comet will encounter the low density, low
ionization temperature polar solar wind, entirely lacking in O+8 ions,
deficient in O+7 ions, and rich in O+6 ions. The Chandra Comet
PANSTARRS observations will also extend the observed regime of CXE
emission to much lower wind densities and temperatures. The polar wind
should produce an ACIS-S spectrum with no OVIII charge exchange lines,
very weak OVII lines, and unusually strong OVI lines. Thus we will use
ACIS to search for weak CXE lines due to highly stripped CNFeMgNeSi
solar wind ions normally dominated by OVII and OVIII at 500-800 eV,
and detect OVI at 0.11 keV using the sensitivity of Chandra's HRC-I
camera to extremely soft x-rays. 3 identical visits are requested to
allow for solar wind variability.

Sequence Number: 100094

Title : High Latitude Charge Exchange X-rays from Comet PANSTARRS in the Cold
Polar Solar Wind
PI: Lisse
Abstract: For the 1st time since the 1996 discovery of cometary X-ray emission,
Chandra can characterize the solar wind in the heliosphere AUs above
the ecliptic plane using the very active Comet PANSTARRS (C/2011 L4).
At +83o latitude the comet will encounter the low density, low
ionization temperature polar solar wind, entirely lacking in O+8 ions,
deficient in O+7 ions, and rich in O+6 ions. The Chandra Comet
PANSTARRS observations will also extend the observed regime of CXE
emission to much lower wind densities and temperatures. The polar wind
should produce an ACIS-S spectrum with no OVIII charge exchange lines,
very weak OVII lines, and unusually strong OVI lines. Thus we will use
ACIS to search for weak CXE lines due to highly stripped CNFeMgNeSi
solar wind ions normally dominated by OVII and OVIII at 500-800 eV,
and detect OVI at 0.11 keV using the sensitivity of Chandra's HRC-I
camera to extremely soft x-rays. 3 identical visits are requested to
allow for solar wind variability.

Sequence Number: 100093

Title : High Latitude Charge Exchange X-rays from Comet PANSTARRS in the Cold
Polar Solar Wind
PI: Lisse
Abstract: For the 1st time since the 1996 discovery of cometary X-ray emission,
Chandra can characterize the solar wind in the heliosphere AUs above
the ecliptic plane using the very active Comet PANSTARRS (C/2011 L4).
At +83o latitude the comet will encounter the low density, low
ionization temperature polar solar wind, entirely lacking in O+8 ions,
deficient in O+7 ions, and rich in O+6 ions. The Chandra Comet
PANSTARRS observations will also extend the observed regime of CXE
emission to much lower wind densities and temperatures. The polar wind
should produce an ACIS-S spectrum with no OVIII charge exchange lines,
very weak OVII lines, and unusually strong OVI lines. Thus we will use
ACIS to search for weak CXE lines due to highly stripped CNFeMgNeSi
solar wind ions normally dominated by OVII and OVIII at 500-800 eV,
and detect OVI at 0.11 keV using the sensitivity of Chandra's HRC-I
camera to extremely soft x-rays. 3 identical visits are requested to
allow for solar wind variability.

Sequence Number: 702922

Title : Confirm the Nuclear Origin of the Post-flare Hard Spectrum from a
Tidal Disruption Event Candidate
PI: Lin
Abstract: Stars approach a SMBH can be tidally disrupted and subsequently
accreted. Such kind of tidal disrupt events (TDEs) provide a unique
way to find and study inactive SMBHs and may also provide an important
mechanism of growing them. Only about twenty such candidates have been
reported. Following-up of such events is important to constrain their
long-term evolution to help to pin down their nature and strengthen
the TDE theory. TDEs show large dynamic ranges on timescales of years,
allowing to search for possible state transition to test whether
accretion onto SMBHs is similar to that in stellar-mass BH X-ray
binaries. We now need an immediate Chandra observation to confirm the
nuclear origin of a post-flare hard spectrum from our TDE candidate
which has very soft spectra at the flare peak.

Sequence Number: 100097

Title : High Latitude Charge Exchange X-rays from Comet PANSTARRS in the Cold
Polar Solar Wind
PI: Lisse
Abstract: For the 1st time since the 1996 discovery of cometary X-ray emission,
Chandra can characterize the solar wind in the heliosphere AUs above
the ecliptic plane using the very active Comet PANSTARRS (C/2011 L4).
At +83o latitude the comet will encounter the low density, low
ionization temperature polar solar wind, entirely lacking in O+8 ions,
deficient in O+7 ions, and rich in O+6 ions. The Chandra Comet
PANSTARRS observations will also extend the observed regime of CXE
emission to much lower wind densities and temperatures. The polar wind
should produce an ACIS-S spectrum with no OVIII charge exchange lines,
very weak OVII lines, and unusually strong OVI lines. Thus we will use
ACIS to search for weak CXE lines due to highly stripped CNFeMgNeSi
solar wind ions normally dominated by OVII and OVIII at 500-800 eV,
and detect OVI at 0.11 keV using the sensitivity of Chandra's HRC-I
camera to extremely soft x-rays. 3 identical visits are requested to
allow for solar wind variability.

Sequence Number: 100096

Title : High Latitude Charge Exchange X-rays from Comet PANSTARRS in the Cold
Polar Solar Wind
PI: Lisse
Abstract: For the 1st time since the 1996 discovery of cometary X-ray emission,
Chandra can characterize the solar wind in the heliosphere AUs above
the ecliptic plane using the very active Comet PANSTARRS (C/2011 L4).
At +83o latitude the comet will encounter the low density, low
ionization temperature polar solar wind, entirely lacking in O+8 ions,
deficient in O+7 ions, and rich in O+6 ions. The Chandra Comet
PANSTARRS observations will also extend the observed regime of CXE
emission to much lower wind densities and temperatures. The polar wind
should produce an ACIS-S spectrum with no OVIII charge exchange lines,
very weak OVII lines, and unusually strong OVI lines. Thus we will use
ACIS to search for weak CXE lines due to highly stripped CNFeMgNeSi
solar wind ions normally dominated by OVII and OVIII at 500-800 eV,
and detect OVI at 0.11 keV using the sensitivity of Chandra's HRC-I
camera to extremely soft x-rays. 3 identical visits are requested to
allow for solar wind variability.

Sequence Number: 100095

Title : High Latitude Charge Exchange X-rays from Comet PANSTARRS in the Cold
Polar Solar Wind
PI: Lisse
Abstract: For the 1st time since the 1996 discovery of cometary X-ray emission,
Chandra can characterize the solar wind in the heliosphere AUs above
the ecliptic plane using the very active Comet PANSTARRS (C/2011 L4).
At +83o latitude the comet will encounter the low density, low
ionization temperature polar solar wind, entirely lacking in O+8 ions,
deficient in O+7 ions, and rich in O+6 ions. The Chandra Comet
PANSTARRS observations will also extend the observed regime of CXE
emission to much lower wind densities and temperatures. The polar wind
should produce an ACIS-S spectrum with no OVIII charge exchange lines,
very weak OVII lines, and unusually strong OVI lines. Thus we will use
ACIS to search for weak CXE lines due to highly stripped CNFeMgNeSi
solar wind ions normally dominated by OVII and OVIII at 500-800 eV,
and detect OVI at 0.11 keV using the sensitivity of Chandra's HRC-I
camera to extremely soft x-rays. 3 identical visits are requested to
allow for solar wind variability.

Sequence Number: 100094

Title : High Latitude Charge Exchange X-rays from Comet PANSTARRS in the Cold
Polar Solar Wind
PI: Lisse
Abstract: For the 1st time since the 1996 discovery of cometary X-ray emission,
Chandra can characterize the solar wind in the heliosphere AUs above
the ecliptic plane using the very active Comet PANSTARRS (C/2011 L4).
At +83o latitude the comet will encounter the low density, low
ionization temperature polar solar wind, entirely lacking in O+8 ions,
deficient in O+7 ions, and rich in O+6 ions. The Chandra Comet
PANSTARRS observations will also extend the observed regime of CXE
emission to much lower wind densities and temperatures. The polar wind
should produce an ACIS-S spectrum with no OVIII charge exchange lines,
very weak OVII lines, and unusually strong OVI lines. Thus we will use
ACIS to search for weak CXE lines due to highly stripped CNFeMgNeSi
solar wind ions normally dominated by OVII and OVIII at 500-800 eV,
and detect OVI at 0.11 keV using the sensitivity of Chandra's HRC-I
camera to extremely soft x-rays. 3 identical visits are requested to
allow for solar wind variability.

Sequence Number: 100093

Title : High Latitude Charge Exchange X-rays from Comet PANSTARRS in the Cold
Polar Solar Wind
PI: Lisse
Abstract: For the 1st time since the 1996 discovery of cometary X-ray emission,
Chandra can characterize the solar wind in the heliosphere AUs above
the ecliptic plane using the very active Comet PANSTARRS (C/2011 L4).
At +83o latitude the comet will encounter the low density, low
ionization temperature polar solar wind, entirely lacking in O+8 ions,
deficient in O+7 ions, and rich in O+6 ions. The Chandra Comet
PANSTARRS observations will also extend the observed regime of CXE
emission to much lower wind densities and temperatures. The polar wind
should produce an ACIS-S spectrum with no OVIII charge exchange lines,
very weak OVII lines, and unusually strong OVI lines. Thus we will use
ACIS to search for weak CXE lines due to highly stripped CNFeMgNeSi
solar wind ions normally dominated by OVII and OVIII at 500-800 eV,
and detect OVI at 0.11 keV using the sensitivity of Chandra's HRC-I
camera to extremely soft x-rays. 3 identical visits are requested to
allow for solar wind variability.

Sequence Number: 901095

Title : Localizing NuSTAR J163433-473838: the First Source Discovered by
NuSTAR
PI: Tomsick
Abstract: A goal of the NuSTAR mission is to study hard X-ray populations in the
Galaxy. While INTEGRAL has carried out a wide survey, uncovering many
new types of interesting and extreme sources (highly energetic PWNe,
new types of HMXBs, etc.), NuSTAR emphasizes going deeper into the
Galactic plane to look for hidden populations. NuSTAR recently found
its first new source, NuSTAR J163433-473838, during an observation of
the Norma spiral arm region. In addition to searching for known
sources in SIMBAD, CSC, etc., we are confident that it is a new source
as Chandra did not detect it during an observation in mid-2011. We are
looking for compact objects in regions with star formation to look for
faint HMXBs that are early in their evolutionary process or perhaps
magnetars or black holes that are expected to be associated with high
mass stars. We are requesting a Chandra observation to localize the
source in order to search for counterparts (e.g., near-IR) to
determine its nature.

Sequence Number: 300318

Title : Understanding the X-ray temperature vs life time dependence of novae
PI: Henze
Abstract: What determines the life time of post-nova outburst supersoft X-ray
sources (SSSs)? A recent fast optical nova in M31 (ATels #4765,4768)
was detected surprisingly early (8 d post-discovery) in a Swift XRT
ToO. An XMM-Newton ToO was granted and unexpectedly revealed a
low-temperature SSS. Later, repeated Swift observations did not detect
the source after only 8 d of activity. This would not only indicate
the fastest SSS evolution of any known nova, it also places the object
well outside recently found correlations between nova parameters, as
only hot novae should evolve fast. However, due to its low-energy
response, Swift could not follow a more gradual decline in X-ray
luminosity and the target is now sun-constrained for XMM-Newton. We
strongly expect to be in agreement with current models and empirical
relations by detecting the nova with Chandra. A non-detection would
severely challenge our understanding of the connections between nova
observables.

Sequence Number: 502032

Title : Investigating the nature of the transient source in M 82
PI: Madej
Abstract: In our Swift X-ray monitoring of M82 we found a new bright transient
which position does not correspond to any of the known sources in this
galaxy. We would like to investigate the nature of this transient
source.

Sequence Number: 200910

Title : Observation of a possible 'orphan' GRB afterglow
PI: Vianello
Abstract: A GRB is highly beamed, while its afterglow is less so. In principle
this should allow to detect orphan afterglows , which has never
happened. The 1.5m MLS telescope of the CRTS discovered a peculiar
transient, which could be such an event. No GRB were detected at or
around that time. An obvious progenitor could be a low-mass star.
However, several co-added MLS images from before does not reveal the
source either, nor do all optical and X-ray surveys. Considering the
prototypical UV Ceti, this flare should have produced a brightening
above 7.5 mags, which would be extremely atypical (Kowalski et al.
2010). Observations with the Palomar 5m telescope (DBSP) and Palomar
1.5m showed no trace of the source (down to ~21st mag) 1 day after,
and 10 days later no photons were detected by Swift/XRT. This is
consistent with a typical afterglow with a power-law decay with
alpha=-1. Confirming the nature of this source would be extremely
valuable for our understanding of GRB afterglows.

Sequence Number: 300317

Title : Nova Mon 2012 as a luminous supersoft X-ray source
PI: Orio
Abstract: Chandra gratings observations of novae in outburst have constrained
the models of accreting and hydrogen burning white dwarfs (novae and
the possible type Ia progenitors) and are allowing unprecedented
discoveries in the nova physics. The supersoft X-ray phase of novae
isthe only way to catch a glimpse of the white dwarf itself, when
hydrogen burning is still ongoing but only a thin atmosphere sits on
top of it. The proposer of this observations has assessed the
theoretical prediction that the white dwarf effective temperature is a
proxy for the white dwarf mass and this has opened many new
possibilities (see Orio 2012, aeXiv 1210.4331). Some novae also show
supersoft emission because of very strong emission lines in the
ejecta, revealing a whole new physics (see also Orio 2012).This nova
is exceptional, it was only one of three detected with the Fermi LAT,
and extremely high energy phenomena seem to happen in the ejecta
(possibly because of large amounts of circumstellar material).

Sequence Number: 702920

Title : Sw1644+57: a relativistic jet that switched on and is now switching
off
PI: Tanvir
Abstract: Sw-J1644+57 was detected as a long-lived gamma-ray outburst in Mar
2011. Its unique H-E properties and location in the nucleus of a small
galaxy at z=0.35, suggested it was due to the tidal disruption of a
star by a 1-10 million Mo black-hole producing a relativistic jet. The
super-Eddington luminosity is understood by the jet pointing towards
us. Subsequent monitoring has shown the emission to decline roughly at
the expected -5/3 power-law for TDE fall-back, till a few weeks ago
when it abruptly "switched off". Our recent XMM data fixes the decline
to be a factor ~100 over only ~60d. Such a rapid shut-down of
accretion (~t^-25) seems implausible, so likely it represents the jet
launching mechanism turning off. We request a CXO observation, several
weeks after the XMM visit, to to establish whether the flux continues
to decline, or stabilises at a low level (eg. due to emission directly
from the accretion disk), thus shedding light on the poorly understood
process of jet production.

Sequence Number: 300316

Title : Grating Spectroscopy of early hard X-ray emission in Nova Mon 2012
PI: Ness
Abstract: The nova Mon 2012 of Aug9 2012 (CBET 3202) has fortuitously been
observed with initial gamma ray emission >100MeV before it was
discovered in optical. Optical observations show similarities with the
ONe nova V382 Vel (1999) (ATel4310). Recent Swift observations yield a
surprisingly bright hard spectrum of a collisional plasma with 3keV
temperature and NH=3E22 (ATel4321), ~10 times the inferred
interstellar value. For these types of spectra we have shown to have
robust model techniques yielding abundances, velocity structure and
ionization state. The only nova grating spectrum of early hard
emission is of RS Oph, but without a giant companion, the origin in
Mon 2012 must be different. Constraining the nova ejecta with a
grating spectrum will illuminate on possible mechanisms for the
production of the initial >100 MeV gamma-rays that may in fact be
general to all high velocity ejection events.

Sequence Number: 502021

Title : The outflow geometry of the short GRB 120804A
PI: Troja
Abstract: The angular size of the GRB outflow is a key ingredient in determining
the total burst energy release and the true events rate. These
parameters are a crucial test for any progenitor and central engine
model. However, despite years of intense follow-up observations, the
degree of collimation of short GRBs still remains a missing piece of
information. Only a few short GRBs display a long-lived, and
relatively bright afterglow, detected in the X-ray, optical, and radio
bands. In these cases meaningful constraints on the jet opening angle
can be placed. We therefore propose to observe the afterglow of
GRB120804A with Chandra a few days after the explosion in order to
search for a jet-break, which is a clean diagnostic tool for
constraining the outflow geometry.

Sequence Number: 502020

Title : 1E 2259+586: Detecting Particle Outflow from an Active Magnetar
PI: Kaspi
Abstract: Magnetars are a class of neutron stars for which the majority of the
radiative output is believed to be powered by the decay of large
(~10E14-10E15 G) magnetic fields. On 2012 April 28, as seen in our
regular Swift monitoring observations, one well-known magnetar, 1E
2259+586, in SNR CTB109, entered a period of enhanced flux (ATel.
4080),and simultaneously suffered a timing anomaly. One proposed
mechanism to explain such outbursts is particle outflow (Thompson et
al. 2000) where large amounts of plasma are advected from the magnetar
at relativistic speeds. This suggests the possibility of a transient
outflow that could result in a jet-like or nebular X-ray structure. A
detection of a transient, small-scale X-ray nebula would be strong
evidence in favor of this model.

Sequence Number: 501800

Title : Disclosing the position of the naked-eye-alike GRB120624B's afterglow
PI: Campana
Abstract: GRB120624B was detected by Swift and Fermi-LAT at very high energies,
but was Moon constrained for Swift follow-up. It is an extremely
bright burst, placing it in the brightest 1% of Swift and Fermi
bursts, only a factor of 2 fainter than the naked-eye GRB080319B. The
lightcurve shows much sub-structure, with hints of periodic behaviour.
A late 10ks Swift XRT observation located an X-ray afterglow candidate
at F_X~8e-14 ergs/s/cm^2. Such a faint X-ray afterglow is very
unusual. Bright bursts such as this one would typically be much
brighter at these times, by factor of ~10 (e.g. Gehrels et al. 2008).
Two deep NIR observations taken with VLT/HAWKI located a candidate,
but it is unusually faint too, and we cannot rule out an unrelated
source. This NIR source is not coincident with the X-ray source. Given
the unique nature of GRB120624B which appears unlike any previously
observed Swift burst, and the significant interest in tracking rare
Fermi-LAT bursts, we request a rapid Chandra ToO.

Sequence Number: 401435

Title : Unveiling an intermediate-mass black hole in the spiral galaxy NGC
4088
PI: Mezcua
Abstract: We have recently detected compact radio emission from the ULX N4088-X1
using the EVN at 1.6 GHz consistent with steady jets from a black
hole. A series of Swift observations obtained around the same time
found the spectrum to be very hard, consistent with the low/hard state
when steady jets are expected. The radio and X-ray luminosities are
consistent with a black hole mass of ~10,000 Msun, however to
accurately measure the mass using the fundamental plane of accreting
black holes we need observations at 5 GHz. To this end we have been
awarded additional 5 GHz EVN observations in early June, and we
request a simultaneous Chandra DDT observation to accurately measure
the mass and confirm the association between the X-ray and radio
emission (for which a sub-arcsecond X-ray position is needed). If
confirmed, this would be the first detection of steady jets from an
intermediate mass black hole (IMBH), and would provide the first
accurate mass measurement of an IMBH.

Sequence Number: 401434

Title : An HETGS Observation of Extreme Activity in 4U 1630-47
PI: Neilsen
Abstract: The black hole candidate 4U 1630-47 recently entered an extremely
bright, active state in its outburst, with X-ray flux varying by a
factor of 4 on timescales of 1 day (mean flux ~0.3 Crab) and strong
hard X-ray emission (as seen by MAXI, Swift/BAT). Our recent
HETG/Suzaku observations of the source in a soft, steady state at 50%
lower flux revealed deep absorption lines from an extremely massive
disk wind. The new active state represents an excellent opportunity to
study how such massive winds respond to strong X-ray variability and
state changes, which have never been probed in 4U 1630-47. Our
proposed 20 ks CC-mode observation will reveal any long- and
short-term modulation in the massive disk wind, while additionally
providing simultaneous probes of any rapid X-ray variability and
changes in the X-ray continuum.

Sequence Number: 401430

Title : Swift J1753.5-0127 in the soft state: signatures of an outflowing
wind
PI: Soleri
Abstract: Miller et al. (2006, Nat., 441, 953) detected absorptions lines in the
Chandra spectra of the black hole GRO J1655-40 in the soft state,
associated with a disc wind. Ponti et al. (2012, MNRAS, 422, L11)
showed that disc winds are common among black holes in the soft state
(but see Neilsen & Homan 2012, ApJ, 750, 27); these winds are more
easily detected in nearly edge-on sources. Swift J1753.5-0127 is a
black hole candidate which has been active since May 2005 and it is
now entering the soft state (Atel #4056). From a fit to a broad Fe
line, Hiemstra et al. (2009, MNRAS, 394, 2080) found that the system's
inclination is high, although no dips or eclipses were observed. We
ask for a 20 ks Chandra observation to detect signatures of a disc
wind, set constraints on the driving mechanisms (which are still
unclear) and estimate the mass loss in the wind. If we also detect the
broad Fe line we can compare its properties to those in the hard
state.

Sequence Number: 300312

Title : Nova LMC 2012 at high spectral resolution
PI: Drake
Abstract: Nova LMC 2012 is the first X-ray bright nova easily accessible to
Chandra gratings to have occurred in Swift Era. Unlike the highly
uncertain distances of novae in the Galaxy, the LMC is at known
distance and nova luminosities can be precisely measured.
Spectroscopic evidence and the fast evolution of the event suggests it
might be a recurrent nova. High resolution X-ray spectra will allow
diagnosis of the radiatively-driven outflow through line profiles, and
will provide a chemical composition snapshot of the supersoft source
envelope. Existing grating observations of novae have shown a diverse
array of spectral features, but recently a pattern has emerged in
which emission lines are stronger for smaller inclination angles. A
Chandra LETG spectrum will provide key insights into the emission
geometry and will help diagnose the processes underlying the
radiatively-driven outflow in what will be a close to Eddington
Luminosity source.

Sequence Number: 401429

Title : An HETGS Observation of the Transient MAXI J1305-704
PI: Miller
Abstract: MAXI J1305-704 is a new X-ray transient, which has come up to a flux
level of 0.07 Crab (see ATEL 4044) and appears to be in a fairly soft
state. Dips have been observed in the X-ray flux, indicating a high
inclination, and possibly also a very short orbital period. This
represents an excellent chance to study the disk atmosphere in this
source, and connections to disk winds. Importantly, the line of sight
column density forthis source is low (1-2 E+21) and will enable
sensitive spectroscopy across the full HETGS band. A 30 ksec
observation of MAXI J1305-704 will yield approximately 1 million
photons in the MEG and HEG, at current flux levels.

Sequence Number: 501797

Title : Supernova PTF 11qcj: first discovery of a radio luminous Ibn
supernova
PI: Corsi
Abstract: PTF 11qcj is a Ibn supernova (SN) discovered by PTF. Its spectra show
He emission lines, related to the interaction with a He-rich dense
shell. Only 4 SNe like this are known, the most famous is SN 2006jc.
11qcj is the only known case of a radio-loud Ibn SN. The Chandra X-ray
light curve of 2006jc supported the He-shell scenario, showing a flux
increase of a factor of 5 in the first 4 months after discovery,
different from the typical power-law decay of X-ray SNe interacting
with a circum-stellar wind. The two Chandra observations of 11qcj
reveal an X-ray luminosity 5x that of 2006jc (at a similar epoch).
Based on the template X-ray behavior of 2006jc, and on the radio
observations we collected so far for 11qcj (the radio emission seems
to track the X-ray behavior), we expect that 11qcj X-ray light curve
is now decreasing. We ask to re-observe 11qcj with Chandra before it
becomes too faint, so as to measure the X-ray light curve FWHM and
constrain the thickness of the dense shell.

Sequence Number: 501796

Title : X-ray followup of type IIP SN 2011ja
PI: Ray
Abstract: We request a Chandra DDT observation of this IIP SN for 60 ks. In our
Chandra observation of 2012Jan10 (39.45 ks exposure, ObsID 13791) we
have detected the SN with 135 counts (0.3-3 keV, background
subtracted) in ACIS-S. A fixed-abs APEC model gives a good fit (kT=
1.6 +- 0.1 KeV and Flux (0.5-2 keV) = 8.8e-15 cgs, with excess
emission at 1.33 keV. The NEI model with free abundance of Mg XI
forbidden line at 1.334 keV can explain the line for a 3.69+/-1.37
fold overabundance of Mg (3 sigma). Both thermal & non thermal Inverse
Compton models can be conclusively ruled out. The line contains 21
counts. As the SN ages the forbidden line should decrease in strength
as gas comes into ionization equilibrium. Chandra observation will
confirm and model the existence of the Mg line and its evolution and
determine the SN ejecta structure. Stacked exposures can detect
further element lines. We have observed it with GMRT (ATel 3899).

Sequence Number: 200830

Title : X-ray irradiation and evaporation of a super-Earth exoplanet
PI: Wheatley
Abstract: The recent discovery that the super-Earth exoplanet 55 Cnc e transits
its 6th mag star provides the exciting opportunity to study the upper
atmosphere of a super-Earth for the first time. Our team has secured
HST DDT with the aim of searching for hydrogen escaping the planet (by
measuring absorption in Ly-alpha through two transits). The planet
density suggests that it may be composed largely of water, in which
case hydrogen evaporation may be expected from a photo-disassociating
super-critical ocean. We propose Chandra observations to measure the
X-ray flux of the host star at the time of both HST observations (on
Mar 7 and Apr 5). Exoplanet evaporation is thought to be driven by
X-ray irradiation, and combined X-ray/UV measurements are required to
measure the mass loss rate and determine the evaporation efficiency.
By measuring X-ray irradiation and the resulting evaporation through
two transits we can begin to study the response of a super-Earth
atmosphere to varying irradiation.

Sequence Number: 200829

Title : X-ray irradiation and evaporation of a super-Earth exoplanet
PI: Wheatley
Abstract: The recent discovery that the super-Earth exoplanet 55 Cnc e transits
its 6th mag star provides the exciting opportunity to study the upper
atmosphere of a super-Earth for the first time. Our team has secured
HST DDT with the aim of searching for hydrogen escaping the planet (by
measuring absorption in Ly-alpha through two transits). The planet
density suggests that it may be composed largely of water, in which
case hydrogen evaporation may be expected from a photo-disassociating
super-critical ocean. We propose Chandra observations to measure the
X-ray flux of the host star at the time of both HST observations (on
Mar 7 and Apr 5). Exoplanet evaporation is thought to be driven by
X-ray irradiation, and combined X-ray/UV measurements are required to
measure the mass loss rate and determine the evaporation efficiency.
By measuring X-ray irradiation and the resulting evaporation through
two transits we can begin to study the response of a super-Earth
atmosphere to varying irradiation.

Sequence Number: 501794

Title : Supernova PTF 11qcj: first discovery of a radio luminous Ibn
supernova
PI: Corsi
Abstract: PTF 11qcj is a Ic supernova (SN) discovered by PTF. Its spectra show
He emission lines, related to the interaction with a He-rich dense
shell. Only 4 SNe like this (called type Ibn SNe), are known. The
prototype is the famous SN 2006jc. The exceptional thing about 11qcj
is that it is radio loud: only this one case of a radio-loud Ibn SN is
know. The Chandra X-ray light curve of 2006jc supported the He-shell
scenario, showing a flux increase of a factor of 5 in the first 4
months after discovery, different from the typical power-law decay of
X-ray SNe interacting with a circum-stellar wind. The Chandra
observation of 11qcj at about 80d since discovery, reveals an X-ray
luminosity 5x that of 2006jc (at a similar epoch). Aim of this
proposal is to track the evolution of 11qcj X-ray light curve, so as
to determine its peak flux and timescale, that are crucial for the
broad-band modeling (currently, we are carrying out an extensive
follow-up campaign in radio, optical, and infrared).

Sequence Number: 501793

Title : Supernova PTF 11qcj: first discovery of a radio luminous Ic SN
interacting with an He shell?
PI: Corsi
Abstract: PTF 11qcj is a Ic supernova (SN) discovered by PTF on 2011 Oct 23. Its
spectrum on day 34 shows He I emission lines which are very rare,
suggesting this a Ibn: a Ic SN interacting with a He-rich cold dense
shell (CDS). Only 4 Ibn SNe are known, the best studied prototype is
the famous SN 2006jc. The Chandra X-ray light curve of 2006jc
supported the CDS scenario, showing a flux increase of a factor of 5
in 4 months, very different from the power-law decay of X-ray SNe
interacting with a circum-stellar wind material (CSM). However, SN
2006jc was undetected in radio. PTF 11qcj may represent the first
discovery of a radio luminous Ibn: our EVLA observations at 40 d
reveal it is 100x more luminous than 2006jc in radio. This suggests
strong CSM interaction which, based on 2006jc, makes a detection with
Chandra likely. We thus request a Chandra observation: measuring the
X-ray luminosity of this event will allow us to constrain the density
of the CDS and confirm the Ibn nature of 11qcj.

Sequence Number: 401427

Title : Chandra Astrometry of a New ULX in NGC 891
PI: Hodges-Kluck
Abstract: A 08/2011 XMM observation of NGC 891 shows a bright (L_X ~ 2E40 erg/s;
F_X ~ 1E-12 erg/s/cm^2) new ULX near the disk. It is absent in
archival X-ray observations. Variability in Swift monitoring and the
absence of bright optical or radio counterparts rule out a SN. As a
bright ULX that recently "turned on" and whose spectrum indicates a
hot (kT ~ 1 keV) disk, the source may be an extreme example of
super-Eddington (5-50 L_Edd) accretion. Deep archival HST images
reveal a potential counterpart--a star cluster--within the 2" X-ray
error circle, but it is only 0.5" across. A better position is a
prerequisite for proposing deep spectroscopic follow-up, and the lack
of radio or optical counterparts in follow-up observations makes CXO
the only option. We expect an ACIS-S count rate of 0.07-0.2 cts/s, and
request 2 ks of DDT time to obtain 150-400 cts, thereby sampling the
PSF extremely well. Although a snapshot is susceptible to flaring, the
ULX is extremely bright.

Sequence Number: 501792

Title : Studying the physics of outbursts in the Westerlund 1 transient
magnetar laboratory
PI: Israel
Abstract: CXOUJ1647 is a transient magnetar which is currently in outburst
(September 2011). The previous one occurred in 2006. Preliminary
analysis of the timing and spectral parameters of the new outburst
suggest a different behaviour with respect to the 2006 event. The main
aims of the DDT request are: the detection of Pdot variations and
therefore of variations of the B-field topology during the 2
outbursts, and monitoring both the spectral and timing evolution in
order to compare them with those of 2006. In particular, the way the
parameters of the two events evolve will allow us to answer to the
following questions: Are all magnetar outbursts originated by large
displacements and/or cracks of the neutron star surface? Are the hot
spots originated by the outburst always occurring on the same places ?
We note that Chandra is currently the only mission able to point to
the source and to achieve a phase accuracy large enough for keeping
the coherency until the next visibility window.

Sequence Number: 501791

Title : Chandra Observations of the Nearest Type Ia SN in 25 Years
PI: Hughes
Abstract: No SN Ia has been detected in the X-ray band during outburst. The most
careful limits have been set using a 20 ks Chandra observation of SN
2002bo in NGC 3190 (22 Mpc), which was observed 9.3 days after
explosion (Hughes et al. 2007), resulting in limits on the
circumstellar medium (CSM) of w = \dot M/ v_w < 1.2E15 g/cm, assuming
a wind density profile \rho_w = \dot M/(4\pi v_w r^2). This limit is
comparable to the limits set by the nondetection of H\alpha flux from
SN 1994D and SN 2001el, although they are less constraining than
limits set in the radio (Panagia et al. 2006). X-ray constraints are
based on direct calculation of the expected emission using
well-understood physics (i.e., bremsstrahlung emission,
Comptonization), while radio limits are subject to large systematic
uncertainties because the efficiency for generating synchrotron
radiation in the shocked wind and ejecta is not known. We will work
with Nikolai Chugai to model and intepret the results.

Sequence Number: 401425

Title : Chandra spectroscopy of the X-ray spectrum of the newly discovered
accreting millisecond pulsar IGR J17498-2921
PI: Di Salvo
Abstract: Papitto et al. (2011, ATel #3556) reported the discovery of a coherent
pulsed signal from the hard X-ray transient IGR J17498-2921 (Gibaud et
al. 2011, ATel #3551) at a frequency of 401 Hz, very similar to the
spin frequency of the first discovered Accreting Millisecond Pulsar
(AMSP) SAX J1808.4-3658. Taking advantage from the reported position
of the source (ATels #3558, #3559) we propose to observe this source
with Chandra/HETG in order to perform X-ray spectroscopy of the X-ray
spectrum of this interesting source and to get invaluable information
on the innermost emitting region. The PCA spectrum shows evidence of a
strong and broad iron emission line at 6.4 keV (sigma = 0.8 keV).
Chandra will be able to confirm that the line is produced at the inner
accretion disc. In this case, fitting with self-consistent reflection
models will give important information on the position of the
magnetospheric radius and on the neutron star magnetic field.

Sequence Number: 401425

Title : Chandra spectroscopy of the X-ray spectrum of the newly discovered
accreting millisecond pulsar IGR J17498-2921
PI: Di Salvo
Abstract: Papitto et al. (2011, ATel #3556) reported the discovery of a coherent
pulsed signal from the hard X-ray transient IGR J17498-2921 (Gibaud et
al. 2011, ATel #3551) at a frequency of 401 Hz, very similar to the
spin frequency of the first discovered Accreting Millisecond Pulsar
(AMSP) SAX J1808.4-3658. Taking advantage from the reported position
of the source (ATels #3558, #3559) we propose to observe this source
with Chandra/HETG in order to perform X-ray spectroscopy of the X-ray
spectrum of this interesting source and to get invaluable information
on the innermost emitting region. The PCA spectrum shows evidence of a
strong and broad iron emission line at 6.4 keV (sigma = 0.8 keV).
Chandra will be able to confirm that the line is produced at the inner
accretion disc. In this case, fitting with self-consistent reflection
models will give important information on the position of the
magnetospheric radius and on the neutron star magnetic field.

Sequence Number: 501789

Title : Is Swift J1834.9-0846 a magnetar related to SNR W41 and HESS
J1834-087?
PI: Kargaltsev
Abstract: J1834.9-0846 triggered the Swift/BAT and the Fermi/GBM on August 7,
2011. Although an SGR-like event was detected in both cases, a spin
period has not yet been found. Our ToO with RXTE will take place on
August 9. We observed the field with Chandra (Misanovic et al. 2010),
searching for a counterpart to an unidentified TeV source HESS
J1834-087 inside SNR W41. We found a point source, CXOU
J183434.9-084443, and offset extended emission. We re-examined these
Chandra (and archival XMM) data and found no point source at the XRT
position of J1834.9-0846, which, however, falls within the extended
structure seen in the Chandra and XMM images. We request 15ks with
ACIS-S to measure the spectrum of the new source, look for possible
compact PWN and pulsations, and perform phase-resolved spectroscopy
and energy-resolved timing. The Chandra data will be jointly analyzed
with the existing HESS and Fermi data. We will use 1/8 subarray to
probe periods as short as 0.4 s.

Sequence Number: 501788

Title : Resolving the mystery of GRB 110709B
PI: Levan
Abstract: We recently observed GRB110709B under our c12 program. This burst was
both very dark (betaOX < -0.4), and unusual in triggering Swift/BAT
twice (separated by ~15 mins). This could indicate a high-z GRB, a
gravitationally lensed burst, or of (another) novel mechanism for GRB
production. Our CXO imaging showed two objects within or close to the
XRT error circle: the 1st (1.2" from XRT centroid) coincides with a
brightening radio source, presumed to be the GRB afterglow; the 2nd
lies at 2.7", and has near identical brightness. The second object may
also be associated with an optical source (which shows weak archival
evidence for variability), but the X/O offset is surprisingly large
(~0.8"). A second CXO visit to search for variability would greatly
clarify this situation. Is the 2nd source simply a chance foreground
object? Does the 1st source behave like a conventional X-ray
afterglow? The major followup devoted to this most unusual GRB makes a
strong case for another visit.

Sequence Number: 501567

Title : Determination of the true nature of Swift J1822.3-1606
PI: Kouveliotou
Abstract: Swift J1822.3-1606 was detected with the BAT during a ground search of
the data; it also triggered the Fermi/GBM when it emitted a series of
~5 Soft Gamma Repeater like X-ray bursts, each one lasting ~ 5 ms. We
observed the persistent emission of the source with the RXTE/PCA and
confirmed the pulse period of 8.4377585 s. Moreover, we determined a
very high pulsed fraction of the signal of at least 41%. This pulsed
fraction is highly unlikely for an SGR. The source could well be
another Swift J1626.6-5156 (most likely a Be-X-ray binary) or
alternatively, another rotation powered pulsar like PSR
J1846−0258, which was detected to emit SGR-like bursts. The
latter option was the first of its kind linking high B-field pulsars
to SGRs. We are seeking CXO/HRC observations of Swift J1822.3-1606 to
determine the most accurate source location, which will enable us to
identify the source counterpart in this congested region. The current
positional accuracy with Swift XRT is 3.5".

Sequence Number: 702582

Title : Swift J2058+0516: A Second Prompt Relativistic Outflow from a Massive
Black Hole?
PI: Cenko
Abstract: The recent discovery of the transient source Swift J1644 has revealed
a potential new class of high-energy outbursts. Like long-duration
gamma-ray bursts, these sources exhibit a prompt, dramatic energy
release which drives a relativistic outflow. However, the central
engine powering these events is the massive black hole at the center
of a normal galaxy. More recently, Swift has discovered another
high-energy transient, Swift J2058, with broadly similar high-energy
properties. Within the XRT localization (1.7" radius), we have
identified the likely optical counterpart as an absorption line galaxy
at z=1.185. At this redshift, the X-ray luminosity (4e47 erg/s) and
X-ray-to-optical flux ratio (12,000:1) are essentially identical to
that observed from Swift J1644. Here we request HRC-I observations of
Swift J2058 to a) provide precise astrometry (to establish or refute a
nuclear origin), and b) measure the variability time scale (to
constrain the mass of the accreting source).

Sequence Number: 401300

Title : Which M15 Source Is Now in Outburst?
PI: Sivakoff
Abstract: On May 16, MAXI detected an X-ray burst from the globular cluster M15.
Today (5/18) Swift confirmed that either the edge-on ADC source AC 211
or the ultracompact (22-min period) M15 X-2 is flaring (L~1.3E37). It
is unlikely that AC 211 is responsible as one does not expect to see
bursts from ADC sources. The standard paradigm for ultracompact XRBs
like M15 X-2 is that they "should" show stable mass transfer. The few
Chandra observations of M15 X-2 have not showed significant
variations, but today's measured luminosity was 10 times that
typically measured. The 17-minute ultracompact XRB in NGC 1851 has
shown variability by factors of >10 (Maccarone et al. 2010, MNRAS,
406, 2087), a behavior that remains unexplained. Determining that a
second ultracompact exhibits large variations would significantly
challenge the standard paradigm for accretion in ultracompact XRBs.

Sequence Number: 501563

Title : Confirmation of a New Pulsar Wind Nebula
PI: Miller
Abstract: We have recently discovered an extended source with dual ring-like
structure in a shallow Swift image in the Galactic Plane. The
structure is strongly suggestive of a pulsar wind nebula. A known B
star is plausibly associated with the extended source, which means
that the neutron star could be in a binary, and that we could capture
an image of a very young X-ray binary that will eventually become a
double neutron-star system. A short Chandra exposure of just 5 ksec
will be sufficient to confirm the structures suggested by the Swift
image, to obtain a spectrum with approximately 4000 photons, and to
enable multi-wavelength follow-up observations in the near future.

Sequence Number: 702581

Title : Chandra Follow-up of an Exceptional GALEX+PS1 Tidal Disruption Event
Candidate
PI: Gezari
Abstract: We propose for a DDT observation of a candidate tidal disruption event
(TDE) discovered in coordinated UV GALEX and optical Pan-STARRS1 (PS1)
observations. The long-lasting blue color (NUV-r < -1.2) during the
slow decay of the flare over 10 months of GALEX+PS1 monitoring is
unlike any known supernova behavior, and is consistent with the hot
blackbody emission and t^(-5/3) luminosity decay of a TDE. X-ray
observations are critical for determining the broadband SED of the
flare, which is theoretically expected to peak in the soft X-rays.
This flare would have satisfied our Chandra Cycle 11 TOO criteria when
it was discovered in 2010 June, however the first optical spectrum
taken on 2010 June 16 detected an isolated broad emission line that
was misidentified as Mg II at z=0.96. A later spectrum taken on 2011
April 7 revealed absorption features from the host galaxy at z=0.170,
indicating that the broad feature was in fact He II, a high ionization
line associated with TDEs!

Sequence Number: 401297

Title : Probing the neutron star crust of the new transiently accreting 11 Hz
X-ray pulsar in the globular cluster Terzan 5
PI: Degenaar
Abstract: A new bright transiently accreting neutron star was discovered in
Terzan 5 in 2010 October. We obtained a Chandra DDT observation in
February, ~2 months after the end of the outburst, and found the
neutron star a factor ~4 hotter than measured in archival Chandra data
(Degenaar & Wijnands 2011a,b). This indicates that the crust was
severely heated during outburst and that it is possible to observe the
crust cooling curve of this source. However, our target likely cools
considerably faster than previous studied sources, because the short
(~2 months) outburst duration only heated the outer layers of the
neutron star crust (see webpage specified below), which loose the
deposited heat already within months. We request a Chandra DDT
observation to further monitor the cooling curve and put important new
constraints on the neutron star crust: the slope of the cooling curve
directly measures the heat flux in the outer crust, hence the amount
and distribution of heat sources.

Sequence Number: 200735

Title : Hot wind and accretion in TW Hya
PI: Guenther
Abstract: We have recently discovered variability in X-ray indicators of
accretion in the CTTS TW Hya. We seek to use this to understand the
physics of accretion in our upcoming HST observations. We have been
granted 10 HST orbits and 15 CRIRES pointings to monitor the C IV 155
nm doublet and the He I 1083 nm line in TW Hya, the closest CTTS, to
correlate i) the hot wind ii) the cool wind iii) the photometric
period iv) the accretion. In existing HETGS data of TW Hya we see
variability in emission lines from the accretion shock on the star.
However, the densities in Ne IX and O VII indicate that today's shock
models are incomplete. A hot wind is the most promising candidate for
this missing component. Our HST observations will characterize the
wind and we ask for 20 ks Chandra time with LETGS/ACIS simultaneous to
HST to determine the state of accretion. The high effective area of
LETGS/ACIS gives > 100 counts in the O VII and Ne IX triplets, so we
can measure the density and temperature.

Sequence Number: 401295

Title : Searching for the pulsar powering the new TeV binary HESS J0632+057
PI: Torres
Abstract: We request 50 ks Chandra time to check for the existence of X-ray
pulsations from HESS J0632+057. The latter is associated with XMMU
J063259.3+054801 / Be star MWC 148 and has shown a recent increase in
X-ray activity, based on Swift-XRT monitoring (ATEL #3152). We have
used this and previous Swift observations (Falcone et al. 2010, ApJ
708, L52) to positively evaluate the Chandra visibility. HESS
J0632+057 was recently discovered (Aharonian et al. 2007, A&A, 469,
L1), and proposed to be a member of just a handle of such binaries
that emit in gamma-rays. Knowing about its composition is essential
for modeling (e.g., Mirabel 2006, Science 1759). Search for pulsations
from gamma-ray binaries with Chandra have provided the most stringent
upper limits yet (Rea et al. 2010, MNRAS 405, 2206), and its detection
would be a breakthrough for the understanding of these systems.

Sequence Number: 401293

Title : Observing the crust cooling in the 11 Hz accreting pulsar in the
globular cluster Terzan 5
PI: Wijnands
Abstract: We have intensively studied the crust cooling of accreting neutron
stars. We have focused on systems with outbursts lasting years to
decades for which observing the crust cooling is most feasible.
However, as already suggested in Brown et al. 1998 (see the link given
in the TOO Trigger criteria section) crust cooling might also be
observable for systems which have a low quiescent temperature and very
bright but short (weeks/months) outbursts. A recent new transient in
Terzan 5 reached ~1E38 erg/s and its outburst lasted at most a few
months. Combined with its very low quiescent temperature (Degenaar &
Wijnands 2011) this source is an ideal target to test this and to
provide valuable input to any crust-cooling model. Adding this source
to our sample will also be very important to understand the observed
differences between sources and whether this is related to their
different outburst properties and further put constraints on the
properties (ie the crust) of accreting neutron stars.

Sequence Number: 401292

Title : Measuring the Spin of the Black Hole Cgynus X-1, Phase 2
PI: McClintock
Abstract: We are about to submit a paper to Science on the near-maximal spin
(a/M>0.97) of Cyg X-1 [1]. This premier result is largely based on two
DDT Chandra (plus RXTE) spectra obtained last July, two weeks after
Cyg X-1 entered its soft state on 7 July. For these observations, the
Compton component was relatively strong ("scattered fraction" f=34%),
well above the established limit of reliability for our spin method,
which is f=25% [1]. In mid-October, Cyg X-1 entered a "supersoft"
state [1], and we now propose to obtain one additional Chandra
observation (HETG; TE mode; 12 ks) in order to secure our result. We
expect to obtain a Compton-weak spectrum with f<25% (like our 1996
ASCA/RXTE spectrum with f=24%) [1]. To date, our group has measured
the spins of 9 black holes, and this result for Cyg X-1 is distinctly
our most important and exciting [2]. REFERENCES: [1]
https://www.cfa.harvard.edu/~lgou/cygx1/cygx1.html [2]
http://arxiv.org/abs/0909.0169 AND http://arxiv.org/abs/1004.3558

Sequence Number: 501549

Title : Unveiling the nature of cyclic behavior in the period evolution of the
Anomalous X ray Pulsar XTE j1810-197
PI: Perna
Abstract: The goal of our analysis is to probe a possible long term (5 yr)
free-body precession of this neutron star for which we found several
indications based on a non-phase-connected timing analysis. Although
only 3 NS up to now have shown indication of precession, such evidence
strongly challenges our current understanding of the NS interior. The
standard picture of the outer core, in which superfluid neutrons
coexist with type II superconducting protons, requires revision. One
possibility is that protons are type I which would imply a significant
revision of our picture of the physical conditions in the NS core.
Another possibility is that the neutrons are normal in the outer core
which again affects our understanding of the physical state of NSs
core. The presence of long period modulation can shed light on the
physical properties of NS and thus help constraining its equation of
state

Sequence Number: 600982

Title : An Unusual Outburst from the Nucleus of the Quiescent Galaxy NGC 1589
PI: Filippenko
Abstract: As part of the Lick Observatory Supernova Search (LOSS), we have
recently identified an unusual optical outburst from the nucleus
(within 0.05";, or 10 pc in projection) of the nearby (d ~ 50 Mpc)
spiral (S0/a) galaxy NGC 1589. Over a decade of photometric monitoring
with LOSS, together with archival spectroscopy from the CfA Redshift
Survey, suggest the galaxy does not harbor an active galactic nucleus.
Likewise, the bright observed X-ray emission and complex H-alpha
emission profile do not appear to resemble any known Type II
supernova. We therefore believe this transient source (dubbed
NGC1589-OT) represents the most viable candidate for a tidal
disruption flare (TDF) ever discovered in real time. Here we request a
10 ks Chandra/ACIS DD observation to accurately constrain the X-ray
spectral properties (power-law vs. thermal) and environment (n_H) of
this unique, fascinating source. In a separate proposal, we are also
requesting HST time to get a UV spectrum of it.

Sequence Number: 501548

Title : Monitoring of the Crab Nebula
PI: Weisskopf
Abstract: Subsequent to the detection of a gamma ray flare in September, Chandra
has been used to monitor the structure and spectrum of the Crab
Nebula. This flare was first detected by AGILE (ATEL 2855)and had a
timescale of days. The event was also seen with the Fermi Satellite.
These S/C have also observed flaring at other times and with longer
timescales. The Sept. event has received international attention and
it appears that the flaring is not directly associated with the
pulsar, but with the nebular flux. The timescale indicates an emitting
region as small as 0.5-1.0 arcsec at two kpc. Chandra has shown that
there are many features of this scale in the nebula and that they are
constantly changing. It is essential that a viable baseline be
established in order to obtain useful information from future
observations triggered by another flare. We propose a series of
monitoring observations.

Sequence Number: 501547

Title : Monitoring of the Crab Nebula
PI: Weisskopf
Abstract: Subsequent to the detection of a gamma ray flare in September, Chandra
has been used to monitor the structure and spectrum of the Crab
Nebula. This flare was first detected by AGILE (ATEL 2855)and had a
timescale of days. The event was also seen with the Fermi Satellite.
These S/C have also observed flaring at other times and with longer
timescales. The Sept. event has received international attention and
it appears that the flaring is not directly associated with the
pulsar, but with the nebular flux. The timescale indicates an emitting
region as small as 0.5-1.0 arcsec at two kpc. Chandra has shown that
there are many features of this scale in the nebula and that they are
constantly changing. It is essential that a viable baseline be
established in order to obtain useful information from future
observations triggered by another flare. We propose a series of
monitoring observations.

Sequence Number: 501546

Title : Monitoring of the Crab Nebula
PI: Weisskopf
Abstract: Subsequent to the detection of a gamma ray flare in September, Chandra
has been used to monitor the structure and spectrum of the Crab
Nebula. This flare was first detected by AGILE (ATEL 2855)and had a
timescale of days. The event was also seen with the Fermi Satellite.
These S/C have also observed flaring at other times and with longer
timescales. The Sept. event has received international attention and
it appears that the flaring is not directly associated with the
pulsar, but with the nebular flux. The timescale indicates an emitting
region as small as 0.5-1.0 arcsec at two kpc. Chandra has shown that
there are many features of this scale in the nebula and that they are
constantly changing. It is essential that a viable baseline be
established in order to obtain useful information from future
observations triggered by another flare. We propose a series of
monitoring observations.

Sequence Number: 501545

Title : Monitoring of the Crab Nebula
PI: Weisskopf
Abstract: Subsequent to the detection of a gamma ray flare in September, Chandra
has been used to monitor the structure and spectrum of the Crab
Nebula. This flare was first detected by AGILE (ATEL 2855)and had a
timescale of days. The event was also seen with the Fermi Satellite.
These S/C have also observed flaring at other times and with longer
timescales. The Sept. event has received international attention and
it appears that the flaring is not directly associated with the
pulsar, but with the nebular flux. The timescale indicates an emitting
region as small as 0.5-1.0 arcsec at two kpc. Chandra has shown that
there are many features of this scale in the nebula and that they are
constantly changing. It is essential that a viable baseline be
established in order to obtain useful information from future
observations triggered by another flare. We propose a series of
monitoring observations.

Sequence Number: 501544

Title : Monitoring of the Crab Nebula
PI: Weisskopf
Abstract: Subsequent to the detection of a gamma ray flare in September, Chandra
has been used to monitor the structure and spectrum of the Crab
Nebula. This flare was first detected by AGILE (ATEL 2855)and had a
timescale of days. The event was also seen with the Fermi Satellite.
These S/C have also observed flaring at other times and with longer
timescales. The Sept. event has received international attention and
it appears that the flaring is not directly associated with the
pulsar, but with the nebular flux. The timescale indicates an emitting
region as small as 0.5-1.0 arcsec at two kpc. Chandra has shown that
there are many features of this scale in the nebula and that they are
constantly changing. It is essential that a viable baseline be
established in order to obtain useful information from future
observations triggered by another flare. We propose a series of
monitoring observations.

Sequence Number: 501543

Title : Monitoring of the Crab Nebula
PI: Weisskopf
Abstract: Subsequent to the detection of a gamma ray flare in September, Chandra
has been used to monitor the structure and spectrum of the Crab
Nebula. This flare was first detected by AGILE (ATEL 2855)and had a
timescale of days. The event was also seen with the Fermi Satellite.
These S/C have also observed flaring at other times and with longer
timescales. The Sept. event has received international attention and
it appears that the flaring is not directly associated with the
pulsar, but with the nebular flux. The timescale indicates an emitting
region as small as 0.5-1.0 arcsec at two kpc. Chandra has shown that
there are many features of this scale in the nebula and that they are
constantly changing. It is essential that a viable baseline be
established in order to obtain useful information from future
observations triggered by another flare. We propose a series of
monitoring observations.

Sequence Number: 501542

Title : Monitoring of the Crab Nebula
PI: Weisskopf
Abstract: Subsequent to the detection of a gamma ray flare in September, Chandra
has been used to monitor the structure and spectrum of the Crab
Nebula. This flare was first detected by AGILE (ATEL 2855)and had a
timescale of days. The event was also seen with the Fermi Satellite.
These S/C have also observed flaring at other times and with longer
timescales. The Sept. event has received international attention and
it appears that the flaring is not directly associated with the
pulsar, but with the nebular flux. The timescale indicates an emitting
region as small as 0.5-1.0 arcsec at two kpc. Chandra has shown that
there are many features of this scale in the nebula and that they are
constantly changing. It is essential that a viable baseline be
established in order to obtain useful information from future
observations triggered by another flare. We propose a series of
monitoring observations.

Sequence Number: 702511

Title : The bolometric luminosity of the z=7.08 QSO ULAS J1120+0641
PI: Simpson
Abstract: We have recently discovered the most distant QSO, ULAS J1120+0641, at
z=7.08, smashing the previous record of z=6.44. This object was
discovered by surveying 2250deg^2 of UKIDSS and SDSS, extending the
technique used by high-z QSO surveys into the near-IR. Based on its
rest-frame UV luminosity, the QSO is powered by a black hole of mass
~1e9Msun just 760Myr after the Big Bang. The presence of such a
massive collapsed object when the Universe was so young is a serious
challenge to models of structure formation and places strong
constraints on the growth of supermassive black holes in the early
Universe. We propose a CXO observation of ULAS J1120+0641 to measure
its X-ray flux. This will immediately provide a more reliable estimate
of its bolometric luminosity and black hole mass, and is also
necessary for us to determine the feasibility of a deep XMM spectral
observation to measure the X-ray photon index and Eddington ratio, and
compare its X-ray properties with those of other QSOs.

Sequence Number: 401291

Title : Confirming the low-mass X-ray binaries in the Kepler field
PI: Liu
Abstract: The Kepler mission has proved powerful in understanding the accretion
disks around compact objects for its un-interrupted monitoring
capability with time resolutions of minutes. Previous Kepler
observations of symbiotics and Cataclysmic Variables have successfully
probed the structures of the accretion flows around white dwarfs. In
the third and final Kepler cycle, we will seek to probe the accretion
flows around more compact neutron stars and black holes with Kepler
light curves, a regime never been studied before. There are no
existing studies of low-mass X-ray binaries (LMXBs) in the Kepler
field; we select LMXB candidates from ROSAT all sky survey (RASS)
sources in the Kepler field based on hardness ratios, X-ray-to-optical
ratios, and source extent aided by visual inspection. Here we propose
short Chandra observations for this sample of 15 LMXB candidates to
determine their exact nature and optical counterparts.

Sequence Number: 401290

Title : Confirming the low-mass X-ray binaries in the Kepler field
PI: Liu
Abstract: The Kepler mission has proved powerful in understanding the accretion
disks around compact objects for its un-interrupted monitoring
capability with time resolutions of minutes. Previous Kepler
observations of symbiotics and Cataclysmic Variables have successfully
probed the structures of the accretion flows around white dwarfs. In
the third and final Kepler cycle, we will seek to probe the accretion
flows around more compact neutron stars and black holes with Kepler
light curves, a regime never been studied before. There are no
existing studies of low-mass X-ray binaries (LMXBs) in the Kepler
field; we select LMXB candidates from ROSAT all sky survey (RASS)
sources in the Kepler field based on hardness ratios, X-ray-to-optical
ratios, and source extent aided by visual inspection. Here we propose
short Chandra observations for this sample of 15 LMXB candidates to
determine their exact nature and optical counterparts.

Sequence Number: 401289

Title : Confirming the low-mass X-ray binaries in the Kepler field
PI: Liu
Abstract: The Kepler mission has proved powerful in understanding the accretion
disks around compact objects for its un-interrupted monitoring
capability with time resolutions of minutes. Previous Kepler
observations of symbiotics and Cataclysmic Variables have successfully
probed the structures of the accretion flows around white dwarfs. In
the third and final Kepler cycle, we will seek to probe the accretion
flows around more compact neutron stars and black holes with Kepler
light curves, a regime never been studied before. There are no
existing studies of low-mass X-ray binaries (LMXBs) in the Kepler
field; we select LMXB candidates from ROSAT all sky survey (RASS)
sources in the Kepler field based on hardness ratios, X-ray-to-optical
ratios, and source extent aided by visual inspection. Here we propose
short Chandra observations for this sample of 15 LMXB candidates to
determine their exact nature and optical counterparts.

Sequence Number: 401288

Title : Confirming the low-mass X-ray binaries in the Kepler field
PI: Liu
Abstract: The Kepler mission has proved powerful in understanding the accretion
disks around compact objects for its un-interrupted monitoring
capability with time resolutions of minutes. Previous Kepler
observations of symbiotics and Cataclysmic Variables have successfully
probed the structures of the accretion flows around white dwarfs. In
the third and final Kepler cycle, we will seek to probe the accretion
flows around more compact neutron stars and black holes with Kepler
light curves, a regime never been studied before. There are no
existing studies of low-mass X-ray binaries (LMXBs) in the Kepler
field; we select LMXB candidates from ROSAT all sky survey (RASS)
sources in the Kepler field based on hardness ratios, X-ray-to-optical
ratios, and source extent aided by visual inspection. Here we propose
short Chandra observations for this sample of 15 LMXB candidates to
determine their exact nature and optical counterparts.

Sequence Number: 401287

Title : Confirming the low-mass X-ray binaries in the Kepler field
PI: Liu
Abstract: The Kepler mission has proved powerful in understanding the accretion
disks around compact objects for its un-interrupted monitoring
capability with time resolutions of minutes. Previous Kepler
observations of symbiotics and Cataclysmic Variables have successfully
probed the structures of the accretion flows around white dwarfs. In
the third and final Kepler cycle, we will seek to probe the accretion
flows around more compact neutron stars and black holes with Kepler
light curves, a regime never been studied before. There are no
existing studies of low-mass X-ray binaries (LMXBs) in the Kepler
field; we select LMXB candidates from ROSAT all sky survey (RASS)
sources in the Kepler field based on hardness ratios, X-ray-to-optical
ratios, and source extent aided by visual inspection. Here we propose
short Chandra observations for this sample of 15 LMXB candidates to
determine their exact nature and optical counterparts.

Sequence Number: 401286

Title : Confirming the low-mass X-ray binaries in the Kepler field
PI: Liu
Abstract: The Kepler mission has proved powerful in understanding the accretion
disks around compact objects for its un-interrupted monitoring
capability with time resolutions of minutes. Previous Kepler
observations of symbiotics and Cataclysmic Variables have successfully
probed the structures of the accretion flows around white dwarfs. In
the third and final Kepler cycle, we will seek to probe the accretion
flows around more compact neutron stars and black holes with Kepler
light curves, a regime never been studied before. There are no
existing studies of low-mass X-ray binaries (LMXBs) in the Kepler
field; we select LMXB candidates from ROSAT all sky survey (RASS)
sources in the Kepler field based on hardness ratios, X-ray-to-optical
ratios, and source extent aided by visual inspection. Here we propose
short Chandra observations for this sample of 15 LMXB candidates to
determine their exact nature and optical counterparts.

Sequence Number: 401285

Title : Confirming the low-mass X-ray binaries in the Kepler field
PI: Liu
Abstract: The Kepler mission has proved powerful in understanding the accretion
disks around compact objects for its un-interrupted monitoring
capability with time resolutions of minutes. Previous Kepler
observations of symbiotics and Cataclysmic Variables have successfully
probed the structures of the accretion flows around white dwarfs. In
the third and final Kepler cycle, we will seek to probe the accretion
flows around more compact neutron stars and black holes with Kepler
light curves, a regime never been studied before. There are no
existing studies of low-mass X-ray binaries (LMXBs) in the Kepler
field; we select LMXB candidates from ROSAT all sky survey (RASS)
sources in the Kepler field based on hardness ratios, X-ray-to-optical
ratios, and source extent aided by visual inspection. Here we propose
short Chandra observations for this sample of 15 LMXB candidates to
determine their exact nature and optical counterparts.

Sequence Number: 401284

Title : Confirming the low-mass X-ray binaries in the Kepler field
PI: Liu
Abstract: The Kepler mission has proved powerful in understanding the accretion
disks around compact objects for its un-interrupted monitoring
capability with time resolutions of minutes. Previous Kepler
observations of symbiotics and Cataclysmic Variables have successfully
probed the structures of the accretion flows around white dwarfs. In
the third and final Kepler cycle, we will seek to probe the accretion
flows around more compact neutron stars and black holes with Kepler
light curves, a regime never been studied before. There are no
existing studies of low-mass X-ray binaries (LMXBs) in the Kepler
field; we select LMXB candidates from ROSAT all sky survey (RASS)
sources in the Kepler field based on hardness ratios, X-ray-to-optical
ratios, and source extent aided by visual inspection. Here we propose
short Chandra observations for this sample of 15 LMXB candidates to
determine their exact nature and optical counterparts.

Sequence Number: 401283

Title : Confirming the low-mass X-ray binaries in the Kepler field
PI: Liu
Abstract: The Kepler mission has proved powerful in understanding the accretion
disks around compact objects for its un-interrupted monitoring
capability with time resolutions of minutes. Previous Kepler
observations of symbiotics and Cataclysmic Variables have successfully
probed the structures of the accretion flows around white dwarfs. In
the third and final Kepler cycle, we will seek to probe the accretion
flows around more compact neutron stars and black holes with Kepler
light curves, a regime never been studied before. There are no
existing studies of low-mass X-ray binaries (LMXBs) in the Kepler
field; we select LMXB candidates from ROSAT all sky survey (RASS)
sources in the Kepler field based on hardness ratios, X-ray-to-optical
ratios, and source extent aided by visual inspection. Here we propose
short Chandra observations for this sample of 15 LMXB candidates to
determine their exact nature and optical counterparts.

Sequence Number: 401282

Title : High resolution spectroscopy of the 11 Hz eclipsing pulsar in Terzan
5
PI: Bhattacharyya
Abstract: The observation of the unique neutron star low-mass X-ray binary
(LMXB) EXO 1745-248 during its current outburst holds the promise to
address several important scientific problems. These are (1) use of
narrow absorption and emission features to probe the ionized and
neutral components above the accretion disk of LMXBs (Jimenez-Garate
et al. 2003); (2) measurement of the disk inner edge radius from the
broad relativistic iron line, and hence to probe the strong gravity
regime and the neutron star parameters (Bhattacharyya and Strohmayer
2007; Cackett et al. 2008); and (3) measurement of the neutron star
radius-to-mass ratio from narrow surface atomic spectral lines during
thermonuclear X-ray bursts. An observation with Chandra is required
because (1) it has unique high-resolution spectral capability, and (2)
this satellite will be able to observe the source throughout the
outburst (which XMM-Newton and Suzaku cannot do because of Sun angle
constraints).

Sequence Number: 501540

Title : Study of spatial structure associated with a gamma-ray enhancement of
the Crab
PI: Weisskopf
Abstract: Both the AGILE and Fermi satellites detected significant variation in
the emission above 100 MeV from the Crab Nebula. Moreover, there
appears to be a 1100 day counter variation in the x-ray flux from the
nebula seen with a number of satellites (figure sent separately). The
source of the enhancement seems to be associated with the brightening
of a knot appearing in the vicinity of the pulsar as seen by our team
using both Chandra and subsequently HST. Only Chandra has the imaging
spectroscopic capability to study such features, which we would then
correlate with the gamma-ray flux.

Sequence Number: 501539

Title : Study of spatial structure associated with a gamma-ray enhancement of
the Crab
PI: Weisskopf
Abstract: Both the AGILE and Fermi satellites detected significant variation in
the emission above 100 MeV from the Crab Nebula. Moreover, there
appears to be a 1100 day counter variation in the x-ray flux from the
nebula seen with a number of satellites (figure sent separately). The
source of the enhancement seems to be associated with the brightening
of a knot appearing in the vicinity of the pulsar as seen by our team
using both Chandra and subsequently HST. Only Chandra has the imaging
spectroscopic capability to study such features, which we would then
correlate with the gamma-ray flux.

Sequence Number: 501538

Title : Study of spatial structure associated with a gamma-ray enhancement of
the Crab
PI: Weisskopf
Abstract: Both the AGILE and Fermi satellites detected significant variation in
the emission above 100 MeV from the Crab Nebula. Moreover, there
appears to be a 1100 day counter variation in the x-ray flux from the
nebula seen with a number of satellites (figure sent separately). The
source of the enhancement seems to be associated with the brightening
of a knot appearing in the vicinity of the pulsar as seen by our team
using both Chandra and subsequently HST. Only Chandra has the imaging
spectroscopic capability to study such features, which we would then
correlate with the gamma-ray flux.

Sequence Number: 501537

Title : Study of spatial structure associated with a gamma-ray enhancement of
the Crab
PI: Weisskopf
Abstract: Both the AGILE and Fermi satellites detected significant variation in
the emission above 100 MeV from the Crab Nebula. Moreover, there
appears to be a 1100 day counter variation in the x-ray flux from the
nebula seen with a number of satellites (figure sent separately). The
source of the enhancement seems to be associated with the brightening
of a knot appearing in the vicinity of the pulsar as seen by our team
using both Chandra and subsequently HST. Only Chandra has the imaging
spectroscopic capability to study such features, which we would then
correlate with the gamma-ray flux.

Sequence Number: 501536

Title : Study of spatial structure associated with a gamma-ray enhancement of
the Crab
PI: Weisskopf
Abstract: Both the AGILE and Fermi satellites detected significant variation in
the emission above 100 MeV from the Crab Nebula. Moreover, there
appears to be a 1100 day counter variation in the x-ray flux from the
nebula seen with a number of satellites (figure sent separately). The
source of the enhancement seems to be associated with the brightening
of a knot appearing in the vicinity of the pulsar as seen by our team
using both Chandra and subsequently HST. Only Chandra has the imaging
spectroscopic capability to study such features, which we would then
correlate with the gamma-ray flux.

Sequence Number: 501535

Title : Unveiling the nature of cyclic behavior in the period evolution of the
Anomalous X ray Pulsar XTE j1810-197
PI: Bernardini
Abstract: The goal of our analysis is to probe a possible long term (5 yr)
free-body precession of this neutron star for which we found several
indications based on a non-phase-connected timing analysis. Although
only 3 NS up to now have shown indication of precession, such evidence
strongly challenges our current understanding of the NS interior. The
standard picture of the outer core, in which superfluid neutrons
coexist with type II superconducting protons, requires revision. One
possibility is that protons are type I which would imply a significant
revision of our picture of the physical conditions in the NS core.
Another possibility is that the neutrons are normal in the outer core
which again affects our understanding of the physical state of NSs
core. The presence of long period modulation can shed light on the
physical properties of NS and thus help constraining its equation of
state

Sequence Number: 501534

Title : The first low-B soft gamma repeater: testing the magnetar model
PI: Rea
Abstract: On 2009 June 5 two SGR-like bursts were emitted by SGR 0418+5729
(Esposito et al. 2010, MNRAS, 405, 1787). Although this SGR showed all
the characteristics of SGRs' outbursts, a phase-coherent timing
solution over the first ∼500 d yielded no evidence for any pdot,
implying a 3σ u.l. on the B-field of <7.5 10^{12} G (Rea et al.
2010, Science in press). This is the lowest magnetic field ever
observed for a magnetar, and the first lower than the electron
critical B (~4x10^{13} G). Such a low a external dipolar B-field might
hide an internal high-B of ~10^{14} G, needed to trigger the
magnetar-like activity. The external B can be at most ~80 times the
dipolar surface B. We ask for an ACIS-S observation of 30ks in
December 2010 to keep the phase-coherence of our timing solution, and
hopefully have a final detection of the B-field of this low magnetic
field magnetar. If the B will end up to be < 10^12 Gauss, this would
pose serious difficulties on the magnetar model.

Sequence Number: 501533

Title : CHANDRA imaging of the cooling front after a high energy flare
PI: ferrigno
Abstract: The recently (Sept 19-21) observed flare of the Crab nebula above 100
MeV (ATEL 2855) is likely due to synchrotron emission of PeV electrons
injected either in the pulsar magnetosphere or close to the shock at
0.14 pc from the pulsar. If the injection happened close to the
pulsar, then high-energy particles are expected to reach the shock and
brighten it in one month time. If the flare is due to electron
injection at the shock, instabilities at the shock lead to an increase
of the injection rate which explains the observed gamma ray
brightening. At lower energies (ATELs 2856, 2858), the emission
remains stable because of longer cooling time. We expect an X-ray
counterpart of the gamma-ray flare in high resolution imaging
observation of the pulsar wind shock. With Chandra we can search for
structures/knots fading or moving (Hester et al. 2002). Follow-up
observations at later times (weeks to months) will be necessary to
follow the evolution of these structures.

Sequence Number: 501532

Title : CHANDRA imaging of the cooling front after a high energy flare
PI: ferrigno
Abstract: The recently (Sept 19-21) observed flare of the Crab nebula above 100
MeV (ATEL 2855) is likely due to synchrotron emission of PeV electrons
injected either in the pulsar magnetosphere or close to the shock at
0.14 pc from the pulsar. If the injection happened close to the
pulsar, then high-energy particles are expected to reach the shock and
brighten it in one month time. If the flare is due to electron
injection at the shock, instabilities at the shock lead to an increase
of the injection rate which explains the observed gamma ray
brightening. At lower energies (ATELs 2856, 2858), the emission
remains stable because of longer cooling time. We expect an X-ray
counterpart of the gamma-ray flare in high resolution imaging
observation of the pulsar wind shock. With Chandra we can search for
structures/knots fading or moving (Hester et al. 2002). Follow-up
observations at later times (weeks to months) will be necessary to
follow the evolution of these structures.

Sequence Number: 501531

Title : Search for new spatial structure associated with the gamma-ray
enhancement of the Crab
PI: Weisskopf
Abstract: It has just been reported (Atel 2555) that the AGILE satellite has
detected a significant variation in the emission above 100 MeV from
the environs of the Crab Nebula. A similar enhancement was seen at the
same time with the Fermi Satellite. If the source of this enhancement
is due to a new morphological feature (a new knot e.g. appearing in
the vicinity of the pulsar), then Chandra, because of its angular
resolution, is the only Observatory that can search for such a
feature.

Sequence Number: 401281

Title : Constraining the Spectrum of HLX-1 in Outburst
PI: Farrell
Abstract: HLX-1 currently provides the strongest evidence for the existence of
intermediate mass black holes. Previous observations with XMM and an
ongoing monitoring campaign with Swift have shown that it undergoes
similar spectral state transitions to stellar mass black hole
binaries, with large-scale flux variability by a factor of ~100 over
timescales of weeks to months. Our most recent Swift observation on
August 29th found that it has re-brightened and is currently at
Lx~1.3E42 erg/s, compared to Lx~3E40 erg/s only 3 weeks prior to this.
The spectrum also appears to be dominated by a soft thermal component.
We propose to observe this source with Chandra so as to constrain the
spectrum and luminosity and to search for variability that has been
detected in other states. We will thus be able to test for the
presence of a hard tail in the current spectrum, whether HLX-1 follows
the same Lx-Tin relationship as other ULXs, and whether the nH is
variable (related to outflows).

Sequence Number: 401145

Title : Measuring the spin of the black hole Cygnus X-1
PI: McClintock
Abstract: We are nearing completion of a paper on the spin of Cyg X-1. We
determine the spin by fitting the thermal accretion-disk component to
our fully relativistic disk model, while carefully modeling the
nonthermal component of emission. In this work, we have exhaustively
searched the HEASARC archives (over all time and all missions) for
useful spectra. Remarkably, there is only one suitable broadband
spectrum (a simultaneous observation by ASCA and RXTE made in 1999)
that allows us to constrain the power-law component. There is just
this single spectrum because Cyg X-1 is rarely in the required soft
state and because it has only rarely been observed with detectors
spanning the required energy interval (~1-30 keV). Cyg X-1 has just
entered the soft state. We propose to obtain 3 Chandra observations
(HETG; TE mode; 6 ks each) and will apply for simultaneous RXTE/PCA
coverage. We seek 3 observations because the quality of the soft
varies dramatically (see the references above).

Sequence Number: 401144

Title : Measuring the spin of the black hole Cygnus X-1
PI: McClintock
Abstract: We are nearing completion of a paper on the spin of Cyg X-1. We
determine the spin by fitting the thermal accretion-disk component to
our fully relativistic disk model, while carefully modeling the
nonthermal component of emission. In this work, we have exhaustively
searched the HEASARC archives (over all time and all missions) for
useful spectra. Remarkably, there is only one suitable broadband
spectrum (a simultaneous observation by ASCA and RXTE made in 1999)
that allows us to constrain the power-law component. There is just
this single spectrum because Cyg X-1 is rarely in the required soft
state and because it has only rarely been observed with detectors
spanning the required energy interval (~1-30 keV). Cyg X-1 has just
entered the soft state. We propose to obtain 3 Chandra observations
(HETG; TE mode; 6 ks each) and will apply for simultaneous RXTE/PCA
coverage. We seek 3 observations because the quality of the soft
varies dramatically (see the references above).

Sequence Number: 501371

Title : The first 'non-magnetar' soft gamma repeater
PI: Rea
Abstract: On 2009 June 5 two SGR-like bursts were emitted by a new SGR, SGR
0418+5729 (Esposito et al. 2010, MNRAS, 405, 1787), having a 9.1s spin
period. The outburst faded by a factor of ∼10 in about 200 days
when it became Sun constrained for many X-ray satellites. Although
this SGR showed all the characteristics of SGRs' outbursts, a
phase-coherent timing solution over the first ∼200 d yielded no
evidence for any pdot, implying a 3σ u.l. on the B-field of <1.5
10^{13} G. This is the lowest magnetic field ever observed for a
magnetar, and the first lower than the electron critical B (~4x10^{13}
G), posing serious problems to the magnetar model. The source became
visible again by Swift (and Chandra) a few days ago. Swift detected
the SGR (8sigma) but it showed a very low flux
(1.3x10^{-13}erg/s/cm2), too low to measure a periodicity with XRT. We
ask for an ACIS-S observation of 30ks within 15 days to have a final
detection of the B-field of this low magnetic field magnetar.

Sequence Number: 401141

Title : X-ray spectroscopy of Cir X-1 through its transition to an
exceptionally hard X-ray state
PI: D'A
Abstract: Following a long period of X-ray quiescence Cir X-1 shown a new X-ray
re-brightening from May 2010 (Atel #2608).The source has shown a
decline of its flux where the X-ray emission become dominated by
extended structures (Atel #2650, Atel #2674).A strong radio
re-brightening of the source was detected on June 24 by ATCA (Atel
#2699). The latest X-ray spectrum observed with Swift XRT (MJD
55373.47, June 26th) revealed an unusually hard spectrum (Gamma ~ 1
power-law) and absorbed by a local absorber (N_h 10^24 cm^-2).The
spectrum also shows an intense and broadened iron line at 6.4 keV
(eqw. width ~ 200 eV). We request a 20 ks Chandra/HETGS observation of
this source with these aims: to resolve the line emitting plasma and
the origin of the broadened iron line and to define the role and the
physical parameters of the plasma constituting the base of the jet
observed in the radio band.

Sequence Number: 900939

Title : The Chandra Deep Field-South Survey: An Ultradeep Chandra Legacy
PI: Tananbaum
Abstract: Director's Discretionary Observation to increase the exposure on the
Chandra Deep Field South from around 2 Msecs to around 4 Msecs.

Sequence Number: 900939

Title : The Chandra Deep Field-South Survey: An Ultradeep Chandra Legacy
PI: Tananbaum
Abstract: Director's Discretionary Observation to increase the exposure on the
Chandra Deep Field South from around 2 Msecs to around 4 Msecs.

Sequence Number: 900939

Title : The Chandra Deep Field-South Survey: An Ultradeep Chandra Legacy
PI: Tananbaum
Abstract: Director's Discretionary Observation to increase the exposure on the
Chandra Deep Field South from around 2 Msecs to around 4 Msecs.

Sequence Number: 900939

Title : The Chandra Deep Field-South Survey: An Ultradeep Chandra Legacy
PI: Tananbaum
Abstract: Director's Discretionary Observation to increase the exposure on the
Chandra Deep Field South from around 2 Msecs to around 4 Msecs.

Sequence Number: 900939

Title : The Chandra Deep Field-South Survey: An Ultradeep Chandra Legacy
PI: Tananbaum
Abstract: Director's Discretionary Observation to increase the exposure on the
Chandra Deep Field South from around 2 Msecs to around 4 Msecs.

Sequence Number: 501369

Title : Chandra Observations of the ultra-dark GRB 100615A
PI: Levan
Abstract: A fraction of gamma-ray bursts are dark in the optical and even in the
nIR. These can be localised only using X-ray afterglows. This sample
probably includes bursts in highly obscured, extreme star forming
regions, and may originate in decidedly different environments from
optically bright bursts. Unfortunately, Swift X-ray positions are not
sufficiently precise to allow unambiguous identification of the host
galaxies, while sub-arcsecond positions from Chandra do allow for this
identification. With position in hand we can search for the host
galaxy, study its luminosity and morphology, obtain its redshift and
measure the location of the burst upon it -- these observations can
then be compared to those of optically bright bursts to derive
meaningful constraints on the burst environment. All of this
subsequent science is enabled by a modest (15 ks) Chandra
observation.

Sequence Number: 900939

Title : The Chandra Deep Field-South Survey: An Ultradeep Chandra Legacy
PI: Tananbaum
Abstract: Director's Discretionary Observation to increase the exposure on the
Chandra Deep Field South from around 2 Msecs to around 4 Msecs.

Sequence Number: 900938

Title : The Chandra Deep Field-South Survey: An Ultradeep Chandra Legacy
PI: Tananbaum
Abstract: Director's Discretionary Observation to increase the exposure on the
Chandra Deep Field South from around 2 Msecs to around 4 Msecs.

Sequence Number: 900938

Title : The Chandra Deep Field-South Survey: An Ultradeep Chandra Legacy
PI: Tananbaum
Abstract: Director's Discretionary Observation to increase the exposure on the
Chandra Deep Field South from around 2 Msecs to around 4 Msecs.

Sequence Number: 501368

Title : Unveiling the nature of cyclic behavior in the period evolution of the
Anomalous X ray Pulsar XTE j1810-197
PI: Bernardini
Abstract: The goal of our analysis is to probe a possible long term (5 yr)
free-body precession of this neutron star for which we found several
indications based on a non-phase-connected timing analysis. Although
only 3 NS up to now have shown indication of precession, such evidence
strongly challenges our current understanding of the NS interior. The
standard picture of the outer core, in which superfluid neutrons
coexist with type II superconducting protons, requires revision. One
possibility is that protons are type I which would imply a significant
revision of our picture of the physical conditions in the NS core.
Another possibility is that the neutrons are normal in the outer core
which again affects our understanding of the physical state of NSs
core. The presence of long period modulation can shed light on the
physical properties of NS and thus help constraining its equation of
state

Sequence Number: 900938

Title : The Chandra Deep Field-South Survey: An Ultradeep Chandra Legacy
PI: Tananbaum
Abstract: Director's Discretionary Observation to increase the exposure on the
Chandra Deep Field South from around 2 Msecs to around 4 Msecs.

Sequence Number: 900938

Title : The Chandra Deep Field-South Survey: An Ultradeep Chandra Legacy
PI: Tananbaum
Abstract: Director's Discretionary Observation to increase the exposure on the
Chandra Deep Field South from around 2 Msecs to around 4 Msecs.

Sequence Number: 900938

Title : The Chandra Deep Field-South Survey: An Ultradeep Chandra Legacy
PI: Tananbaum
Abstract: Director's Discretionary Observation to increase the exposure on the
Chandra Deep Field South from around 2 Msecs to around 4 Msecs.

Sequence Number: 900936

Title : The Chandra Deep Field-South Survey: An Ultradeep Chandra Legacy
PI: Tananbaum
Abstract: Director's Discretionary Observation to increase the exposure on the
Chandra Deep Field South from around 2 Msecs to around 4 Msecs.

Sequence Number: 300283

Title : The maturing of the remarkable supersoft source KT Eri
PI: Drake
Abstract: LETGS observations of KT Eri in the early SSS phase revealed dramatic
changes in C and N absorption with time that probe their abundances in
the ejected envelope and the depth-dependent nucleosynthesis of the
central engine during the blast. Now the SSS has matured, the ejected
envelope will have dissipated, and a new observation will probe the
abundances in the radiatively-driven wind and evelope and the
steady-state CN-processing. Chandra is by far best suited for this
very soft, low NH target whose spectrum extends longward of 50A. A
continuous Chandra observation will have additional value for testing
a tentative Swift detection of a 35s periodicity possibly caused by
pulsations of the white dwarf.

Sequence Number: 900937

Title : The Chandra Deep Field-South Survey: An Ultradeep Chandra Legacy
PI: Tananbaum
Abstract: Director's Discretionary Observation to increase the exposure on the
Chandra Deep Field South from around 2 Msecs to around 4 Msecs.

Sequence Number: 900937

Title : The Chandra Deep Field-South Survey: An Ultradeep Chandra Legacy
PI: Tananbaum
Abstract: Director's Discretionary Observation to increase the exposure on the
Chandra Deep Field South from around 2 Msecs to around 4 Msecs.

Sequence Number: 900937

Title : The Chandra Deep Field-South Survey: An Ultradeep Chandra Legacy
PI: Tananbaum
Abstract: Director's Discretionary Observation to increase the exposure on the
Chandra Deep Field South from around 2 Msecs to around 4 Msecs.

Sequence Number: 900937

Title : The Chandra Deep Field-South Survey: An Ultradeep Chandra Legacy
PI: Tananbaum
Abstract: Director's Discretionary Observation to increase the exposure on the
Chandra Deep Field South from around 2 Msecs to around 4 Msecs.

Sequence Number: 900936

Title : The Chandra Deep Field-South Survey: An Ultradeep Chandra Legacy
PI: Tananbaum
Abstract: Director's Discretionary Observation to increase the exposure on the
Chandra Deep Field South from around 2 Msecs to around 4 Msecs.

Sequence Number: 401138

Title : X-ray Column Density Towards The Low Mass X-ray Binary 4U 1608-522
PI: Ozel
Abstract: We request a 25 ks observation of the transient low-mass X-ray binary
4U 1608-52 with Chandra HETG to measure the interstellar extinction
towards the source using absorption edges in its spectrum. 4U 1608-52
is one of our gold standard sources for the neutron star mass-radius
measurements. The column density is used to determine the distance to
the source employing a technique that makes use of red clump stars in
the field of view of the source. However, so far, only a 5ks XMM
observation has been available to measure the column density, which
results in large distance errors. Chandra observations will greatly
reduce this uncertainty by pinning down the column density with
grating observations, which, in turn, will significantly reduce the
uncertainties in the neutron star mass and radius.

Sequence Number: 900936

Title : The Chandra Deep Field-South Survey: An Ultradeep Chandra Legacy
PI: Tananbaum
Abstract: Director's Discretionary Observation to increase the exposure on the
Chandra Deep Field South from around 2 Msecs to around 4 Msecs.

Sequence Number: 300277

Title : U Sco in outburst
PI: Orio
Abstract: U Sco is a VERY peculiar recurrent nova, that does not have a giant
secondary and yet is very fast. The "speed" (of ejecta and light
curve) indicates an extremely massive white dwarf. The secondary has
lost a large part of its envelope and is extremely helium enriched,
indicating an evolved system altogether - one that may be close to a
type Ia supernova explosion! X-rays are the only window to the
extremely hot underlying white dwarf and in the case of U Sco, it
would be extremely interesting to find out whether it is a massive
white dwarf, and whether it is a CO or a Ne-O-Mg white dwarf. In a new
paper on the 2006 grating observations of RS Ophiuchi, E. Behar and I
have found overwhelming evidence that RS Oph hosts a Ne-O-Mg whire
dwarf, hence is not a type I a supernova candidate. This is based on
spectral lines that appeared only for a short amount of time and have
never been observed in astronomy before (we have laboratory
confirmation).

Sequence Number: 300276

Title : The bright super-supersoft souce phase of KT Eri
PI: Drake
Abstract: Further Chandra LETGS observations will take advantage of the rare
100+ Swift XRT count/s nova, KT Eri, to probe the nature of the
explosion through the properties of the expanding enveloped of the
SSS. KT Eri is a high galactic latitude (low NH) nova that exploded on
2009 November 14. The SSS phase was detected at 13 count/s in ongoing
Swift monitoring on 2010 January 19 (day 65.7), during which the soft
X-ray flux with BB kT~20eV varied dramatically by factors of ~20 on a
timescale of ~3 hours, similar to the SSS phases of RS Oph and V458
Vul. The Swift count rate had risen steadily to 150 count/s by January
25, accompanied by variability of a factor of 2-3. A 15ks Chandra
LETGS observation obtained on January 23-24 showed a highly detailed
spectrum with numerous prominent broadened absorption features and a
clear P Cygni profile in N VI. Chandra is by far best suited for this
very soft, low NH target whose spectrum extends longward of 50A.

Sequence Number: 300275

Title : The bright super-supersoft souce phase of KT Eri
PI: Drake
Abstract: Further Chandra LETGS observations will take advantage of the rare
100+ Swift XRT count/s nova, KT Eri, to probe the nature of the
explosion through the properties of the expanding enveloped of the
SSS. KT Eri is a high galactic latitude (low NH) nova that exploded on
2009 November 14. The SSS phase was detected at 13 count/s in ongoing
Swift monitoring on 2010 January 19 (day 65.7), during which the soft
X-ray flux with BB kT~20eV varied dramatically by factors of ~20 on a
timescale of ~3 hours, similar to the SSS phases of RS Oph and V458
Vul. The Swift count rate had risen steadily to 150 count/s by January
25, accompanied by variability of a factor of 2-3. A 15ks Chandra
LETGS observation obtained on January 23-24 showed a highly detailed
spectrum with numerous prominent broadened absorption features and a
clear P Cygni profile in N VI. Chandra is by far best suited for this
very soft, low NH target whose spectrum extends longward of 50A.

Sequence Number: 300274

Title : The early SSS phase of the Classical Nova KT Eri
PI: Ness
Abstract: All novae are thought to evolve through a SuperSoft (SSS) phase,
during which the hot (kT~20-50 eV) surface of the nuclear-burning
white dwarf is visible. However, novae evolve rapidly and only 3 novae
have been observed at high spectral resolution in X-rays during the
SSS phase. Our ongoing Swift monitoring of novae in outburst has
discovered that high-amplitude variations can occur in the SSS phase
(eg RS Oph, V458 Vul). The driver is unknown, and more observations
are needed. These oscillations were first seen during 2003 Chandra
observations of V4743 Sgr where a bright SSS (40 LETG cps)
transitioned into a 0.6 cps photoionized/-excited emission line
spectrum. The nova KT Eri has entered its SSS phase (today), and Swift
is seeing high amplitude flux oscillations. A Chandra LETGS
observation will probe the spectral properties of the SSS phase at
high spectral and temporal resolution. Since all novae have behaved
differently in X-rays, a larger sample is needed.

Sequence Number: 702317

Title : Gravitationally lensed quasar Q0957+561AB in outburst
PI: Goicoechea
Abstract: Q0957+561AB consists of two images, A and B, separated by 6 arcsec, of
a single quasar at z = 1.41. Optical monitoring of the lensed quasar
showed that the g-band flux of the leading image A increased 30% over
about 130 days. Taking the time delay into account, it is expected a
similar g-band brightening of the trailing image B in the first
semester of 2010 (see ATel#2228 on 5 Oct 2009). Thus, a
multiwavelength follow-up of this system over 2010 offers a unique
opportunity to study the involved mechanism of variability. There is
clear evidence that UV/optical variability of local AGN on restframe
timescales < 100 d is mainly driven by X-ray/EUV fluctuations that are
generated close to the accretion disc axis (reverberation scenario).
Chandra observations of Q0957+561B will allow us to check if the
expected optical event is triggered (and thus preceded) by an X-ray
flare. We want to confirm the reverberation scenario in a non-local (z
> 1) AGN for first time.

Sequence Number: 702316

Title : Gravitationally lensed quasar Q0957+561AB in outburst
PI: Goicoechea
Abstract: Q0957+561AB consists of two images, A and B, separated by 6 arcsec, of
a single quasar at z = 1.41. Optical monitoring of the lensed quasar
showed that the g-band flux of the leading image A increased 30% over
about 130 days. Taking the time delay into account, it is expected a
similar g-band brightening of the trailing image B in the first
semester of 2010 (see ATel#2228 on 5 Oct 2009). Thus, a
multiwavelength follow-up of this system over 2010 offers a unique
opportunity to study the involved mechanism of variability. There is
clear evidence that UV/optical variability of local AGN on restframe
timescales < 100 d is mainly driven by X-ray/EUV fluctuations that are
generated close to the accretion disc axis (reverberation scenario).
Chandra observations of Q0957+561B will allow us to check if the
expected optical event is triggered (and thus preceded) by an X-ray
flare. We want to confirm the reverberation scenario in a non-local (z
> 1) AGN for first time.

Sequence Number: 702315

Title : Gravitationally lensed quasar Q0957+561AB in outburst
PI: Goicoechea
Abstract: Q0957+561AB consists of two images, A and B, separated by 6 arcsec, of
a single quasar at z = 1.41. Optical monitoring of the lensed quasar
showed that the g-band flux of the leading image A increased 30% over
about 130 days. Taking the time delay into account, it is expected a
similar g-band brightening of the trailing image B in the first
semester of 2010 (see ATel#2228 on 5 Oct 2009). Thus, a
multiwavelength follow-up of this system over 2010 offers a unique
opportunity to study the involved mechanism of variability. There is
clear evidence that UV/optical variability of local AGN on restframe
timescales < 100 d is mainly driven by X-ray/EUV fluctuations that are
generated close to the accretion disc axis (reverberation scenario).
Chandra observations of Q0957+561B will allow us to check if the
expected optical event is triggered (and thus preceded) by an X-ray
flare. We want to confirm the reverberation scenario in a non-local (z
> 1) AGN for first time.

Sequence Number: 702314

Title : Gravitationally lensed quasar Q0957+561AB in outburst
PI: Goicoechea
Abstract: Q0957+561AB consists of two images, A and B, separated by 6 arcsec, of
a single quasar at z = 1.41. Optical monitoring of the lensed quasar
showed that the g-band flux of the leading image A increased 30% over
about 130 days. Taking the time delay into account, it is expected a
similar g-band brightening of the trailing image B in the first
semester of 2010 (see ATel#2228 on 5 Oct 2009). Thus, a
multiwavelength follow-up of this system over 2010 offers a unique
opportunity to study the involved mechanism of variability. There is
clear evidence that UV/optical variability of local AGN on restframe
timescales < 100 d is mainly driven by X-ray/EUV fluctuations that are
generated close to the accretion disc axis (reverberation scenario).
Chandra observations of Q0957+561B will allow us to check if the
expected optical event is triggered (and thus preceded) by an X-ray
flare. We want to confirm the reverberation scenario in a non-local (z
> 1) AGN for first time.

Sequence Number: 702313

Title : Gravitationally lensed quasar Q0957+561AB in outburst
PI: Goicoechea
Abstract: Q0957+561AB consists of two images, A and B, separated by 6 arcsec, of
a single quasar at z = 1.41. Optical monitoring of the lensed quasar
showed that the g-band flux of the leading image A increased 30% over
about 130 days. Taking the time delay into account, it is expected a
similar g-band brightening of the trailing image B in the first
semester of 2010 (see ATel#2228 on 5 Oct 2009). Thus, a
multiwavelength follow-up of this system over 2010 offers a unique
opportunity to study the involved mechanism of variability. There is
clear evidence that UV/optical variability of local AGN on restframe
timescales < 100 d is mainly driven by X-ray/EUV fluctuations that are
generated close to the accretion disc axis (reverberation scenario).
Chandra observations of Q0957+561B will allow us to check if the
expected optical event is triggered (and thus preceded) by an X-ray
flare. We want to confirm the reverberation scenario in a non-local (z
> 1) AGN for first time.

Sequence Number: 702312

Title : Gravitationally lensed quasar Q0957+561AB in outburst
PI: Goicoechea
Abstract: Q0957+561AB consists of two images, A and B, separated by 6 arcsec, of
a single quasar at z = 1.41. Optical monitoring of the lensed quasar
showed that the g-band flux of the leading image A increased 30% over
about 130 days. Taking the time delay into account, it is expected a
similar g-band brightening of the trailing image B in the first
semester of 2010 (see ATel#2228 on 5 Oct 2009). Thus, a
multiwavelength follow-up of this system over 2010 offers a unique
opportunity to study the involved mechanism of variability. There is
clear evidence that UV/optical variability of local AGN on restframe
timescales < 100 d is mainly driven by X-ray/EUV fluctuations that are
generated close to the accretion disc axis (reverberation scenario).
Chandra observations of Q0957+561B will allow us to check if the
expected optical event is triggered (and thus preceded) by an X-ray
flare. We want to confirm the reverberation scenario in a non-local (z
> 1) AGN for first time.

Sequence Number: 702311

Title : Gravitationally lensed quasar Q0957+561AB in outburst
PI: Goicoechea
Abstract: Q0957+561AB consists of two images, A and B, separated by 6 arcsec, of
a single quasar at z = 1.41. Optical monitoring of the lensed quasar
showed that the g-band flux of the leading image A increased 30% over
about 130 days. Taking the time delay into account, it is expected a
similar g-band brightening of the trailing image B in the first
semester of 2010 (see ATel#2228 on 5 Oct 2009). Thus, a
multiwavelength follow-up of this system over 2010 offers a unique
opportunity to study the involved mechanism of variability. There is
clear evidence that UV/optical variability of local AGN on restframe
timescales < 100 d is mainly driven by X-ray/EUV fluctuations that are
generated close to the accretion disc axis (reverberation scenario).
Chandra observations of Q0957+561B will allow us to check if the
expected optical event is triggered (and thus preceded) by an X-ray
flare. We want to confirm the reverberation scenario in a non-local (z
> 1) AGN for first time.

Sequence Number: 702310

Title : Gravitationally lensed quasar Q0957+561AB in outburst
PI: Goicoechea
Abstract: Q0957+561AB consists of two images, A and B, separated by 6 arcsec, of
a single quasar at z = 1.41. Optical monitoring of the lensed quasar
showed that the g-band flux of the leading image A increased 30% over
about 130 days. Taking the time delay into account, it is expected a
similar g-band brightening of the trailing image B in the first
semester of 2010 (see ATel#2228 on 5 Oct 2009). Thus, a
multiwavelength follow-up of this system over 2010 offers a unique
opportunity to study the involved mechanism of variability. There is
clear evidence that UV/optical variability of local AGN on restframe
timescales < 100 d is mainly driven by X-ray/EUV fluctuations that are
generated close to the accretion disc axis (reverberation scenario).
Chandra observations of Q0957+561B will allow us to check if the
expected optical event is triggered (and thus preceded) by an X-ray
flare. We want to confirm the reverberation scenario in a non-local (z
> 1) AGN for first time.

Sequence Number: 702309

Title : Gravitationally lensed quasar Q0957+561AB in outburst
PI: Goicoechea
Abstract: Q0957+561AB consists of two images, A and B, separated by 6 arcsec, of
a single quasar at z = 1.41. Optical monitoring of the lensed quasar
showed that the g-band flux of the leading image A increased 30% over
about 130 days. Taking the time delay into account, it is expected a
similar g-band brightening of the trailing image B in the first
semester of 2010 (see ATel#2228 on 5 Oct 2009). Thus, a
multiwavelength follow-up of this system over 2010 offers a unique
opportunity to study the involved mechanism of variability. There is
clear evidence that UV/optical variability of local AGN on restframe
timescales < 100 d is mainly driven by X-ray/EUV fluctuations that are
generated close to the accretion disc axis (reverberation scenario).
Chandra observations of Q0957+561B will allow us to check if the
expected optical event is triggered (and thus preceded) by an X-ray
flare. We want to confirm the reverberation scenario in a non-local (z
> 1) AGN for first time.

Sequence Number: 702308

Title : Gravitationally lensed quasar Q0957+561AB in outburst
PI: Goicoechea
Abstract: Q0957+561AB consists of two images, A and B, separated by 6 arcsec, of
a single quasar at z = 1.41. Optical monitoring of the lensed quasar
showed that the g-band flux of the leading image A increased 30% over
about 130 days. Taking the time delay into account, it is expected a
similar g-band brightening of the trailing image B in the first
semester of 2010 (see ATel#2228 on 5 Oct 2009). Thus, a
multiwavelength follow-up of this system over 2010 offers a unique
opportunity to study the involved mechanism of variability. There is
clear evidence that UV/optical variability of local AGN on restframe
timescales < 100 d is mainly driven by X-ray/EUV fluctuations that are
generated close to the accretion disc axis (reverberation scenario).
Chandra observations of Q0957+561B will allow us to check if the
expected optical event is triggered (and thus preceded) by an X-ray
flare. We want to confirm the reverberation scenario in a non-local (z
> 1) AGN for first time.

Sequence Number: 702307

Title : Gravitationally lensed quasar Q0957+561AB in outburst
PI: Goicoechea
Abstract: Q0957+561AB consists of two images, A and B, separated by 6 arcsec, of
a single quasar at z = 1.41. Optical monitoring of the lensed quasar
showed that the g-band flux of the leading image A increased 30% over
about 130 days. Taking the time delay into account, it is expected a
similar g-band brightening of the trailing image B in the first
semester of 2010 (see ATel#2228 on 5 Oct 2009). Thus, a
multiwavelength follow-up of this system over 2010 offers a unique
opportunity to study the involved mechanism of variability. There is
clear evidence that UV/optical variability of local AGN on restframe
timescales < 100 d is mainly driven by X-ray/EUV fluctuations that are
generated close to the accretion disc axis (reverberation scenario).
Chandra observations of Q0957+561B will allow us to check if the
expected optical event is triggered (and thus preceded) by an X-ray
flare. We want to confirm the reverberation scenario in a non-local (z
> 1) AGN for first time.

Sequence Number: 702306

Title : Gravitationally lensed quasar Q0957+561AB in outburst
PI: Goicoechea
Abstract: Q0957+561AB consists of two images, A and B, separated by 6 arcsec, of
a single quasar at z = 1.41. Optical monitoring of the lensed quasar
showed that the g-band flux of the leading image A increased 30% over
about 130 days. Taking the time delay into account, it is expected a
similar g-band brightening of the trailing image B in the first
semester of 2010 (see ATel#2228 on 5 Oct 2009). Thus, a
multiwavelength follow-up of this system over 2010 offers a unique
opportunity to study the involved mechanism of variability. There is
clear evidence that UV/optical variability of local AGN on restframe
timescales < 100 d is mainly driven by X-ray/EUV fluctuations that are
generated close to the accretion disc axis (reverberation scenario).
Chandra observations of Q0957+561B will allow us to check if the
expected optical event is triggered (and thus preceded) by an X-ray
flare. We want to confirm the reverberation scenario in a non-local (z
> 1) AGN for first time.

Sequence Number: 401137

Title : Chandra High Resolution Spectroscopy of the Be X-Ray binary A0535+262
PI: Reynolds
Abstract: We propose to observe the Be X-ray pulsar binary 1A 0535+262 with
Chandra HETGS for 20 ks. This observations will allow us to
investigate: 1) High M_dot accretion onto a NS: These observations
will allow us to probe accretion at a high fraction of the Eddington
luminosity onto a neutron star with an accurately constrained B-field
(4e12 -- Cyclotron lines) and spin period (X-ray pulsations). 2) Disk
winds from accreting compact objects: Miller et al. (2008) have
previously obtained HETGS spectra of the black hole transient GRO
J1655-40; while Ueda et al. (2004) have obtained HETGS spectra of the
Z-source GX13+1. In both cases numerous wind absorption lines are
observed. 3) Relativistic accretion disk emission lines: Cackett et
al. (2009) have observed relativistic Fe emission from a sample of
accreting neutron star LMXBs (Z, Atoll, MSP) providing constraints on
the radius of the neutron star. This will be the definitive Chandra
observation of a Be X-ray binary.

Sequence Number: 401137

Title : Chandra High Resolution Spectroscopy of the Be X-Ray binary A0535+262
PI: Reynolds
Abstract: We propose to observe the Be X-ray pulsar binary 1A 0535+262 with
Chandra HETGS for 20 ks. This observations will allow us to
investigate: 1) High M_dot accretion onto a NS: These observations
will allow us to probe accretion at a high fraction of the Eddington
luminosity onto a neutron star with an accurately constrained B-field
(4e12 -- Cyclotron lines) and spin period (X-ray pulsations). 2) Disk
winds from accreting compact objects: Miller et al. (2008) have
previously obtained HETGS spectra of the black hole transient GRO
J1655-40; while Ueda et al. (2004) have obtained HETGS spectra of the
Z-source GX13+1. In both cases numerous wind absorption lines are
observed. 3) Relativistic accretion disk emission lines: Cackett et
al. (2009) have observed relativistic Fe emission from a sample of
accreting neutron star LMXBs (Z, Atoll, MSP) providing constraints on
the radius of the neutron star. This will be the definitive Chandra
observation of a Be X-ray binary.

Sequence Number: 900936

Title : The Chandra Deep Field-South Survey: An Ultradeep Chandra Legacy
PI: Tananbaum
Abstract: Director's Discretionary Observation to increase the exposure on the
Chandra Deep Field South from around 2 Msecs to around 4 Msecs.

Sequence Number: 900939

Title : The Chandra Deep Field-South Survey: An Ultradeep Chandra Legacy
PI: Tananbaum
Abstract: Director's Discretionary Observation to increase the exposure on the
Chandra Deep Field South from around 2 Msecs to around 4 Msecs.

Sequence Number: 900939

Title : The Chandra Deep Field-South Survey: An Ultradeep Chandra Legacy
PI: Tananbaum
Abstract: Director's Discretionary Observation to increase the exposure on the
Chandra Deep Field South from around 2 Msecs to around 4 Msecs.

Sequence Number: 900939

Title : The Chandra Deep Field-South Survey: An Ultradeep Chandra Legacy
PI: Tananbaum
Abstract: Director's Discretionary Observation to increase the exposure on the
Chandra Deep Field South from around 2 Msecs to around 4 Msecs.

Sequence Number: 900938

Title : The Chandra Deep Field-South Survey: An Ultradeep Chandra Legacy
PI: Tananbaum
Abstract: Director's Discretionary Observation to increase the exposure on the
Chandra Deep Field South from around 2 Msecs to around 4 Msecs.

Sequence Number: 900938

Title : The Chandra Deep Field-South Survey: An Ultradeep Chandra Legacy
PI: Tananbaum
Abstract: Director's Discretionary Observation to increase the exposure on the
Chandra Deep Field South from around 2 Msecs to around 4 Msecs.

Sequence Number: 900938

Title : The Chandra Deep Field-South Survey: An Ultradeep Chandra Legacy
PI: Tananbaum
Abstract: Director's Discretionary Observation to increase the exposure on the
Chandra Deep Field South from around 2 Msecs to around 4 Msecs.

Sequence Number: 900937

Title : The Chandra Deep Field-South Survey: An Ultradeep Chandra Legacy
PI: Tananbaum
Abstract: Director's Discretionary Observation to increase the exposure on the
Chandra Deep Field South from around 2 Msecs to around 4 Msecs.

Sequence Number: 900937

Title : The Chandra Deep Field-South Survey: An Ultradeep Chandra Legacy
PI: Tananbaum
Abstract: Director's Discretionary Observation to increase the exposure on the
Chandra Deep Field South from around 2 Msecs to around 4 Msecs.

Sequence Number: 900937

Title : The Chandra Deep Field-South Survey: An Ultradeep Chandra Legacy
PI: Tananbaum
Abstract: Director's Discretionary Observation to increase the exposure on the
Chandra Deep Field South from around 2 Msecs to around 4 Msecs.

Sequence Number: 900937

Title : The Chandra Deep Field-South Survey: An Ultradeep Chandra Legacy
PI: Tananbaum
Abstract: Director's Discretionary Observation to increase the exposure on the
Chandra Deep Field South from around 2 Msecs to around 4 Msecs.

Sequence Number: 900936

Title : The Chandra Deep Field-South Survey: An Ultradeep Chandra Legacy
PI: Tananbaum
Abstract: Director's Discretionary Observation to increase the exposure on the
Chandra Deep Field South from around 2 Msecs to around 4 Msecs.

Sequence Number: 900936

Title : The Chandra Deep Field-South Survey: An Ultradeep Chandra Legacy
PI: Tananbaum
Abstract: Director's Discretionary Observation to increase the exposure on the
Chandra Deep Field South from around 2 Msecs to around 4 Msecs.

Sequence Number: 200656

Title : X-ray Emission from V838 Mon: Stellar Merger or Ejecta-Companion
Interactions?
PI: Kastner
Abstract: The nature of the infamous 2002 outburst of V838 Mon (Bond 2007;
Tylenda et al. 2009 [T09]) remains uncertain. No nova-like "hot phase"
was observed and the presence of a B3V companion and a small cluster
implies the system is too young to harbor an accreting white dwarf.
Among the leading models for the outburst is that of a stellar merger
(Soker & Tylenda 2007 [ST07]). The merger product should become
magnetically active well after outburst (ST07), suggesting that V838
Mon should make a delayed appearance as an X-ray source. Indeed, V838
Mon went undetected by CXO in 2003 (Orio et al 2003), but when we
reobserved the object in 2008 with XMM we detected a luminous X-ray
source very near its position (Antonini et al 2009). This source may
be the spun-up merger remnant. However, V838Mon s ejecta had just
engulfed its companion at the time of our XMM observation (T09). Hence
the XMM source might be due instead to interactions between V838 Mon s
ejecta and its companion.

Sequence Number: 401125

Title : A precise position for the intermediate mass black hole candidate in
ESO 243-49
PI: Farrell
Abstract: We recently identified a ULX that provides the strongest evidence for
the existence of intermediate mass black holes (Farrell et al., 2009,
Nature, 460, 73). Previous observations with XMM and Swift gave
incompatible positions at the 1 sigma level. We obtained a 1 ks
Chandra DDT observation on 07/04/09 to resolve this discrepancy. The
ULX was not detected, so has dropped by a factor >6 in flux. By
analogy with stellar mass black holes, this might indicate a
transition into a low/hard state; such a transition has never been
observed so far from any ULX. Triggered by this result and the unique
properties of the source, we are currently preparing requests for deep
ground and space-based telescope observations, whose analysis will
require a high precision that only Chandra can provide. Even a
non-detection would be a highly significant result, as it could
indicate the ULX has undergone a transition into the low/hard state; a
phenomenon commonly observed in Galactic X-ray binaries.

Sequence Number: 401124

Title : Following the Decay of NGC 6440 X-2
PI: Heinke
Abstract: On July 28-29, our GO Chandra image of NGC 6440 discovered a 2nd
transient LMXB in outburst in the globular cluster NGC 6440 (Atel
2139). RXTE/PCA saw indications of flaring at 0.7 Hz, similar to 1 Hz
flaring from SAX J1808, which indicated propeller instabilities in the
flow (Patruno+09). We request one 5-ksec ACIS-S observation of NGC
6440 by August 14 to determine whether this transient has returned to
full quiescence (<1e31) or undergoes accretion instabilities at low
(Lx~5e32) levels, as SAX J1808 did (Campana+08). 5 ksec will give >10
cts for Lx(0.5-10)>3e32 ergs/s (either BB @0.2 keV, or PL @index~2.2
as seen by Swift for 6440 X-2).

Sequence Number: 501174

Title : Searching for the X-ray counterpart to J1622-49
PI: Rea
Abstract: A new neutron star has been recently discovered during the Parkes High
Time Resolution Universe Survey. Its radio emission is highly variable
reaching strong luminosities (up to ~35mJy). We ask for a 20ks Chandra
ACIS-I observation to characterize its X-ray counterpart, in search
for a similarly variable X-ray emission.

Sequence Number: 701973

Title : The nature of the highly-variable X-ray galaxy KUG 1259+280
PI: Watson
Abstract: We have discovered a bright, strongly variable 2XMM X-ray source which
is <2" from the nucleus of a nearby (D~100 Mpc) post-starburst galaxy
KUG 1259+280. In the XMM-Newton discovery observation the source shows
a strong flare lasting 2500 sec with a factor ~8 flux increase on a
timescale <1000 sec. Even more remarkably the X-ray spectrum is
characterized by an unprecedently soft continuum well-fit with a
power-law model with gamma=4.7. The short-timescale variability,
luminosity (Lx~3E41 erg/sec) and location close to the nucleus
suggests an NLS1 AGN, but only weak, narrow Balmer lines (consistent
with starburst) are detected in the SDSS spectrum once host galaxy
contamination is removed. Proposed Chandra observation will locate the
X-ray source to ~0.2 arcsec (~100 pc) to see if it is truly coincident
with the nucleus - importantly if it is off-nucleus this would make it
an ULX. Observation will also check for faint extended X-ray emission
and constrain variability/spectrum.

Sequence Number: 401066

Title : A precise position for the intermediate mass black hole candidate in
ESO 243-49
PI: Farrell
Abstract: While investigating the 2XMM catalogue, we identified a new ULX in the
galaxy ESO 243-49 with an unabsorbed 0.2-10 keV Lx = 1.1E42 erg/s. A
follow-up DDT observation with XMM found the spectrum had changed
significantly, ruling out multiple low-luminosity sources. The Lx is
almost an order of magnitude greater than the previous record holder,
which when taken with the steep power-law spectrum and lack of radio
emission rules out beaming. This ULX, with a conservative mass lower
limit of ~500 Msun, provides the strongest evidence for the existence
of intermediate mass black holes (Farrell et al., 2009, Nature, in
press). This object is unique, puzzling and worth following-up given
the significance of the results. We will begin monitoring this ULX
with Swift in August to search for variability. Any significant
changes in flux/spectrum will trigger requests for deep observations
with ground based telescopes. Before such observations can take place
a high precision position is required.

Sequence Number: 401065

Title : Simultaneous Chandra/ATCA observation of GRO J1655-40 in quiescence
PI: Gallo
Abstract: We have recently been awarded a very deep (12 hr) radio observation of
the quiescent X-ray binary GRO J1655-40 with the newly refurbished
Australia Telescope Compact Array (ATCA) on June 7. The goal of this
observation is to probe jet formation at the lowest possible mass
accretion rates. Beside A0620-00, which was observed simultaneously by
the VLA and Chandra in 2005 (Gallo et al. 2006, MNRAS, 370, 1351),
there is only one other quiescent black-hole system whose properties
enable us to probe jet formation at such low accretion rates, and that
is GRO J1655-40. As well as anchoring the radio:X-ray correlation at
the lowest luminosities, we should be also able to detect the radio
spectrum of a truly quiescent source for the first time. In turn, this
will allow us to compare the broadband spectral energy distribution of
a quiescent stellar mass black hole to that of the quiescent 4E+6
solar mass black hole in the Galactic Center.

Sequence Number: 200569

Title : X-ray emission from the pre-main sequence star ZCMa during a
FUOri-type outburst
PI: Stelzer
Abstract: We propose for the first X-ray spectrum of an FUOri object during
outburst. The FUOR phenomenon is associated with a sudden increase of
the accretion rate in some pre-main sequence (PMS) stars, possibly due
to changes in the magnetic field. In the first X-ray survey of FUORs
Skinner et al. (2007) have detected two of four targets. None of them
was in outburst at the time. The typical two-temperature spectrum of a
PMS star requires in the case of FUOri different absorptions for the
soft and hard components (Skinner et al. 2006). Our target ZCMa is a
young F-type FUOR. In Feb 2008 ZCMa started its so far largest
outburst, with a further enhancement ~2 weeks ago. In May 2008 we have
detected its magnetic field. Now we aim at an X-ray detection of ZCMa
in its super-outburst'.

Sequence Number: 200568

Title : The current X-ray status of the planet bearing host star 51 Peg
PI: Schmitt
Abstract: In a 50 ksec XMM pointing we found a X-ray flux drop of >20 (compared
to ROSAT) for 51 Peg, the most famous planet-bearing host star. 51 Peg
is of very low activity and its chromospheric flux has been stable
over many years. A dramatic (downward) change in soft X-ray flux has
never been observed before in any star with the possible exception of
Alpha Cen. It is important to check how long this extremely low
activity state of 51 Peg persists. The X-ray surface flux derived from
the XMM lies more than one order of magnitude below expectation. A
possible solution is a coronal temperature change. An HRC pointing
with its larger low energy sensitivity will show if there is
undetected flux in the 0.1-0.2 keV band or if 51 Peg's corona has
almost completely disappeared from the X-ray world.

Sequence Number: 200568

Title : The current X-ray status of the planet bearing host star 51 Peg
PI: Schmitt
Abstract: In a 50 ksec XMM pointing we found a X-ray flux drop of >20 (compared
to ROSAT) for 51 Peg, the most famous planet-bearing host star. 51 Peg
is of very low activity and its chromospheric flux has been stable
over many years. A dramatic (downward) change in soft X-ray flux has
never been observed before in any star with the possible exception of
Alpha Cen. It is important to check how long this extremely low
activity state of 51 Peg persists. The X-ray surface flux derived from
the XMM lies more than one order of magnitude below expectation. A
possible solution is a coronal temperature change. An HRC pointing
with its larger low energy sensitivity will show if there is
undetected flux in the 0.1-0.2 keV band or if 51 Peg's corona has
almost completely disappeared from the X-ray world.

Sequence Number: 401051

Title : Is XTE J1701-407 Extended?
PI: Kaplan
Abstract: We recently observed the neutron star X-ray transient XTE J1701-407
with Chandra, using 1 ks of ACIS-S data for localization. However, the
Chandra data do not show a point source. Instead the source appears
extended over ~6 arcsec. We have investigated the data, consulting
with experts both at MIT and SAO, and cannot ascribe the data to
purely instrumental effects (aspect errors or pileup). The extended
X-ray emission could come from an outflow or a dust scattering halo -
both very interesting and rare phenomena. Jets allow detailed
calorimetry of the outbursts, while scattering halos lead to geometric
distances. We request a 5 ks ACIS-S subarray observation to
definitively assess the morphology, trying to discriminate between
these scenarios before the target fades into quiescence.

Sequence Number: 501152

Title : The X-ray light-curve of GRB 080307
PI: Page
Abstract: The canonical X-ray light-curve with a steep-plateau-normal decay, has
been attributed to continued energy injection; when this input ceases,
we see the steepening to the standard decay (alpha~1.3). In the case
of GRB 080307, the onset of the plateau was unusually late and,
uniquely, the decay was still continuing with a slope of <1 more than
a month after the burst. If intrinsic, this slow decay would place
severe constraints on the proposed injection model, requiring the
engine to be active for a very long time. Deep Gemini imaging reveals
a second optical source within the XRT error circle, which is a
possible source of contamination. Chandra's PSF and sensitivity will
allow us to test whether there is any contamination from this nearby
source and whether the decay has broken.

Sequence Number: 401050

Title : V Puppis: A black hole triple?
PI: Maccarone
Abstract: The nearby eclipsing binary VPup has recently been suggested on the
basis of eclipse timing residuals to have a third body with a ~5 year
orbital period and a mass of ~10 solar masses, but for which there is
no spectroscopic evidence, making it the only strong candidate for
having a black hole in a wide binary in the Galaxy. At a distance of
300 pc, this object can be studied in great detail, even if it is
extremely faint, and is the only black hole candidate with a Hipparcos
parallax distance. Past observatories showed variable X-ray emission
from this region at a level which was reasonable for Bondi accretion
from the stellar wind of the B giant in the VPup. We have recently
made ATCA observations of this region and need X-ray observations as
well, to compare the two fluxes or upper limits to determine whether
it is reasonable for such a flux ratio to come from a stellar mass
black hole, and to ensure that the past X-ray emission really is from
VPup, rather than a nearby object.

Sequence Number: 400934

Title : Locating the Ultraluminous Supersoft X-ray Source in NGC300
PI: Kong
Abstract: We propose to obtain the first Chandra image of the nearest very
luminous (Lx=1e38-1e39 erg/s) recurrent supersoft X-ray source (SSS)
currently in outburst. The source, located in NGC300, has a 5.4-hr
period and is ultraluminous in the high state. In AO-7, we obtained a
Chandra HRC-I observation to locate the position in order to search
for the optical counterpart in archival HST and VLT images. However,
the source was off with a 99% upper limit of 3.5e37 erg/s (ATel#1560).
NGC300 was observed with Swift on 2008 5/20, 6/4, and 6/19. The SSS
was clearly detected with XRT in all observations and all the source
photons are from below 0.7 keV, consistent with a SSS. The 0.2-2 keV
unabsorbed luminosity is about 1.5-2e38 erg/s (ATel#1560). If the
companion can be identified, we can set a strong constraint on the
donor and conclude whether the compact object is an IMBH. It would
also provide important information about the formation of SSS in a
black hole binary system.

Sequence Number: 400933

Title : The cold neutron star in the long-duration transient AX J1754.2-2754
PI: Keek
Abstract: As written in Atel#1575, J1754j went to quiescence after a long
outburst. The source is an ultra-compact X-ray binary. The long
outburst duration and ultra-compact nature make this source resemble
H1905+000. The current Chandra non-detection, based on a 2 ks-long
observation, shows that J1754 is very faint already given that the
long outburst duration facilitates a high neutron star crust
temperature. The low flux and the relatively high N_H forego
triggering the Wijnands et al. ToO (which is based on measuring
neutron star X-ray spectra). Instead, we propose to obtain one 30 ks
observation to search for J1754 in quiescence. In 30 ks we would reach
a flux limit of ~5E-15 erg cm-2 s-1, yielding a luminosity limit of
5E31 erg/s. A non-detection would make J1754 the second UCXB to be
very cold (after H1905) suggesting that the UC nature and hence the
composition of the accreted material is important for setting the NS
temperature and or the cooling rate.

Sequence Number: 501018

Title : An Unexpected Re-Brightening in SHB 080503: Afterglow or
mini-Supernova, 2nd Epoch
PI: Butler
Abstract: Gaining a deep understanding of the origin and nature of Short
(duration) Hard (spectrum) Gamma-ray Bursts (SHBs) is one of the last
frontiers of GRB research. We can now say almost for certain that the
progenitors of SHBs are different from those of Long-Soft GRBs (LSBs).
This is based almost entirely on observations of the host galaxies of
SHBs, which seem to be an older population than the hosts of LSBs:
whereas the 50+ hosts of LSBs appear to be underluminous star bursts,
and a handful of the bursts themselves have been directly associated
with supernova (SN) explosions. SHB hosts span the range from giant
elliptical to faint blue galaxies. A multi-wavelength campaign is
critical to ameliorate the large theoretical uncertainty as to what
types of progenitor systems --- a possible mini-SN'' (Li \&
Paczynski 1998) from a compact object mergers or binary WD merger
(Levan et al. 2006) --- are at the origin of SHBs.

Sequence Number: 501017

Title : An Unexpected Re-Brightening in SHB 080503: Afterglow or
mini-Supernova
PI: Butler
Abstract: Gaining a deep understanding of the origin and nature of Short
(duration) Hard (spectrum) Gamma-ray Bursts (SHBs) is one of the last
frontiers of GRB research. We can now say almost for certain that the
progenitors of SHBs are different from those of Long-Soft GRBs (LSBs).
This is based almost entirely on observations of the host galaxies of
SHBs, which seem to be an older population than the hosts of LSBs:
whereas the 50+ hosts of LSBs appear to be underluminous star bursts,
and a handful of the bursts themselves have been directly associated
with supernova (SN) explosions. SHB hosts span the range from giant
elliptical to faint blue galaxies. A multi-wavelength campaign is
critical to ameliorate the large theoretical uncertainty as to what
types of progenitor systems --- a possible mini-SN'' (Li \&
Paczynski 1998) from a compact object mergers or binary WD merger
(Levan et al. 2006) --- are at the origin of SHBs.

Sequence Number: 400932

Title : Chandra follow up of XTE J1719-291
PI: Sala
Abstract: XTE J1719-291 is a new, faint X-ray transient, discovered with
RXTE/PCA on March 21 (ATel#1442). PCA monitoring indicated an initial
rise followed by a delcine. Swift/XRT follow up on 30 March and April
3 provided the position with an uncertainty of 3.8 arcsec and
confirmed the decline (ATel#1451,#1467). The XRT spectrum was fit with
an absorbed powerlaw with nH=6e21cm-2 and a photon index of 3. A more
recent Swift observation on April 9 showed a re-brightening by a
factor 10 and a hardening of the spectrum (ATel#1467), with a photon
index of 2.5 and a 2-10 keV absorbed flux of 1.4e-11 erg/cm2/s. There
are no known objects in Simbad or ROSAT catalogues within the XRT
error circle. To identify the IR counterpart, we observed XTE J1719 on
April 11 in 7 bands (grizJHK) with GROND at the MPI/ESO 2.2m telescope
at La Silla. We find 13 near-infrared sources in the XRT error circle.
The transient properties are unusual, so it's unclear what kind of NIR
variability is to be expected.

Sequence Number: 701771

Title : Chandra observation of a flaring galaxy with strong optical
emission-line light echo
PI: Komossa
Abstract: We have discovered among SDSS-DR6, in Dec. 2007, a galaxy which is
unique in showing super-strong high-ionization iron lines and very
unusual double-peaked Balmer lines which are fading away, but have not
yet disappeared. The high degree of line ionization implies that we
see the light-echo of an (unobserved) EUV-X-ray flare. We have
confirmed, with optical ToO photometry on Jan. 1, 2008 the low-energy
tail of this flare in the optical and NIR. Only a few X-ray flaring
galaxies are known. This is the first time we have seen such a broad
line and continuum response. With Chandra, we will for the first time
detect the actual X-rays from this flare, characterize the X-ray
emission, locate the flare within 1 kpc of the nucleus, and test the
favored scenario - tidal disruption of a star - before the flare has
faded away. Depending on the measured source's X-ray brightness, we
will then consider X-ray monitoring to map the emission-line changes
in response to the X-ray fading.

Sequence Number: 400931

Title : A rare transient in M81: a merger event?
PI: Jonker
Abstract: A recently discovered optical transient (OT) in M81 (atel #1330) can
not be explained by a known transient event, it is a very good merger
candidate (NS-NS, BH-NS). Distinguishing properties are: decay rate is
too fast for a NOVA, optical brightness is too low for a SN (MV=-7.3),
the K-band magnitude and NIR colors rule out a foreground flaring
M-dwarf, the source is too bright for an transient X-ray binary. We
searched the Chandra archive for the presence of an X-ray source. None
was found even after stacking all the ACIS data. A transient X-ray
source was observed on 2000-05-07 in Chandra OBS ID 735 close to the
position of the OT. However, the distance to the position of the OT
was 2.8 arcsec which is too much for the two events to come from the
same source. The optical decay time matches the predicted decay time
for a merger event (Sylvestre 2003). If this OT is a merger event,
X-rays are predicted to be emitted due to either fall back or
radio-active decay of ejected material.

Sequence Number: 501014

Title : Chandra observations of a nearby supernova
PI: Roelofs
Abstract: We propose Chandra observations of the nearby type-Ia supernova
SN2007on to characterize its X-ray emission, which will help us
constrain the nature of the progenitor. We ask for an initial 40ks
which will enable us to put useful constraints on its X-ray flux.

Sequence Number: 501014

Title : Chandra observations of a nearby supernova
PI: Roelofs
Abstract: We propose Chandra observations of the nearby type-Ia supernova
SN2007on to characterize its X-ray emission, which will help us
constrain the nature of the progenitor. We ask for an initial 40ks
which will enable us to put useful constraints on its X-ray flux.

Sequence Number: 200526

Title : The physics of flares in young stellar objects
PI: Micela
Abstract: Flares are the most extreme manifestation of stellar activity.
Magnetic reconnection produces fast electrons that hit the stellar
surface to produce chromospheric material evaporation. Non-thermal
heating shows up as impulsive flares in optical and hard X-rays, and
evaporation as longer soft X-ray flares. Multi-band observations
covering thermal and non-thermal components are essential to
understand the physics of flaring. The CoRoT space telescope will
continuously observe the star forming region NGC2264 for 20 days in
March 2008 in the optical with unprecedented photometric precision and
with a temporal resolution of 10s of sec, ideal for the detection of
impulsive events. We ask for two 100ksec observations in the two most
populated cluster regions during the CoRoT observation to
simultaneously study the non-thermal (CoRoT) and the thermal (Chandra)
components of flares. 100s of flaring sources have already been
detected in a single ACIS field in NGC2264 (Flaccomio et al. 2006).

Sequence Number: 200526

Title : The physics of flares in young stellar objects
PI: Micela
Abstract: Flares are the most extreme manifestation of stellar activity.
Magnetic reconnection produces fast electrons that hit the stellar
surface to produce chromospheric material evaporation. Non-thermal
heating shows up as impulsive flares in optical and hard X-rays, and
evaporation as longer soft X-ray flares. Multi-band observations
covering thermal and non-thermal components are essential to
understand the physics of flaring. The CoRoT space telescope will
continuously observe the star forming region NGC2264 for 20 days in
March 2008 in the optical with unprecedented photometric precision and
with a temporal resolution of 10s of sec, ideal for the detection of
impulsive events. We ask for two 100ksec observations in the two most
populated cluster regions during the CoRoT observation to
simultaneously study the non-thermal (CoRoT) and the thermal (Chandra)
components of flares. 100s of flaring sources have already been
detected in a single ACIS field in NGC2264 (Flaccomio et al. 2006).

Sequence Number: 100071

Title : Utilizing the exceptional outburst of Comet 17P/Holmes for probing the
solar wind at 2.5 AU
PI: Dennerl
Abstract: We propose to utilize the extreme outburst of Comet 17P/Holmes for
novel X-ray studies with Chandra. Due to the nature of the outburst,
we expect the gas coma to be collisionally thick to charge exchange,
providing the maximum surface brightness. At a heliocentric distance
of 2.5 AU, 1.0 AU more than any other comet observed with Chandra, it
will not only allow us to probe the solar wind at a far distance, but
it will also provide an unprecedented viewing geometry - we will see
the comet from almost the direction as the incident solar wind. Thus,
by utilizing the high spatial resolution of Chandra, it should be
possible to explore the spectral evolution across the face of the
coma. The ecliptic latitude of the comet is 19 deg, so that there is a
possibility that this will become the first Chandra observation of a
comet which is interacting with the polar solar wind or in the
transition zone between the ecliptic and polar winds.

Sequence Number: 100071

Title : Utilizing the exceptional outburst of Comet 17P/Holmes for probing the
solar wind at 2.5 AU
PI: Dennerl
Abstract: We propose to utilize the extreme outburst of Comet 17P/Holmes for
novel X-ray studies with Chandra. Due to the nature of the outburst,
we expect the gas coma to be collisionally thick to charge exchange,
providing the maximum surface brightness. At a heliocentric distance
of 2.5 AU, 1.0 AU more than any other comet observed with Chandra, it
will not only allow us to probe the solar wind at a far distance, but
it will also provide an unprecedented viewing geometry - we will see
the comet from almost the direction as the incident solar wind. Thus,
by utilizing the high spatial resolution of Chandra, it should be
possible to explore the spectral evolution across the face of the
coma. The ecliptic latitude of the comet is 19 deg, so that there is a
possibility that this will become the first Chandra observation of a
comet which is interacting with the polar solar wind or in the
transition zone between the ecliptic and polar winds.

Sequence Number: 100071

Title : Utilizing the exceptional outburst of Comet 17P/Holmes for probing the
solar wind at 2.5 AU
PI: Dennerl
Abstract: We propose to utilize the extreme outburst of Comet 17P/Holmes for
novel X-ray studies with Chandra. Due to the nature of the outburst,
we expect the gas coma to be collisionally thick to charge exchange,
providing the maximum surface brightness. At a heliocentric distance
of 2.5 AU, 1.0 AU more than any other comet observed with Chandra, it
will not only allow us to probe the solar wind at a far distance, but
it will also provide an unprecedented viewing geometry - we will see
the comet from almost the direction as the incident solar wind. Thus,
by utilizing the high spatial resolution of Chandra, it should be
possible to explore the spectral evolution across the face of the
coma. The ecliptic latitude of the comet is 19 deg, so that there is a
possibility that this will become the first Chandra observation of a
comet which is interacting with the polar solar wind or in the
transition zone between the ecliptic and polar winds.

Sequence Number: 900737

Title : The Chandra Deep Field-South Survey: A Public Chandra Legacy
PI: Tananbaum
Abstract: Director's Discretionary observation to increase the exposure on the
CDFS from 1Msec to 2 Msec

Sequence Number: 900737

Title : The Chandra Deep Field-South Survey: A Public Chandra Legacy
PI: Tananbaum
Abstract: Director's Discretionary observation to increase the exposure on the
CDFS from 1Msec to 2 Msec

Sequence Number: 900737

Title : The Chandra Deep Field-South Survey: A Public Chandra Legacy
PI: Tananbaum
Abstract: Director's Discretionary observation to increase the exposure on the
CDFS from 1Msec to 2 Msec

Sequence Number: 400928

Title : Which M15 X-ray Source Brightened?
PI: Heinke
Abstract: We have recently discovered, in archival data, a very faint X-ray
transient in M15 (2004 and 1994 outbursts at ~5e33 ergs/s), in
addition to the two known bright LMXBs. We have just become aware that
the RXTE ASM has recently (June-July) registered an outburst from M15
(=X2127+119), with countrates reaching 4 times normal. 3-4 smaller
outbursts have been seen by RXTE, but this is the brightest yet seen.
Both M15 persistent LMXBs show stable mass transfer. We suspect that
the recent outburst may be due to a third source, possibly the newly
identified transient, or perhaps another source. We request a short
10-ksec HRC-I observation of M15 sometime over the next 10 days to
identify if another X-ray source, besides the two bright LMXBs, is
responsible for the recent brightening of M15. This will give at least
5 counts from all sources with Lx(0.5-10)>2.6e32 ergs/s (for photon
index 1.7).

Sequence Number: 501009

Title : A radio and X-ray study of Type Ic SN2007gr at < 10 Mpc
PI: Soderberg
Abstract: The new Type Ic SN2007gr at just 10 Mpc was spectroscopically
identified on Aug 16 2007 at an estimated age of a few days since
explosion. Our radio follow-up on Aug 17 shows a radio transient
coincident with the optical position. Simultaneous radio (synchrotron)
and X-ray (synchrotron,thermal,and/or IC) observations of SNe Ibc
trace the interaction of the fastest ejecta with the circumstellar
material and have been limited to just a handful of events to date.
The combination of radio and X-ray data breaks model degeneracies and
enables the parameters of the fastest ejecta to be revealed.
Extrapolating the optically thin radio emission as nu^-0.7 to the
X-ray band we expect at a count rate of roughly 0.0005 cps. We
therefore request 20 ksec of DDT within 1-2 weeks for our radio/X-ray
study of this very nearby SN.

Sequence Number: 900737

Title : The Chandra Deep Field-South Survey: A Public Chandra Legacy
PI: Tananbaum
Abstract: Director's Discretionary observation to increase the exposure on the
CDFS from 1Msec to 2 Msec

Sequence Number: 900737

Title : The Chandra Deep Field-South Survey: A Public Chandra Legacy
PI: Tananbaum
Abstract: Director's Discretionary observation to increase the exposure on the
CDFS from 1Msec to 2 Msec

Sequence Number: 900737

Title : The Chandra Deep Field-South Survey: A Public Chandra Legacy
PI: Tananbaum
Abstract: Director's Discretionary observation to increase the exposure on the
CDFS from 1Msec to 2 Msec

Sequence Number: 900737

Title : The Chandra Deep Field-South Survey: A Public Chandra Legacy
PI: Tananbaum
Abstract: Director's Discretionary observation to increase the exposure on the
CDFS from 1Msec to 2 Msec

Sequence Number: 900737

Title : The Chandra Deep Field-South Survey: A Public Chandra Legacy
PI: Tananbaum
Abstract: Director's Discretionary observation to increase the exposure on the
CDFS from 1Msec to 2 Msec

Sequence Number: 900737

Title : The Chandra Deep Field-South Survey: A Public Chandra Legacy
PI: Tananbaum
Abstract: Director's Discretionary observation to increase the exposure on the
CDFS from 1Msec to 2 Msec

Sequence Number: 900737

Title : The Chandra Deep Field-South Survey: A Public Chandra Legacy
PI: Tananbaum
Abstract: Director's Discretionary observation to increase the exposure on the
CDFS from 1Msec to 2 Msec

Sequence Number: 900737

Title : The Chandra Deep Field-South Survey: A Public Chandra Legacy
PI: Tananbaum
Abstract: Director's Discretionary observation to increase the exposure on the
CDFS from 1Msec to 2 Msec

Sequence Number: 900737

Title : The Chandra Deep Field-South Survey: A Public Chandra Legacy
PI: Tananbaum
Abstract: Director's Discretionary observation to increase the exposure on the
CDFS from 1Msec to 2 Msec

Sequence Number: 400691

Title : RFO with Chandra of the newly discovered Millisecond X-ray Pulsar
(MsXP) SWIFT J1756.9-2508
PI: Di Salvo
Abstract: According to the recycling scenario MsXPs are the progenitors of radio
ms pulsars.The recent discovery of the 5.5ms pulsar in the X-ray
transient SWIFT J1756.9-2508(ATEL #1108)brought to 8 the number of
sources of this class.Timing techniques applied to high temporal
resolution data allows the direct measurement of the rotational
behavior of the compact object under the effect of accretion,leading
to an unique opportunity to answer to the long lasting dispute about
accretion models for fast rotators(Burderi 2006,ApJL,653,133;Burderi
2007,ApJ,657,961(BD);Papitto 2007,MNRAS,375,971).However timing
analysis is able to produce reliable results only when an accurate
position of the source is known(BD).The excellent Chandra spatial
resolution will provide an unique accuracy on this key
parameter(Krauss 2005,ApJ,627,910(KR))to further investigate the
rotational behavior of these objects.Chandra will also give us the
possibility to study a high energy resolution spectrum of this
source.

Sequence Number: 400690

Title : Observing flaring activity in the new source SWIFT J195509.6+261406
PI: KANBACH
Abstract: SWIFT/BAT triggered on a new source on 10 June, 2007 20:52:26 UTC
(GCN# 6489, Pagani et al.). The reported position was promptly
observed in optical light and, after some delay, with the XRT. Bright
short optical outbursts (10s timescales, amplitudes >3 mag) were
discovered in the first hour after the trigger and again during the
night June 11-12, 2007 (GCN# 6492,6508, Stefanescu et al.). SWIFT/XRT
confirmed the position of the optical counterpart and the flaring
behaviour (amplitudes up to 25 mCrab). We propose to perform CXO-HETG
spectroscopy of the source to determine the emission process through
the spectrum, and thus the nature of this object. It could be a fast,
giant X-ray transient, SGR or AXP, or a thermonuclear X-ray burster.

Sequence Number: 400689

Title : X-ray jets in CirX-1
PI: Jonker
Abstract: CirX-1 is a neutron star (Tennant et al 1986a,b). The X-ray and radio
flux of CirX-1 have gradually decayed over the last few years.
Recently the radio flux has increased dramatically (ATel 985). The
source has returned to the low X-ray-flux high radio-flux state as
found in the 1970-80ties. On March 6 Fender observed a radio jet using
ATCA at 2" from the core. Interestingly, the position angle of the
radio jet has changed. The large radio flares suggest that major
ejection events take place. We propose a 50 ksec HRC-I observation to
take advantage of the current favorable source/jet count rate ratio to
search for an X-ray counterpart to the new radio jet emission. We
assumed that the X-ray flux and spectrum of a jet is the same as the
X-ray jet observed in XTE J1550-564. For the X-ray flux of CirX-1 we
took the value from our SWIFT-XRT ToO observation of March 19. We
simulated with ChaRT/marx that even a jet placed at a distance of
0.75" is detectable.

Sequence Number: 400688

Title : X-ray jets in CirX-1
PI: Jonker
Abstract: CirX-1 is a neutron star (Tennant et al 1986a,b). The X-ray and radio
flux of CirX-1 have gradually decayed over the last few years.
Recently the radio flux has increased dramatically (ATel 985). The
source has returned to the low X-ray-flux high radio-flux state as
found in the 1970-80ties. On March 6 Fender observed a radio jet using
ATCA at 2" from the core. Interestingly, the position angle of the
radio jet has changed. The large radio flares suggest that major
ejection events take place. We propose a 50 ksec HRC-I observation to
take advantage of the current favorable source/jet count rate ratio to
search for an X-ray counterpart to the new radio jet emission. We
assumed that the X-ray flux and spectrum of a jet is the same as the
X-ray jet observed in XTE J1550-564. For the X-ray flux of CirX-1 we
took the value from our SWIFT-XRT ToO observation of March 19. We
simulated with ChaRT/marx that even a jet placed at a distance of
0.75" is detectable.

Sequence Number: 600649

Title : Constraining the Geometry and Energetics of the Exceptionally
Energetic GRB070125
PI: Frail
Abstract: The IPN and Swift-localized GRB070125, the brightest radio afterglow
seen in almost four years, exhibits a steep spectrum from GHz
frequencies up to ~1 mm, indicating a dense local environment (n >~
100 cm^-3) and an extreme isotropic-equivalent afterglow energy
(~10^54 erg). Depending solely on the angle of collimation (i.e. "jet
opening angle") derived for this burst, it may easily become the
highest-energy release GRB seen to date, straining the capacity of
collapsar models and sounding the death knell for the "standard energy
reservoir" of GRBs (Frail et al., ApJ, 562, 2001). We have an
extensive set of optical and radio data for this burst that show a
likely jet break at t~5 days; at this same epoch, the X-ray afterglow
fades below the detection limit of Swift. We request a single 30-ksec
observation with Chandra to distinguish jet-break from no-break models
for the X-ray emission, and therefore to enable measurement of the
prompt and afterglow energies for this remarkable event.

Sequence Number: 500822

Title : Localization of SN 2005kd
PI: Pooley
Abstract: We propose to observe the Type IIn (narrow emission line) SN 2005kd. A
recent optical spectrum shows it is similar to the extremely X-ray
luminous SN 1988Z (in fact, it has a higher eq. width of H\alpha than
88Z did at a similar epoch). A recent Swift observation detected
emission consistent with the SN at Lx = 1.4e41 erg/s (d=61.5 Mpc).
Because the SN is only 5" from the nucleus of its host galaxy, and
because there may be ULXs also present in the host, we would like to
determine the amount of "contamination" in the Swift emission to the
10% level. In 3ks, we will detect ~75 counts from 05kd, and ~7 counts
from something that's 10% the flux. This will allow a conclusive
association of the Swift source with the SN, as well as provide a
measure of possible contaminating sources. We also plan on proposing
for a deep XMM observation to obtain a high quality spectrum (it will
be visible in a few weeks), and in this case as well, a measure of
contamination will be invaluable.

Sequence Number: 701583

Title : Short Timescale X-ray Variability in the M87 Jet: the TeV connection
PI: Harris
Abstract: The recent interpretation of TeV observations of M87 (Aharonian, 2006
Sci. 314, 1424) hinged on the conventional perception that variability
of a few days requires extremely small emitting volumes which can only
be found close to the nuclear black hole. So in spite of the agreement
in lightcurve peaks (X-ray HST-1 and TeV whole source), the HESS group
argued that the TeV emission originated close to the SMBH rather than
at the distance of HST-1, 200 pc (deproj) from the nucleus. This
proposal requests 8 observations of 5ks each, to measure amplitudes of
X-ray variability of HST-1 and the nucleus for intervals of 3 to 20
days. We already know that HST-1 manifests 2 of the defining
characteristics of blazars: a broad-band intensity flare (factor of
50) and the launching of superluminal radio components. Determination
of which component of M87 has the larger amplitude for day time scale
variability will test the current TeV blazar model and assess the need
for a new blazar paradigm.

Sequence Number: 701582

Title : Short Timescale X-ray Variability in the M87 Jet: the TeV connection
PI: Harris
Abstract: The recent interpretation of TeV observations of M87 (Aharonian, 2006
Sci. 314, 1424) hinged on the conventional perception that variability
of a few days requires extremely small emitting volumes which can only
be found close to the nuclear black hole. So in spite of the agreement
in lightcurve peaks (X-ray HST-1 and TeV whole source), the HESS group
argued that the TeV emission originated close to the SMBH rather than
at the distance of HST-1, 200 pc (deproj) from the nucleus. This
proposal requests 8 observations of 5ks each, to measure amplitudes of
X-ray variability of HST-1 and the nucleus for intervals of 3 to 20
days. We already know that HST-1 manifests 2 of the defining
characteristics of blazars: a broad-band intensity flare (factor of
50) and the launching of superluminal radio components. Determination
of which component of M87 has the larger amplitude for day time scale
variability will test the current TeV blazar model and assess the need
for a new blazar paradigm.

Sequence Number: 701581

Title : Short Timescale X-ray Variability in the M87 Jet: the TeV connection
PI: Harris
Abstract: The recent interpretation of TeV observations of M87 (Aharonian, 2006
Sci. 314, 1424) hinged on the conventional perception that variability
of a few days requires extremely small emitting volumes which can only
be found close to the nuclear black hole. So in spite of the agreement
in lightcurve peaks (X-ray HST-1 and TeV whole source), the HESS group
argued that the TeV emission originated close to the SMBH rather than
at the distance of HST-1, 200 pc (deproj) from the nucleus. This
proposal requests 8 observations of 5ks each, to measure amplitudes of
X-ray variability of HST-1 and the nucleus for intervals of 3 to 20
days. We already know that HST-1 manifests 2 of the defining
characteristics of blazars: a broad-band intensity flare (factor of
50) and the launching of superluminal radio components. Determination
of which component of M87 has the larger amplitude for day time scale
variability will test the current TeV blazar model and assess the need
for a new blazar paradigm.

Sequence Number: 701580

Title : Short Timescale X-ray Variability in the M87 Jet: the TeV connection
PI: Harris
Abstract: The recent interpretation of TeV observations of M87 (Aharonian, 2006
Sci. 314, 1424) hinged on the conventional perception that variability
of a few days requires extremely small emitting volumes which can only
be found close to the nuclear black hole. So in spite of the agreement
in lightcurve peaks (X-ray HST-1 and TeV whole source), the HESS group
argued that the TeV emission originated close to the SMBH rather than
at the distance of HST-1, 200 pc (deproj) from the nucleus. This
proposal requests 8 observations of 5ks each, to measure amplitudes of
X-ray variability of HST-1 and the nucleus for intervals of 3 to 20
days. We already know that HST-1 manifests 2 of the defining
characteristics of blazars: a broad-band intensity flare (factor of
50) and the launching of superluminal radio components. Determination
of which component of M87 has the larger amplitude for day time scale
variability will test the current TeV blazar model and assess the need
for a new blazar paradigm.

Sequence Number: 701579

Title : Short Timescale X-ray Variability in the M87 Jet: the TeV connection
PI: Harris
Abstract: The recent interpretation of TeV observations of M87 (Aharonian, 2006
Sci. 314, 1424) hinged on the conventional perception that variability
of a few days requires extremely small emitting volumes which can only
be found close to the nuclear black hole. So in spite of the agreement
in lightcurve peaks (X-ray HST-1 and TeV whole source), the HESS group
argued that the TeV emission originated close to the SMBH rather than
at the distance of HST-1, 200 pc (deproj) from the nucleus. This
proposal requests 8 observations of 5ks each, to measure amplitudes of
X-ray variability of HST-1 and the nucleus for intervals of 3 to 20
days. We already know that HST-1 manifests 2 of the defining
characteristics of blazars: a broad-band intensity flare (factor of
50) and the launching of superluminal radio components. Determination
of which component of M87 has the larger amplitude for day time scale
variability will test the current TeV blazar model and assess the need
for a new blazar paradigm.

Sequence Number: 701578

Title : Short Timescale X-ray Variability in the M87 Jet: the TeV connection
PI: Harris
Abstract: The recent interpretation of TeV observations of M87 (Aharonian, 2006
Sci. 314, 1424) hinged on the conventional perception that variability
of a few days requires extremely small emitting volumes which can only
be found close to the nuclear black hole. So in spite of the agreement
in lightcurve peaks (X-ray HST-1 and TeV whole source), the HESS group
argued that the TeV emission originated close to the SMBH rather than
at the distance of HST-1, 200 pc (deproj) from the nucleus. This
proposal requests 8 observations of 5ks each, to measure amplitudes of
X-ray variability of HST-1 and the nucleus for intervals of 3 to 20
days. We already know that HST-1 manifests 2 of the defining
characteristics of blazars: a broad-band intensity flare (factor of
50) and the launching of superluminal radio components. Determination
of which component of M87 has the larger amplitude for day time scale
variability will test the current TeV blazar model and assess the need
for a new blazar paradigm.

Sequence Number: 701577

Title : Short Timescale X-ray Variability in the M87 Jet: the TeV connection
PI: Harris
Abstract: The recent interpretation of TeV observations of M87 (Aharonian, 2006
Sci. 314, 1424) hinged on the conventional perception that variability
of a few days requires extremely small emitting volumes which can only
be found close to the nuclear black hole. So in spite of the agreement
in lightcurve peaks (X-ray HST-1 and TeV whole source), the HESS group
argued that the TeV emission originated close to the SMBH rather than
at the distance of HST-1, 200 pc (deproj) from the nucleus. This
proposal requests 8 observations of 5ks each, to measure amplitudes of
X-ray variability of HST-1 and the nucleus for intervals of 3 to 20
days. We already know that HST-1 manifests 2 of the defining
characteristics of blazars: a broad-band intensity flare (factor of
50) and the launching of superluminal radio components. Determination
of which component of M87 has the larger amplitude for day time scale
variability will test the current TeV blazar model and assess the need
for a new blazar paradigm.

Sequence Number: 701576

Title : Short Timescale X-ray Variability in the M87 Jet: the TeV connection
PI: Harris
Abstract: The recent interpretation of TeV observations of M87 (Aharonian, 2006
Sci. 314, 1424) hinged on the conventional perception that variability
of a few days requires extremely small emitting volumes which can only
be found close to the nuclear black hole. So in spite of the agreement
in lightcurve peaks (X-ray HST-1 and TeV whole source), the HESS group
argued that the TeV emission originated close to the SMBH rather than
at the distance of HST-1, 200 pc (deproj) from the nucleus. This
proposal requests 8 observations of 5ks each, to measure amplitudes of
X-ray variability of HST-1 and the nucleus for intervals of 3 to 20
days. We already know that HST-1 manifests 2 of the defining
characteristics of blazars: a broad-band intensity flare (factor of
50) and the launching of superluminal radio components. Determination
of which component of M87 has the larger amplitude for day time scale
variability will test the current TeV blazar model and assess the need
for a new blazar paradigm.

Sequence Number: 500821

Title : Confirmation of a new Isolated Neutron Star in the ROSAT All Sky
Survey
PI: Rutledge
Abstract: The 7 known X-ray dim isolated neutron stars (INSs) were all
discovered from the ROSAT all-sky survey between 1995 and 1999. We may
have discovered an important one: the first INS in the halo. 1RXS
J1412+7922 is important because: (1) its blackbody spectrum is hotter
than any known INS (235+/-45 eV; compared with 118+/-13 for the next
hottest); (2) its low flux (0.05 PSPC c/s) and high temperature make
it the most distant known INS (8.2 kpc, compared with 2.3 kpc for RX
J0806-4123; the remaining six are <1 kpc); and (3) its high galactic
latitude gives it a galactocentric position (R_c=13.4, z=4.9 kpc) in
the galactic halo. J1412 cannot be powered by accretion (no ISM in the
halo); if cooling, it must be <1e6 yr old, giving a velocity of >4900
km/sec (from the Galactic plane), the highest ever observed.
Otherwise, a cooling time of >1e7 yrs is required, the longest ever
observed.

Sequence Number: 500820

Title : Repudiation or Confirmation of an Enormous Glitch in a Magnetar
PI: Woods
Abstract: On Sep 21, 2006, a bright X-ray burst was recorded (GCN 5581) from the
newly discovered AXP CXO J1647-45. The burst was accompanied by a
large flux increase, spectral hardening, a dramatic pulse profile
change, and a reported glitch of dnu/nu ~1e-4 (ATEL 932) whose
amplitude is unprecedented for any neutron star. Using 4 CXO
observations between 9/27 and 10/28, we have been able to track the
spectral changes, pulse morphology evolution, and provide the first
measurement of the spin-down rate and thus magnetic field strength of
CXO J1647-45 (ATEL 929). Further analysis of all available X-ray data
has brought into question the reality of the reported glitch. The
parameters of this glitch factor heavily into the physical
interpretation of the outburst and in general, our understanding of
the internal structure of magnetars. We are requesting one additional
observation to extend our phase-coherent timing solution to confirm
the measured spin-down rate and better anchor our ephemeris.

Sequence Number: 500817

Title : Accurate position measurement of the Isolated Neutron Star RBS1774
PI: Zane
Abstract: We request a 1ks DDT pointing of the Isolated Neutron Star (INS)
RBS1774, to obtain an accurate determination of the X-ray position.
Position measurements of INSs are of paramount importance for an exact
identification of the optical counterpart: it provides vital
information on the SED, on the cause of the X-ray emission, and, over
a longer term, paves the way to the determination of proper motion and
distance; providing crucial informations on the INS surface
temperature and magnetic field distribution, kick velocity and
energetics, which are still largely unknown. We have recently observed
the RBS1774 field with the VLT, the Magellan telescope and with Keck.
Several sources appear in the XMM error box of the INS and even more
are expected to be detected by deeper VLT images, just requested, that
will push the detection limit down to a V=28. A Chandra HRC-I accurate
position is necessary to reliably determine RBS1774 counterpart.

Sequence Number: 200460

Title : A(nother) Star is Born: the Early Evolution of a Pre-main Sequence
Accretion Burst
PI: Kastner
Abstract: Accretion processes produce X-ray emission in a wide variety of
astrophysical environments, yet the link between pre-main sequence
(PMS) star accretion and X-ray emission remains tenuous at best.
Undoubtedly the most convincing example of accretion-driven PMS X-ray
emission is that of V1647 Ori; Chandra observations obtained over the
(two-year) duration of the optical/IR outburst of this PMS star
revealed that its X-ray flux and hardness closely tracked the dramatic
rise and subsequent decline of its accretion luminosity (Kastner et
al. 2004, Nature, 430, 429 and 2006, ApJ, 648, L43). These results for
V1647 Ori suggest that X-ray emission from erupting low-mass, PMS
stars is diagnostic of the degree of star-disk magnetic field
reorganization during major ("FUor"- or "EXor"-type) accretion events.
Prompt post-outburst observations of additional erupting PMS stars are
required to test this hypothesis.

Sequence Number: 500816

Title : The Extreme Supernova 2006gy
PI: Pooley
Abstract: We propose to observe the Type IIn (narrow emission line) SN 2006gy in
NGC 1260. Its optical spectrum (CBET/IAUC submitted) show it is
similar to the extremely X-ray luminous SN 1988Z, which was observed
at Lx=10^41 erg/s at an age of 6.5 yr. It is unknown what the
early-time (first few weeks to months) Lx of such a SN would be. Past
attempts at early X-ray detections (2005bx, 2005db) have given only
upper limits (but follow-ups have been approved), but the class is
likely not homogenous. The extreme optical luminosity (M_V = -22)
makes this SN stand out even among the IIn's (an already unusual class
of objects). The astrometry will be crucial to resolving the SN from
possible nuclear activity. Two X-ray sources within 2.5 arcmin of
2006gy (found in ObsID 5597) have 2MASS counterparts. They have fluxes
of 5.1e-15 and 2.1e-14 (cgs). Our request of 30 ks is based on
localizing these sources well enough (getting 25-30 cts) to achieve
~<0.2" X-ray/2MASS astrometry.

Sequence Number: 500815

Title : X-Ray Emission from the Type Ib SN 2006jc
PI: Immler
Abstract: An X-ray source is detected at the position of the SN in a 3.4 ks
Swift XRT obs from 2006-10-13 16:10 UT with a flux and lum of
1.0+/-0.4 E-13 ergs/cm/cm/s and 6.7+/-2.7 E39 ergs/s (0.2-10 keV). The
UV-V colors are extremely blue, similar to the X-ray bright SN IIP
2006bp. The Swift UVOT data show that the SN is very bright in the opt
and especially in the UV (ATel 916), likely a result of the shock
interaction with dense CSM, confirming that the X-rays are due to the
SN. Due to the large PSF of the XRT (18 HPD), and an offset of the SN
of 11" W and 7" S of the host galaxy, UGC 4904, XRT data do not allow
us to unambiguously associate the X-ray source with the SN, even at
higher photon statistics. No further Swift obs will be obtained due to
Sun angle constraints. The RASS shows no X-ray source at the position
of the host galaxy. Therefore, the association of the X-ray source
with the SN is strong and the Chandra obs could establish SNe Ib, for
the first time, as X-ray sources.

Sequence Number: 500814

Title : Monitoring a Recovering AXP and Measuring Pdot
PI: Kaspi
Abstract: Anomalous X-ray Pulsar (AXP) outbursts are rare, occuring roughly once
per decade per src, and offer rare opportunities to constrain the
poorly understood physics of magnetars. Recently AXP CXO
164710.2-455216.9 went into outburst and we were granted 3 ToO obs
with CXO. These obs together, via phase-coherent timing, set the best
constraint on the unknown Pdot, which implies magnetic field (3sig)
<2e14 G. This is low for a magnetar but not yet a problem. We request
1 more 25 ks DDT obs of AXP CXO 164710.2-455216.9. This obs will
continue to monitor it back to quiescence to distinguish between
proposed recovery models, and, importantly, if scheduled near Oct 30,
will either detect or put an unprecedented upper limit on Pdot, via
phase connection with previous CXO ToO obs. If no Pdot is detected, we
will constrain B<5e13G (3sig), lower than for any other known magnetar
(lowest known 6e13G), and perplexingly below B measured for some
ordinary, non-magnetar neutron stars.

Sequence Number: 400680

Title : Probing the true nature of the microquasar candidate LS I +61 303
PI: Perez-Torres
Abstract: The radio-emitting x-ray binary LSI +61 303 has been recently detected
at TeV energies. Two scenarios have been proposed to account for this
high-energy emission, namely an accretion/jet mechanism (microquasar),
and an interacting pulsar wind model. We propose to observe LSI +61
303 with Chandra as part of a multi-wavelength campaign that includes
simultaneous observations with MAGIC (gamma-rays), MERLIN (radio), and
Calar Alto (infra-red). (Those observations have been approved for the
nights of the 25 and 26 October 2006.) The proposed observations will
be the first such simultaneous, multiwavelength effort on this object,
and the geometrical, spectral and temporal features of its radio
emission will be studied and correlated with those in the infra-red,
X-ray and, TeV regimes. The results will help to elucidate the true
nature of LS I +61 303 and the acceleration mechanisms that produce
the high energy emission.

Sequence Number: 600607

Title : Accurate X-ray position of a possible >10^41 erg/s ULX: evidence for
an intermediate-mass black hole?
PI: Miniutti
Abstract: We have detected with XMM-Newton an off-nuclear ULX candidate in the
D25 ellipse of a spiral galaxy at 90 Mpc. If at 90 Mpc, its 0.5-10 keV
luminosity is 1.3x10^41 erg/s, the most luminous ULX ever detected.
The probability of it being a background AGN is very low based on
standard logN-logS (<0.7%) and even lower if the minimum X-ray to
Optical flux ratio (>60) is considered. The only available HST image
shows several possible counteparts in the XMM error box. We request a
7ks Chandra ACIS-S exposure to measure the X-ray position with high
accuracy, which will allow us to identify the counterpart (if any)
from HST+Chandra and to organize the optimal follow-up strategy. The
Chandra obs by itself may exclude that the ULX is a background AGN if
the HST counterpart is identified, allowing us to compute a precise
X-ra to Optical ratio which, if > 100 (as for the large majority of
possible counterparts), would exclude the AGN hypothesis.

Sequence Number: 400561

Title : Is PSR B1931+24 the golden source for the accretion regimes testing?
PI: Rea
Abstract: Very recently the discovery of an intermittent radio pulsar was
reported on Science (Kramer et al.2006,astro-ph/0604605). PSR B1931+24
has the surprising peculiarity of being a 813ms radio-pulsar for ~5d
and being radio quiet for the following 25-35d, periodically. The
pulsar spin slows down 50% faster when the pulsar is on than when is
off. The ~30d periodicity and the weird spin-down behaviour of this
radio activity remind what is expected for a pulsar in a binary system
spinning near the equilibrium period in an eccentric ~30d orbit: at
the apastron the low wind accretion rate allows the radio pulsar
regime, while at the periastron the neutron star is radio-quiet
because accreting and emitting in the X-rays. This might be the
linking object between the X-ray binaries and the radio pulsar
binaries, a golden source for finally testing the accretion regimes.

Sequence Number: 100067

Title : An Extremely Close Encounter with the Disintegrating Comet 73P/SW3
PI: Wolk
Abstract: We propose to use the ACIS-S instrument on Chandra to study the X-ray
emission from the fragment B of comet 73P/Schwassmann-Wachmann 3. This
comet is in the act of disintegration and is currently 43 tracked
elements and countless additional pieces as detailed in recent Spitzer
and HST observations. It will also pass closer to the Earth in May
2006 than any comet yet detected in the x-rays. We propose a total of
20 ks observation of fragment B. These data will allow us to spatially
resolve the detailed structure of the interaction zone between the
solar wind and the coma at a spatial resolution of ~75 km, the solar
wind velocity structure in the mass-loading zone at the coma edge. The
interpretation will be simplified relative to previous comets because
ACE/SOHO are almost in front of the comet. We therefore will know the
precise state of the Solar Wind.

Sequence Number: 100066

Title : An Extremely Close Encounter with the Disintegrating Comet 73P/SW3
PI: Wolk
Abstract: We propose to use the ACIS-S instrument on Chandra to study the X-ray
emission from the fragment B of comet 73P/Schwassmann-Wachmann 3. This
comet is in the act of disintegration and is currently 43 tracked
elements and countless additional pieces as detailed in recent Spitzer
and HST observations. It will also pass closer to the Earth in May
2006 than any comet yet detected in the x-rays. We propose a total of
20 ks observation of fragment B. These data will allow us to spatially
resolve the detailed structure of the interaction zone between the
solar wind and the coma at a spatial resolution of ~75 km, the solar
wind velocity structure in the mass-loading zone at the coma edge. The
interpretation will be simplified relative to previous comets because
ACE/SOHO are almost in front of the comet. We therefore will know the
precise state of the Solar Wind.

Sequence Number: 100065

Title : An Extremely Close Encounter with the Disintegrating Comet 73P/SW3
PI: Wolk
Abstract: We propose to use the ACIS-S instrument on Chandra to study the X-ray
emission from the fragment B of comet 73P/Schwassmann-Wachmann 3. This
comet is in the act of disintegration and is currently 43 tracked
elements and countless additional pieces as detailed in recent Spitzer
and HST observations. It will also pass closer to the Earth in May
2006 than any comet yet detected in the x-rays. We propose a total of
20 ks observation of fragment B. These data will allow us to spatially
resolve the detailed structure of the interaction zone between the
solar wind and the coma at a spatial resolution of ~75 km, the solar
wind velocity structure in the mass-loading zone at the coma edge. The
interpretation will be simplified relative to previous comets because
ACE/SOHO are almost in front of the comet. We therefore will know the
precise state of the Solar Wind.

Sequence Number: 100064

Title : An Extremely Close Encounter with the Disintegrating Comet 73P/SW3
PI: Wolk
Abstract: We propose to use the ACIS-S instrument on Chandra to study the X-ray
emission from the fragment B of comet 73P/Schwassmann-Wachmann 3. This
comet is in the act of disintegration and is currently 43 tracked
elements and countless additional pieces as detailed in recent Spitzer
and HST observations. It will also pass closer to the Earth in May
2006 than any comet yet detected in the x-rays. We propose a total of
20 ks observation of fragment B. These data will allow us to spatially
resolve the detailed structure of the interaction zone between the
solar wind and the coma at a spatial resolution of ~75 km, the solar
wind velocity structure in the mass-loading zone at the coma edge. The
interpretation will be simplified relative to previous comets because
ACE/SOHO are almost in front of the comet. We therefore will know the
precise state of the Solar Wind.

Sequence Number: 100063

Title : An Extremely Close Encounter with the Disintegrating Comet 73P/SW3
PI: Wolk
Abstract: We propose to use the ACIS-S instrument on Chandra to study the X-ray
emission from the fragment B of comet 73P/Schwassmann-Wachmann 3. This
comet is in the act of disintegration and is currently 43 tracked
elements and countless additional pieces as detailed in recent Spitzer
and HST observations. It will also pass closer to the Earth in May
2006 than any comet yet detected in the x-rays. We propose a total of
20 ks observation of fragment B. These data will allow us to spatially
resolve the detailed structure of the interaction zone between the
solar wind and the coma at a spatial resolution of ~75 km, the solar
wind velocity structure in the mass-loading zone at the coma edge. The
interpretation will be simplified relative to previous comets because
ACE/SOHO are almost in front of the comet. We therefore will know the
precise state of the Solar Wind.

Sequence Number: 300179

Title : CHANDRA Observations of RS Oph a Recurrent Symbiotic Nova in Outburst
PI: Starrfield
Abstract: RS Oph is a Symbiotic Recurrent Nova that was last seen in outburst in
1985. We have been monitoring its X-ray evolution with SWIFT and
obtained a HETG spectrum on 26 February UT. The spectrum is well
exposed although the 0th order is piled up. We are following a shock
caused by material ejected from off a white dwarf and moving at speeds
exceeding one thousand km/sec through the outer layers of a red giant.
It is clearly bright enough for CHANDRA and is evolving rapidly as
evidenced by our SWIFT observations. We will continue to obtain SWIFT
observations (PI M. Bode) more often than the CHANDRA observations. T.
O'Brien is doing hydrodynamic modeling of this outburst to better
understand the evolution of the shock. The presence of emission lines
will allow us to obtain abundances and the line profiles differ which
suggests that the material has not been ejected spherically.

Sequence Number: 300178

Title : CHANDRA Observations of RS Oph a Recurrent Symbiotic Nova in Outburst
PI: Starrfield
Abstract: RS Oph is a Symbiotic Recurrent Nova that was last seen in outburst in
1985. We have been monitoring its X-ray evolution with SWIFT and
obtained a HETG spectrum on 26 February UT. The spectrum is well
exposed although the 0th order is piled up. We are following a shock
caused by material ejected from off a white dwarf and moving at speeds
exceeding one thousand km/sec through the outer layers of a red giant.
It is clearly bright enough for CHANDRA and is evolving rapidly as
evidenced by our SWIFT observations. We will continue to obtain SWIFT
observations (PI M. Bode) more often than the CHANDRA observations. T.
O'Brien is doing hydrodynamic modeling of this outburst to better
understand the evolution of the shock. The presence of emission lines
will allow us to obtain abundances and the line profiles differ which
suggests that the material has not been ejected spherically.

Sequence Number: 300177

Title : CHANDRA Observations of RS Oph a Recurrent Symbiotic Nova in Outburst
PI: Starrfield
Abstract: RS Oph is a Symbiotic Recurrent Nova that was last seen in outburst in
1985. We have been monitoring its X-ray evolution with SWIFT and
obtained a HETG spectrum on 26 February UT. The spectrum is well
exposed although the 0th order is piled up. We are following a shock
caused by material ejected from off a white dwarf and moving at speeds
exceeding one thousand km/sec through the outer layers of a red giant.
It is clearly bright enough for CHANDRA and is evolving rapidly as
evidenced by our SWIFT observations. We will continue to obtain SWIFT
observations (PI M. Bode) more often than the CHANDRA observations. T.
O'Brien is doing hydrodynamic modeling of this outburst to better
understand the evolution of the shock. The presence of emission lines
will allow us to obtain abundances and the line profiles differ which
suggests that the material has not been ejected spherically.

Sequence Number: 300172

Title : CHANDRA Observations of RS Oph a Recurrent Symbiotic Nova in Outburst
PI: Starrfield
Abstract: RS Oph is a Symbiotic Recurrent Nova that was last seen in outburst in
1985 It was observed by EXOSAT. It's outburst commenced on Jan. 26
(IAUC 4030, 4031, 4036). EXOSAT observed RS Oph between 18h00 and
23h00 UT on 1985 Mar. 22. Preliminary analysis indicated that the
x-ray spectrum was soft and absorbed. Fits to a thermal bremsstrahlung
model yielded a temperature of 0.75 keV and an absorbing column
density of ~ 10**21 atoms cm**-2. The flux at Earth in the 0.1-6.0-keV
band was estimated to be 4 x 10**-10 erg cm-**2 s**-1. This was taken
from an IAU Circular by Cordova and Mason in 1985. It has an extremely
rapid decline in Xrays which are probably caused by a shock moving
through a red giant atmosphere.

Sequence Number: 500693

Title : Chandra observation of the Type Ia SN 2005ke
PI: Immler
Abstract: The longest Swift obs. obtained to date (258-ksec) on a SN gives
evidence that the Type Ia SN 2005ke has been detected in X-rays, at a
low level of significance (3-3.5 sigma, CBET 387). See
http://lheawww.gsfc.nasa.gov/users/immler/SN2005ke/Immler_fig1.jpg for
Swift UV and XRT X-ray image. No SN Ia has ever been detected in
X-rays. The Swift UVOT UV lightcurve
http://lheawww.gsfc.nasa.gov/users/immler/SN2005ke/Immler_fig3b.jpg
shows a UV excess starting around 35d after the explosion with respect
to SN Ia lightcurve templates, coinciding with the onset of X-ray
emission. The detection of UV excess is independent confirmation that
the X-rays are from the interaction of the SN shock with CSM as the UV
emission is due to the Mg II emission line at 280 nm. We request a
15-ksec Chandra ACIS-S observation of the nearby (20.7 Mpc) Type Ia SN
2005ke to unambigiously associate the detected Swift X-ray source with
the SN.

Sequence Number: 500692

Title : Accurate positioning of four INTEGRAL selected isolated NSs
PI: Israel
Abstract: Based on the newly discovered hard X-ray spectral characteristics of
AXPs and SGRs we selected 4 dim persistent unidentified radio-quiet
INTEGRAL sources with a relatively bright ROSAT source in their
positional uncertainty regions. In the best case we rely upon a ROSAT
HRI position (3" radius position uncertainty) with no clear optical
counterpart down to V~22, making it a very reliable AXP candidate (the
V upper limit excludes 90% of the known LMXBs). However, several tens
of IR sources are expected in a 3" radius circular region on the
Galactic plane. Chandra is currently the only mission able to obtain
source positions with a sub-arcsec accuracy needed to sort out the
right counterparts of the four sources. Already granted GO XMM
observations will be used to look for pulsations, while Optical/IR
observations will be carried out during the next months. The latter
observations would greatly take advantage of the Chandra positions.

Sequence Number: 500691

Title : Accurate positioning of four INTEGRAL selected isolated NSs
PI: Israel
Abstract: Based on the newly discovered hard X-ray spectral characteristics of
AXPs and SGRs we selected 4 dim persistent unidentified radio-quiet
INTEGRAL sources with a relatively bright ROSAT source in their
positional uncertainty regions. In the best case we rely upon a ROSAT
HRI position (3" radius position uncertainty) with no clear optical
counterpart down to V~22, making it a very reliable AXP candidate (the
V upper limit excludes 90% of the known LMXBs). However, several tens
of IR sources are expected in a 3" radius circular region on the
Galactic plane. Chandra is currently the only mission able to obtain
source positions with a sub-arcsec accuracy needed to sort out the
right counterparts of the four sources. Already granted GO XMM
observations will be used to look for pulsations, while Optical/IR
observations will be carried out during the next months. The latter
observations would greatly take advantage of the Chandra positions.

Sequence Number: 500690

Title : Accurate positioning of four INTEGRAL selected isolated NSs
PI: Israel
Abstract: Based on the newly discovered hard X-ray spectral characteristics of
AXPs and SGRs we selected 4 dim persistent unidentified radio-quiet
INTEGRAL sources with a relatively bright ROSAT source in their
positional uncertainty regions. In the best case we rely upon a ROSAT
HRI position (3" radius position uncertainty) with no clear optical
counterpart down to V~22, making it a very reliable AXP candidate (the
V upper limit excludes 90% of the known LMXBs). However, several tens
of IR sources are expected in a 3" radius circular region on the
Galactic plane. Chandra is currently the only mission able to obtain
source positions with a sub-arcsec accuracy needed to sort out the
right counterparts of the four sources. Already granted GO XMM
observations will be used to look for pulsations, while Optical/IR
observations will be carried out during the next months. The latter
observations would greatly take advantage of the Chandra positions.

Sequence Number: 500689

Title : Accurate positioning of four INTEGRAL selected isolated NSs
PI: Israel
Abstract: Based on the newly discovered hard X-ray spectral characteristics of
AXPs and SGRs we selected 4 dim persistent unidentified radio-quiet
INTEGRAL sources with a relatively bright ROSAT source in their
positional uncertainty regions. In the best case we rely upon a ROSAT
HRI position (3" radius position uncertainty) with no clear optical
counterpart down to V~22, making it a very reliable AXP candidate (the
V upper limit excludes 90% of the known LMXBs). However, several tens
of IR sources are expected in a 3" radius circular region on the
Galactic plane. Chandra is currently the only mission able to obtain
source positions with a sub-arcsec accuracy needed to sort out the
right counterparts of the four sources. Already granted GO XMM
observations will be used to look for pulsations, while Optical/IR
observations will be carried out during the next months. The latter
observations would greatly take advantage of the Chandra positions.

Sequence Number: 400559

Title : Searching for the optical/IR counterpart of the transient X-ray pulsar
Swift J1626.6-5156
PI: Homan
Abstract: The transient 15.3 sec X-ray pulsar Swift J1626.6-5156 was discovered
late 2005. It shares some properties with anomalous X-ray pulsars,but
is most likely a 'normal' X-ray pulsar with some unusual properties.
Determining the nature of the companion star could shed light on the
mode of accretion (disk vs. wind), which in turn might help explain
some of the unusual properties. Recent IR observations seem to rule
out a HMXB as the optical counterpart of the source (ATel 713).
Further attempts at identifying the optical counterpart are hampered
by the uncertainty in the position of the source. The most accurate
position has 90% an error circle of ~3.5 arcseconds (ATel 688).
However, reliable counterparts to other X-ray sources