Accepted Cycle 12 Observing Proposals

BH & NS BINARIES

Proposal Number	Subject Category	PI Name	Title
12400113	BH AND NS BINARIES	Miller	High Resolution Spectroscopy of a Black Hole Transient
12400140	BH AND NS BINARIES	Soleri	ToO observations of the microquasar GRS 1915+105 in quiescence
12400154	BH AND NS BINARIES	Patruno	Identifying the nature of the compact object in Swift J1753.5-0127
12400205	BH AND NS BINARIES	Corbel	X-Ray Jets in Microquasars
12400222	BH AND NS BINARIES	Degenaar	Crustal cooling of the neutron star in EXO 0748-676
12400231	BH AND NS BINARIES	Tomsick	The Nature of INTEGRAL Sources in the Galactic Plane
12400242	BH AND NS BINARIES	Degenaar	The crust cooling of HETE J1900.1-2455
12400297	BH AND NS BINARIES	Feng	Optical Counterpart of the ULX in NGC 247
12400346	BH AND NS BINARIES	Jonker	Following a black hole candidate X-ray transient to quiescence
12400372	BH AND NS BINARIES	Galloway	Photospheric radius-expansion bursts at high spectral resolution
12400382	BH AND NS BINARIES	in 't Zand	Search for absorption edges in superexpansion bursts
12400402	BH AND NS BINARIES	Grenier	ToO observation of a bright Galactic transient discovered by Fermi and Swift
12400451	BH AND NS BINARIES	Valencic	X Per: The Template for the Diffuse Interstellar Medium
12400454	BH AND NS BINARIES	Chakrabarty	Precise Localization of Transient Low-Mass X-ray Binaries
12400458	BH AND NS BINARIES	Paizis	INVESTIGATING NEW INTEGRAL SOURCES WITH CHANDRA
12400491	BH AND NS BINARIES	Pooley	Transient LMXBs in Globular Clusters: More Numerous than We Thought?
12400574	BH AND NS BINARIES	Rutledge	Confirmation and Study of a Newly Discovered Nuclear Reaction, Identified in the Neutron Star Crust
12400580	BH AND NS BINARIES	Tanaka	HIGH-RESOLUTION SPECTROSCOPY OF THE PHOTOIONIZED STELLAR WIND OF X-RAY PULSAR OAO 1657
12400656	BH AND NS BINARIES	Heinke	The Unusual X-ray Binaries of the Globular Cluster NGC 6652
12400666	BH AND NS BINARIES	Neilsen	A Long Multiwavelength Study of GRS 1915+105: Accretion/Ejection Physics of the Disk Wind and Radio Jet
12400717	BH AND NS BINARIES	McLaughlin	X-ray observations of a nearby, old Rotating Radio Transient
12400736	BH AND NS BINARIES	Lorimer	Constraining the X-ray spectrum of a nearby unusual binary pulsar
12400740	BH AND NS BINARIES	McLaughlin	First X-ray Observations of Four New Fermi-Associated Black-Widow Pulsars
12400752	BH AND NS BINARIES	Homan	Spectral state dependence of the extended accretion flow components in LMXBs
12400796	BH AND NS BINARIES	Chakrabarty	Validating Neutron Star Radius Measurements
12400823	BH AND NS BINARIES	Reynolds	The Quiescent X-Ray Luminosity of Stellar Mass Black Holes
12400833	BH AND NS BINARIES	Hanke	Filling the gap in understanding the wind structure of HDE 226868 / Cyg X-1
12400837	BH AND NS BINARIES	Yang	Identifying the Optical Counterparts of ULXs in the Blue Compact Dwarf Galaxy NGC 4861 (Mrk 59)
12400869	BH AND NS BINARIES	Pottschmidt	Exposing the symbiosis of 3A 1954+319
12400885	BH AND NS BINARIES	Rutledge	The Nearest and Brightest Quiescent Low Mass X-ray Binaries
12400892	BH AND NS BINARIES	Lutovinov	PRECISE CHANDRA LOCALIZATION OF FAINT PERSISTENT X-RAY SOURCES NEAR THE GALACTIC PLANE
12400915	BH AND NS BINARIES	Bodaghee	Refining the positions of soft gamma-ray sources with Chandra
12400926	BH AND NS BINARIES	Tomsick	Census of the Normal Spiral Arm Region
12400936	BH AND NS BINARIES	Wolff	Searching New Millisecond Pulsar Fields for X-ray Counterparts

Subject Category: BH AND NS BINARIES

Proposal Number: 12400113

Title: High Resolution Spectroscopy of a Black Hole Transient

PI Name: Jon Miller

We propose to continue our ongoing study of Galactic black hole transients in outburst in a streamlined form, via two (2) 30 ksec HETGS observations. This program has revealed relativistic Fe K disk lines, warm-absorber-like disk winds, and now a possible anti-correlation between winds and jets. Observations of a new transient outburst will test connections between disks, winds, and jets, and permit a constraint on the black hole spin parameter. We will support this program with a global multi-wavelength network of observatories.

R.A.	Dec.	Target Name	Det.	Grating	Exp.Time
		Black Hole Transient	ACIS-S	HETG	60

Subject Category: BH AND NS BINARIES

Proposal Number: 12400140

Title: ToO observations of the microquasar GRS 1915+105 in quiescence

PI Name: Paolo Soleri

We propose two Chandra observations (40 ks each) to detect the microquasar GRS 1915+105 in quiescence, should its current 18-year-long outburst end during the 12th Chandra observing cycle. This system has never been observed in quiescence: its properties suggest that its quiescent X-ray luminosity would be rather high (~10^34 erg/s), allowing a measurement of the spectrum and a test of models for quiescent emission in black-hole binaries. In addition, it will be possible to detect a fossil jet similar to that detected in the black hole candidate 4U 1755-33.

R.A.	Dec.	Target Name	Det.	Grating	Exp.Time
19:15:11.60	+10:56:44.00	GRS 1915+105	ACIS-I	NONE	80

Subject Category: BH AND NS BINARIES

Proposal Number: 12400154

Title: Identifying the nature of the compact object in Swift J1753.5-0127

PI Name: Alessandro Patruno

We propose to observe the X-ray binary Swift J1753.5-0127 with a 30 ks observation, should the source end its current 5-year-long outburst. Despite several multi-wavelength monitoring campaigns, the nature of the compact object in the binary is still unknown. The system has been accreting matter at a relatively high rate M_dot~10^{-10} M_Sun/yr for almost 5 years. Current models predict a high quiescence luminosity (~10^{32}-10^{33} erg/s) and clear signatures (thermal emission) of a heated crust, if the binary hosts a neutron star. If the system contains a black hole, such signatures will not be detected and the source will rapidly fade down to its predicted quiescent luminosity (~10^{30} - 10^{31} erg/s).

R.A.	Dec.	Target Name	Det.	Grating	Exp.Time
17:53:28.30	-01:27:09.00	Swift J1753.5-0127	ACIS-S	NONE	30

Subject Category: BH AND NS BINARIES

Proposal Number: 12400205

Title: X-Ray Jets in Microquasars

PI Name: St phane Corbel

We propose Target of Opportunity (ToO) observations for detailed studies of X-ray jets from microquasars. We describe our discovery of radio/X-ray jets in two microquasars, why X-ray jets are probably much more common than previously thought, and transient X-ray jets offer an exciting new way to probe the physics of relativistic jets from black holes. The proposed ToO observations are optimized to discover and study (flux evolution, morphology, SED, proper motion, ...) of new X-ray jets from microquasars, triggered by their detection as radio lobes. This will have implications not only for the study of jets from Galactic X-ray binaries, but also for our understanding of relativistic jets from active galactic nuclei (AGN).

R.A.	Dec.	Target Name	Det.	Grating	Exp.Time
		X-ray Jets	ACIS-S	NONE	150

Subject Category: BH AND NS BINARIES

Proposal Number: 12400222

Title: Crustal cooling of the neutron star in EXO 0748-676

PI Name: Nathalie Degenaar

We propose a single 40-ks Chandra observation to continue our successful monitoring program to study the crust cooling of the neutron star in the quasi-persistent X-ray binary EXO 0748-676. In late 2008, this system started the transition to quiescence following an extended period of accretion that lasted more than 24 years. Studying the thermal relaxation of the accretion-heated neutron star provides the unique opportunity to study its interior properties, as well as the behavior of matter in an extreme density and pressure environment.

R.A.	Dec.	Target Name	Det.	Grating	Exp.Time
07:48:33.80	-67:45:08.60	EXO 0748-676	ACIS-S	NONE	40

Subject Category: BH AND NS BINARIES

Proposal Number: 12400231

Title: The Nature of INTEGRAL Sources in the Galactic Plane

PI Name: John Tomsick

The INTEGRAL satellite is continuing to discover new hard X-ray sources in the Galactic plane. The few arcminute INTEGRAL positions do not allow for identification of these IGR sources at other wavelengths, leaving their nature unclear. Chandra can make a major contribution to studies of IGR sources by localizing the sources to allow for the identification of counterparts and by constraining the soft X-ray spectrum. We propose for relatively short Chandra observations of 19 unidentified IGR sources in the Galactic plane. In previous cycles, this program has identified new High-Mass X-ray Binaries with interesting properties, Catalysmic Variables, and supernova remnants.

R.A.	Dec.	Target Name	Det.	Grating	Exp.Time
16:17:15.40	-50:23:09.60	IGR J16173-5023	ACIS-I	NONE	5
12:48:53.50	-62:43:04.80	IGR J12489-6243	ACIS-I	NONE	5
15:29:15.80	-56:09:46.80	IGR J15293-5609	ACIS-I	NONE	5
21:18:47.80	+49:01:01.20	IGR J21188+4901	ACIS-I	NONE	5
03:10:16.80	+57:06:07.20	IGR J03103+5706	ACIS-I	NONE	5
11:01:21.80	-61:03:21.60	IGR J11014-6103	ACIS-I	NONE	5
04:06:55.20	+50:42:07.20	IGR J04069+5042	ACIS-I	NONE	5
15:39:04.60	-53:06:57.60	IGR J15391-5307	ACIS-I	NONE	5
16:20:35.80	-52:52:58.80	IGR J16206-5253	ACIS-I	NONE	5
13:40:12.00	-64:28:48.00	IGR J13402-6428	ACIS-I	NONE	5
01:54:25.20	+64:37:12.00	IGR J01545+6437	ACIS-I	NONE	5
09:18:55.40	-44:18:43.20	IGR J09189-4418	ACIS-I	NONE	5
16:41:20.90	-40:46:51.60	IGR J16413-4046	ACIS-I	NONE	5
15:36:47.30	-51:02:42.00	IGR J15368-5102	ACIS-I	NONE	5
15:41:28.60	-50:29:27.60	IGR J15415-5029	ACIS-I	NONE	5
21:56:30.20	+59:48:54.00	IGR J21565+5948	ACIS-I	NONE	5
16:55:57.40	-49:58:01.20	IGR J16560-4958	ACIS-I	NONE	5
22:01:26.60	+60:34:01.20	IGR J22014+6034	ACIS-I	NONE	5
06:55:10.10	-11:46:12.00	IGR J06552-1146	ACIS-I	NONE	5

Subject Category: BH AND NS BINARIES

Proposal Number: 12400242

Title: The crust cooling of HETE J1900.1-2455

PI Name: Nathalie Degenaar

We propose a series of three 30-ks Chandra ToO observations of the neutron star quasi-persistent X-ray binary HETE J1900.1-2455 once it returns to quiescence. Currently, the source undergoes an extended episode of accretion that started about 4.5 years ago. Studying the cooling of the accretion heated neutron star once the system returns to quiescence provides an unique opportunity to investigate a variety of processes occurring under extreme density and pressure conditions. Furthermore, since HETE J1900.1-2455 is the only quasi-persistent neutron star X-ray binary currently in outburst from which X-ray pulsations have been detected, this source allows us to test the possible effects of a high magnetic field on the thermal evolution of neutron stars.

R.A.	Dec.	Target Name	Det.	Grating	Exp.Time
19:00:08.70	-24:55:13.70	HETE J1900.1-2455	ACIS-S	NONE	90

Subject Category: BH AND NS BINARIES

Proposal Number: 12400297

Title: Optical Counterpart of the ULX in NGC 247

PI Name: Hua Feng

A recent XMM-Newton observation revealed a highly interesting ultraluminous X-ray source (ULX) in NGC 247. It is similar to Galactic black hole binaries (BHBs) at the thermal dominant state while the cool, ultraluminous disk suggests the presence of an intermediate mass black hole. ULXs are rarely found in the thermal dominant state and this source would provide us a precious laboratory to study the connection between ULXs and Galactic BHBs. We propose Chandra and HST observations of the source to accurately measure its X-ray position, identify a unique optical counterpart, and search for optical nebulosity. Identification of the optical counterpart will help constrain its evolutionary history and physical nature.

R.A.	Dec.	Target Name	Det.	Grating	Exp.Time
00:46:57.80	-20:45:37.60	NGC 247 ULX	ACIS-S	NONE	5

Subject Category: BH AND NS BINARIES

Proposal Number: 12400346

Title: Following a black hole candidate X-ray transient to quiescence

PI Name: Peter Jonker

There is increasing evidence that the quiescent state of BH X-ray binaries is different from the canonical hard state. Our recent Chandra campaigns on BH transient decays suggest that the spectral hardening in the hard state decay stops. This transition has so far not been resolved with enough SN to fully quantify it, but there are strong indications that the spectrum softens during the subsequent decay. We find evidence that the radio - X-ray correlation varies between sources, this is probably caused by radio flares during the decay. Both the spectral evolution and the radio - X-ray correlation can provide important constraints for jet-dominated and ADAF models. We request simultaneous Chandra/EVLA ToO observations. The new EVLA is an asset for the science presented in this proposal.

R.A.	Dec.	Target Name	Det.	Grating	Exp.Time
		TOO	ACIS-S	NONE	187

Subject Category: BH AND NS BINARIES

Proposal Number: 12400372

Title: Photospheric radius-expansion bursts at high spectral resolution

PI Name: Duncan Galloway

It has been predicted that strong (a few hundred eV EW) photoionisation edges might be present in the X-ray spectra at the peak of photospheric radius-expansion thermonuclear bursts, and these predictions have been corroborated recently in low-resolution RXTE spectra. We propose to search for such features in bursts from sources known for frequent radius-expansion bursts. This resubmission of an untriggered AO-10 proposal will result in detection of up to 30 bursts, also allowing detailed comparisons of recurrence time and energetics with numerical ignition models, as well as a high signal-to-noise persistent spectrum. Detection of discrete features from the burst spectra may lead to constraints on the compactness and hence the neutron-star equation of state.

R.A.	Dec.	Target Name	Det.	Grating	Exp.Time
17:38:58.30	-44:27:00.00	4U 1735-44	ACIS-S	HETG	150

Subject Category: BH AND NS BINARIES

Proposal Number: 12400382

Title: Search for absorption edges in superexpansion bursts

PI Name: Jean in 't Zand

Our goal is to measure with the LETGS a series of bright type-I X-ray bursts with strong photospheric radius expansion ('superexpansion'), search for absorption edges due to the ashes of nuclear burning and, if succesful, attempt a measurement of the gravitational redshift. The target, 4U 1820-30, is an ultracompact X-ray binary whose bursts are known to consistently show strong expansion. The bursts only occur in the quasi-periodic low accretion states. We request a quick TOO, to be triggered by either RXTE-ASM or ISS-MAXI, with a total exposure time of 100 ks to obtain the detection of about 10 bursts.

R.A.	Dec.	Target Name	Det.	Grating	Exp.Time
18:23:40.50	-30:21:40.00	4U 1820-30	ACIS-S	LETG	100

Subject Category: BH AND NS BINARIES

Proposal Number: 12400402

Title: ToO observation of a bright Galactic transient discovered by Fermi and Swift

PI Name: Isabelle Grenier

We propose a TOO observation of one bright Galactic transient detected by the Fermi large area telescope, and followed by a Swift-XRT detection. Our goal is to determine the nature of an event similar to the intense, non-blazar, transient that EGRET has detected near the Galactic plane once in its lifetime. The lack of a radio-loud blazar counterpart and of a spacially coincident X-ray binary indicates either a new manifestation of a non-blazar active galaxy lying behind the Milky Way, capable of producing massive gamma-ray flares, or a new facet of Galactic compact objects. A significant XRT detection of an X-ray counterpart will trigger the proposed 30 ks Chandra observation to locate precisely this counterpart, to constrain the X-ray decay time, and to measure the source spectrum.

R.A.	Dec.	Target Name	Det.	Grating	Exp.Time
		Fermi Transient	ACIS-S	NONE	30

Subject Category: BH AND NS BINARIES

Proposal Number: 12400451

Title: X Per: The Template for the Diffuse Interstellar Medium

PI Name: Lynne Valencic

Galactic interstellar dust is ubiquitous, but many aspects of the grains are not well known. Current model constraints, based on IR-UV data and assumed elemental abundances, are insufficient, as a plethora of viable models exist. Even the abundances are not well known; modelers must use proxies in the absence of direct measurements for the diffuse interstellar medium (ISM). Recent revisions of these proxy values have only added to confusion over which is the best representative for the diffuse ISM, and highlighted the need for direct measurements from the ISM itself. We will measure the O, Mg, Fe, and Si abundances along the X Per sightline with the Chandra LETG/ACIS-S and use them with our multiwavelength data for this sightline to construct a tightly-constrained, realistic grain model.

R.A.	Dec.	Target Name	Det.	Grating	Exp.Time
03:55:23.10	+31:02:45.00	X Per	ACIS-S	LETG	130

Subject Category: BH AND NS BINARIES

Proposal Number: 12400454

Title: Precise Localization of Transient Low-Mass X-ray Binaries

PI Name: Deepto Chakrabarty

We propose to observe up to four neutron star or black hole X-ray transients in outburst to obtain accurate source positions, continuing a successful multi-year multiwavelength program in place since Cycle 6. These positions will allow reobservation of these sources in the X-ray, optical, IR, and radio in order to study their quiescent emission. This program will increase the number of known X-ray transients with good positions, providing a more uniform sample for future work. We will only trigger our program for sources in crowded or highly obscured fields where a position from another instrument (e.g., Swift) is insufficient.

Target Name	Det.	Grating	Exp.Time
X-ray transient	HRC-S	NONE	1
X-ray transient	ACIS-I	NONE	1
X-ray transient	HRC-S	NONE	1
X-ray transient	ACIS-I	NONE	1

Subject Category: BH AND NS BINARIES

Proposal Number: 12400458

Title: INVESTIGATING NEW INTEGRAL SOURCES WITH CHANDRA

PI Name: Adamantia Paizis

We propose to trigger a maximum of 2 Chandra medium (4-12 days) ToO observations on new sources discovered by INTEGRAL. We ask for 20 ksec per observation, using HETGS. The scientific aim is to determine the source position with sub-arcsecond accuracy that only Chandra can provide, enabling multi-wavelength follow-up observations (also coordinated within our team), and to obtain the high resolution HETGS X-Ray spectrum, essential to determine the nature of the new source. With this proposal we aim to continue the successful INTEGRAL-Chandra monitoring program started since Chandra AO 5.

R.A.	Dec.	Target Name	Det.	Grating	Exp.Time
		New INTEGRAL source 1	ACIS-S	HETG	20

Subject Category: BH AND NS BINARIES

Proposal Number: 12400491

Title: Transient LMXBs in Globular Clusters: More Numerous than We Thought?

PI Name: David Pooley

Since the discovery of globular cluster LMXBs in the 1970s, it was assumed that there was only one bright LMXB per cluster. Deep Chandra observations of several globular clusters have revealed that they contain numerous quiescent LMXB systems, any of which could go into outburst. Our observations will determine whether new outbursts from transient LMXBs in NGC 6440, Terzan 5, and Terzan 1 are from the same sources that were previously seen in outburst.

R.A.	Dec.	Target Name	Det.	Grating	Exp.Time
17:48:52.70	-20:21:37.00	NGC 6440	ACIS-S	NONE	2.5
17:48:04.90	-24:46:45.00	Terzan 5	ACIS-S	NONE	10
17:35:47.20	-30:28:54.00	Terzan 1	ACIS-S	NONE	10

Subject Category: BH AND NS BINARIES

Proposal Number: 12400574

Title: Confirmation and Study of a Newly Discovered Nuclear Reaction, Identified in the Neutron Star Crust

PI Name: Robert Rutledge

Spectral observations of transient low mass X-ray binaries, as they descent in intensity into quiescence, have permit unprecedented modeling of the nuclear reactions which take place in the neutron star crust. This modeling has identified anomalous heating hear the top of the neutron star crust, which cannot be explained as due to the simplest prediction of Deep Crustal Heating models; this requires a previously unknown nuclear reaction to explain. We propose to observe the crustal cooling associated with this nuclear reaction. The proposed observations would permit, for the first time, the measurement of reaction parameters for a specific nuclear reaction in the neutron star crust.

R.A.	Dec.	Target Name	Det.	Grating	Exp.Time
19:11:16.00	+00:35:05.80	Aql X-1	ACIS-S	NONE	28

Subject Category: BH AND NS BINARIES

Proposal Number: 12400580

Title: HIGH-RESOLUTION SPECTROSCOPY OF THE PHOTOIONIZED STELLAR WIND OF X-RAY PULSAR OAO 1657

PI Name: Takaaki Tanaka

We propose Chandra HETG observation of X-ray pulsar OAO 1657-415 for 50 ksec exposure time to investigate its peculiar mass accretion onto the neutron star. The binary system is a unique object which shows intermediate features between wind-fed and disk-fed accreting pulsars. It is, therefore, the key target for observational study of accretion onto a highly magnetized star. Recent near-infrared spectroscopy suggested that the donor star of the binary is an Opfe/WNL star and the peculiarity can be explained by the unusual donor type. Our scientific objectives are as follows: 1) explore recombination lines of highly ionized ions in photoionized stellar winds to address the donor fs spectral type, and 2) constrain matter distribution in the system by using iron fluorescent line complex.

R.A.	Dec.	Target Name	Det.	Grating	Exp.Time
17:00:48.90	-41:39:21.60	OAO 1657-415	ACIS-S	HETG	50

Subject Category: BH AND NS BINARIES

Proposal Number: 12400656

Title: The Unusual X-ray Binaries of the Globular Cluster NGC 6652

PI Name: Craig Heinke

We request a 50 ksec study of 3 highly unusual X-ray binaries in the dense globular cluster NGC 6652, which contains a bright LMXB. Source B, observed at Lx~10^{34} ergs/s, may be a bright LMXB seen edge-on, or an X-ray binary in an unusual accretion state. Source C appears to be a luminous CV, with strong blackbody-like emission below 0.6 keV; is it an X-ray luminous polar CV? Source D shows a puzzling soft spectrum, with a suggestion of a strong emission line at 1 keV; an old nova shell? We will survey faint X-ray sources down to Lx=10^31 ergs/s, determining if the X-ray source excess continues to fainter luminosities and constraining models of X-ray binary production. We request 3 orbits of deep, dithered WFC3 HST time to identify faint blue cataclysmic variables.

R.A.	Dec.	Target Name	Det.	Grating	Exp.Time
18:35:45.70	-32:59:25.00	NGC 6652	ACIS-S	NONE	50

Subject Category: BH AND NS BINARIES

Proposal Number: 12400666

Title: A Long Multiwavelength Study of GRS 1915+105: Accretion/Ejection Physics of the Disk Wind and Radio Jet

PI Name: Joseph Neilsen

We propose a 120 ks HETGS/CC-mode observation of GRS 1915+105 for targeted studies of strong X-ray variability. In such a state, where myriad absorption lines from a highly ionized accretion disk wind abound, our long look will reveal the missing link between this hot wind, the bizarre X-ray variability, and state changes in the accretion disk. To complement our high-resolution X-ray study, we propose joint radio/infrared monitoring with the EVLA and NIRI on Gemini North, two of the world's premier radio and infrared facilities, in order to make the first-ever direct measurement of the wind-jet interaction on timescales possibly as short as 10 seconds. This will be one of the most sensitive and highest-resolution multiwavelength campaigns on this enigmatic black hole to date.

R.A.	Dec.	Target Name	Det.	Grating	Exp.Time
19:15:11.60	+10:56:44.10	GRS 1915+105	ACIS-S	HETG	120

Subject Category: BH AND NS BINARIES

Proposal Number: 12400717

Title: X-ray observations of a nearby, old Rotating Radio Transient

PI Name: Maura McLaughlin

RRAT J1840-14 is characterized by frequent radio bursts and has a distance of only 850 pc. With a spin period of 6.6 s and a characteristic age of 17 Myr, it is in the pulsar death valley where radio emission is thought to fail. The inferred population of RRATs is large and requires a link between neutron star classes to avoid a discrepancy with the supernova rate. Therefore RRATs may be transition objects linking the normal radio pulsars, magnetars, the INS, and "dead" pulsars, although the direction of this evolution is unknown. These observations will determine how J1840-14 is related to the radio pulsar and INS classes. It is unique as a strong, nearby source in this crucial region of P-Pdot space and will be the second oldest neutron star detected at X-ray energies.

R.A.	Dec.	Target Name	Det.	Grating	Exp.Time
18:40:32.00	-14:19:02.00	J1840-14	ACIS-S	NONE	30

Subject Category: BH AND NS BINARIES

Proposal Number: 12400736

Title: Constraining the X-ray spectrum of a nearby unusual binary pulsar

PI Name: Duncan Lorimer

We propose a 30 ks ACIS-S observation of newly discovered binary pulsar J2222-0137. With a spin period of 32 ms and minimum companion mass of 1.1 solar masses, this pulsar seems to be a member of the rare class of intermediate mass binary pulsars. With an inferred distance of only 300 pc, this is the second closest pulsar binary system (after J0437-4715) and an excellent target for high precision spectral measurements, a neutron star radius measurement, a search for extended emission, and a possible constraint on the nature of this unusual pulsar's companion.

R.A.	Dec.	Target Name	Det.	Grating	Exp.Time
22:22:05.90	-01:37:15.50	J2222-0137	ACIS-S	LETG	30

Subject Category: BH AND NS BINARIES

Proposal Number: 12400740

Title: First X-ray Observations of Four New Fermi-Associated Black-Widow Pulsars

PI Name: Maura McLaughlin

We request 70 ks for ASIS-S observations of four new binary pulsars, all associated with unidentified Fermi sources. Three of these pulsars are classical "black widow" pulsars, with short orbital periods, prolonged radio eclipses, and low companion masses. The fourth shows prolonged eclipses and a short orbital period but has a larger companion mass. It may be a black widow in the earliest stages of companion ablation or a newly recycled pulsar. These observations will cover one full orbit for all four pulsars and will allow constraints on spectra, orbital variability, and the existence of any extended emission. Only two Galactic black widow pulsars have ever been observed at X-ray energies; the proposed observations will dramatically improve our knowledge of this class of objects.

R.A.	Dec.	Target Name	Det.	Grating	Exp.Time
00:23:18.00	+09:22:30.00	J0023+09	ACIS-S	NONE	13
18:10:35.00	+17:44:30.00	J1810+17	ACIS-S	NONE	20
22:15:54.00	+51:36:37.00	J2215+41	ACIS-S	NONE	17
22:56:56.00	-10:24:34.00	J2256-10	ACIS-S	NONE	20

Subject Category: BH AND NS BINARIES

Proposal Number: 12400752

Title: Spectral state dependence of the extended accretion flow components in LMXBs

PI Name: Jeroen Homan

LMXBs that are seen nearly edge-on offer a unique view of the extended components of accretion flows, such as disk outflows, warm absorbers, and accretion disk coronae. Our view of how the properties of these components change as a function of X-ray spectral state is still fairly limited. A chance to increase our understanding of this aspect of LMXB accretion flows is offered by XTE J1710-281, a poorly studied dipping/eclipsing neutron star LMXB that, unlike similar sources, shows frequent spectral state transitions. We propose two 75 ks Chandra/HETGS observations of XTE J1701-281, spaced by approximately 2 weeks. Our aim is to observe the source in different spectral states, and study the changes in the accretion disk corona and warm absorber components that we expect to detect.

R.A.	Dec.	Target Name	Det.	Grating	Exp.Time
17:10:12.60	-28:07:50.90	XTE J1710-281	ACIS-S	HETG	150

Subject Category: BH AND NS BINARIES

Proposal Number: 12400796

Title: Validating Neutron Star Radius Measurements

PI Name: Deepto Chakrabarty

Spectral analysis of transient neutron star X-ray emission during bursts and quiescence were both used to estimate the NS radii for different sources. The validities of these methods need to be verified by performing them on the same source respectively. Transient type-I (thermonuclear) X-ray bursters are excellent candidates for testing the consistency between these methods, since they were detected in both bursts and quiescence. Out of 3 candidates: Cen X-4, Aql X-1 and 4U 1608-52, 4U 1608-52 turns out to be the best one due to the lack of archival RXTE burst data for Cen X-4 and the previous reported significant luminosity and temperature variability for Aql X-1 in quiescence. Therefore, we propose a 25 ks Chandra/ACIS-S observation of 4U 1608-52.

R.A.	Dec.	Target Name	Det.	Grating	Exp.Time
16:12:43.00	-52:25:23.00	4U 1608-522	ACIS-S	NONE	25

Subject Category: BH AND NS BINARIES

Proposal Number: 12400823

Title: The Quiescent X-Ray Luminosity of Stellar Mass Black Holes

PI Name: Mark Reynolds

The defining property of a black hole is its event horizon. Previous Chandra observations have revealed the quiescent X-ray luminosity of the Galactic stellar mass black holes to be systematically less luminous (by factors of ~ 100) than neutron star binaries at similar orbital periods. This has been interpreted as evidence for the existence of the black hole event horizon, as opposed to the solid surface present in neutron stars. Currently such observations are the only means by which the presence or not of the event horizon may be inferred. Here, we propose to use Chandra to constrain the X-ray luminosity of the quiescent Galactic stellar mass black hole GS 1354-64.

R.A.	Dec.	Target Name	Det.	Grating	Exp.Time
13:58:09.70	-64:44:05.20	GS 1354-64	ACIS-S	NONE	40

Subject Category: BH AND NS BINARIES

Proposal Number: 12400833

Title: Filling the gap in understanding the wind structure of HDE 226868 / Cyg X-1

PI Name: Manfred Hanke

We propose to observe the BH HMXB system HDE 226868 / Cyg X-1 with Chandra-HETGS for 24 ks (corresponding to Delta phi=0.05 in orbital phase) between orbital phases phi=0.25 and phi=0.4 -- an interval not covered by previous Chandra observations. The spectroscopic analysis of the highly photoionized wind during this phase will improve our understanding of the wind in general and its implications for the accretion flow onto the black hole, and also of the conditions necessary for the formation of a narrow Fe K flourescence line. In addition, cessation of dipping is expected during this phase. If seen, the morphology and spectral signatures of the last dips will constrain the location and kinematics of the structures in the O-star wind causing these absorption events.

R.A.	Dec.	Target Name	Det.	Grating	Exp.Time
19:58:21.70	+35:12:05.80	Cyg X-1	ACIS-S	HETG	24

Subject Category: BH AND NS BINARIES

Proposal Number: 12400837

Title: Identifying the Optical Counterparts of ULXs in the Blue Compact Dwarf Galaxy NGC 4861 (Mrk 59)

PI Name: Yi-Jung Yang

We propose to observe two ultraluminous X-ray sources (ULXs) in the metal-deficit blue compact dwarf (BCD) galaxy NGC 4861 (Mrk 59) with Chandra. From previous XMM-Newton observations, we obtained luminosities of Lx~ 1.1x10^40 erg/s for the brightest source (ULX-1) and Lx ~ 4.9x10^39 erg/s for the second brightest source (ULX-2) in the field of view. From H-alpha and [S II] images, we find that both sources are in the proximity of regions of diffuse nebulosity, which may be powered by the ULXs. In order to precisely locate the ULXs, we propose to perform a 20 ks Chandra ACIS-I observation. This will allow us to perform very precise astrometry and locate the sources with very high accuracy.

R.A.	Dec.	Target Name	Det.	Grating	Exp.Time
12:58:59.60	+34:54:26.30	NGC 4861	ACIS-I	NONE	20

Subject Category: BH AND NS BINARIES

Proposal Number: 12400869

Title: Exposing the symbiosis of 3A 1954+319

PI Name: Katja Pottschmidt

We propose a 40 ksec observation of 3A 1954+319, the first long Chandra observation of this Symbiotic X-ray Binary (SyXB) consisting of a neutron star and an M-star giant companion. Our aim is to conduct the first study of the soft X-ray spectrum with CCD resolution and thereby widen the knowledge about this source class, which to date has only 8 members. The source shows one of the longest known spin periods, ~19 ksec, thus -- depending on observation gaps -- up to two full pulses could be covered. The main aims of the observation are to determine the parameters of the M-star wind and of the accretion region and to investigate the torque transfer from the wind to the neutron star.

R.A.	Dec.	Target Name	Det.	Grating	Exp.Time
19:55:42.30	+32:05:49.20	3A 1954+319	ACIS-S	HETG	40

Subject Category: BH AND NS BINARIES

Proposal Number: 12400885

Title: The Nearest and Brightest Quiescent Low Mass X-ray Binaries

PI Name: Robert Rutledge

We propose to observe 22 RASS/BSC X-ray sources, using a selection technique optimized to discover qLMXBs among them. We expect 11 true associations with proposed IR counterparts; while the number of qLMXBs we will discover using this approach is highly uncertain, even one identified would be the first NS qLMXB discovered in the field without an historical outburst, which would change the means by which we study and learn about the population of transient neutron star low mass X-ray binaries.

R.A.	Dec.	Target Name	Det.	Grating	Exp.Time
13:47:51.30	+28:36:39.00	1RXS J134751.3+283639	ACIS-S	NONE	1.8
14:47:01.10	+11:45:36.00	1RXS J144701.1+114536	ACIS-S	NONE	1
10:19:52.40	-14:07:27.00	1RXS J101952.4-140727	ACIS-S	NONE	1
01:19:55.70	-20:10:25.00	1RXS J011955.7-201025	ACIS-S	NONE	1.6
06:48:55.30	-25:23:50.00	1RXS J064855.3-252350	ACIS-S	NONE	1
18:47:56.10	-22:19:38.00	1RXS J184756.1-221938	ACIS-S	NONE	1
14:03:37.50	+39:36:27.00	1RXS J140337.5+393627	ACIS-S	NONE	1.8
05:47:47.20	-19:56:09.00	1RXS J054747.2-195609	ACIS-S	NONE	1
13:56:06.80	+41:36:13.00	1RXS J135606.8+413613	ACIS-S	NONE	2
12:59:48.70	+34:23:25.00	1RXS J125948.7+342325	ACIS-S	NONE	3.2
13:21:38.70	+51:17:45.00	1RXS J132138.7+511745	ACIS-S	NONE	3.2
11:56:06.70	+05:14:14.00	1RXS J115606.7+051414	ACIS-S	NONE	2.7
03:41:21.40	-46:30:59.00	1RXS J034121.4-463059	ACIS-S	NONE	1.6
21:27:43.50	-22:11:45.00	1RXS J212743.5-221145	ACIS-S	NONE	1
22:10:30.30	-30:05:46.00	1RXS J221030.3-300546	ACIS-S	NONE	1.5
14:31:57.40	+37:06:35.00	1RXS J143157.4+370635	ACIS-S	NONE	1.1
10:02:27.00	-71:04:44.00	1RXS J100227.0-710444	ACIS-S	NONE	3.2
04:45:49.60	-57:26:18.00	1RXS J044549.6-572618	ACIS-S	NONE	2.3
08:19:52.40	-13:19:24.00	1RXS J081952.4-131924	ACIS-S	NONE	1.6
02:12:46.20	-34:22:56.00	1RXS J021246.2-342256	ACIS-S	NONE	2.3
04:27:04.50	-59:48:54.00	1RXS J042704.5-594854	ACIS-S	NONE	3.2
09:57:03.20	+56:31:38.00	1RXS J095703.2+563138	ACIS-S	NONE	2.7

Subject Category: BH AND NS BINARIES

Proposal Number: 12400892

Title: PRECISE CHANDRA LOCALIZATION OF FAINT PERSISTENT X-RAY SOURCES NEAR THE GALACTIC PLANE

PI Name: Alexander Lutovinov

For this purpose we used deep observations of the Galactic plane, performed by the INTEGRAL observatory over 2003-2009. In our project we propose to perform snapshot observations of a remaining sample of INTEGRAL sources -- HMXB candidates -- in order to fill the gap in identification completeness. CHANDRA observations will give us astrometric positions of sources which will allow us to identify their optical counterparts, and therefore the nature of the binary. Their subsequent studies in optical or NIR spectral bands are impossible without knowledge about accurate astrometric positions.

R.A.	Dec.	Target Name	Det.	Grating	Exp.Time
17:42:40.80	-30:22:37.20	IGR J17427-3018	HRC-I	NONE	1.5
18:29:19.90	-12:12:46.80	IGR J18293-1213	HRC-I	NONE	1
18:22:00.00	-13:47:24.00	IGR J18219-1347	HRC-I	NONE	1
19:01:40.30	+01:26:24.00	XTE J1901+014	HRC-I	NONE	1
12:13:29.80	-60:15:54.00	IGR J12134-6015	HRC-I	NONE	1

Subject Category: BH AND NS BINARIES

Proposal Number: 12400915

Title: Refining the positions of soft gamma-ray sources with Chandra

PI Name: Arash Bodaghee

We propose to observe 5 soft gamma-ray sources (IGRs) with Chandra. Their X-ray error circles encompass several potential optical/infrared counterparts leading to ambiguity in the source classification. Therefore, we require the fine spatial resolution of Chandra in order to minimize the size of the error circle. Since we are only interested in the X-ray positions, we ask for short 1-ks observations with the HRC-I allowing us to obtain positions with sub-arcsecond accuracy. These refined positions will then allow us to eliminate all but a single counterpart for follow-up observations in the optical and infrared bands, which will enable us to finally provide firm classifications for these systems.

R.A.	Dec.	Target Name	Det.	Grating	Exp.Time
14:04:17.40	-61:49:12.00	IGR J14043-6148	HRC-I	NONE	1
16:35:53.80	-47:25:41.10	IGR J16358-4726	HRC-I	NONE	1
16:19:05.40	-46:42:12.00	IGR J16393-4643	HRC-I	NONE	1
17:09:07.60	-36:24:24.90	IGR J17091-3624	HRC-I	NONE	1
17:59:45.70	-22:01:39.00	IGR J17597-2201	HRC-I	NONE	1

Subject Category: BH AND NS BINARIES

Proposal Number: 12400926

Title: Census of the Normal Spiral Arm Region

PI Name: John Tomsick

Despite having only moderate hard X-ray sensitivity, the INTErnational Gamma-Ray Astrophysics Laboratory (INTEGRAL) has greatly expanded our knowledge of High-Mass X-ray Binaries (HMXBs) by finding large numbers and new types of HMXBs. There are good reasons to think that even fainter HMXBs should be present, and we propose to use Chandra to survey part of the Norma region, which is the location with the highest density of HMXBs. This will be important for understanding the HMXB population and its evolution, the HMXB luminosity function and how faint wind-accrting HMXBs can be, as well as providing critical estimates for Advanced-LIGO source rates. IR follow-up is proposed, and the subarcsecond Chandra positions are critical.

R.A.	Dec.	Target Name	Det.	Grating	Exp.Time
16:37:27.30	-47:07:36.80	Norma Region	ACIS-I	NONE	540

Subject Category: BH AND NS BINARIES

Proposal Number: 12400936

Title: Searching New Millisecond Pulsar Fields for X-ray Counterparts

PI Name: Michael Wolff

We propose to make ACIS observations of a selected set of newly discovered radio millisecond pulsars found in searches targeting Fermi LAT unidentified sources. The goal is to detect and do a preliminary characterization of the X-ray counterpart for each pulsar, none of which have been the subject of deep X-ray observations thus far. This study will significantly increase the number of X-ray detected millisecond pulsars and shed light on the X-ray characteristics of the MSP population. In addition, it will identify promising sources for deeper observations that will probe the X-ray emission mechanisms of MSPs and constrain the equation of state of matter at super-nuclear densities.

R.A.	Dec.	Target Name	Det.	Grating	Exp.Time
15:14:05.90	-49:45:41.00	PSRJ1514-49	ACIS-S	NONE	10
16:58:39.50	-53:20:15.40	PSRJ1658-53	ACIS-S	NONE	10
13:02:27.20	-32:55:29.30	PSRJ1302-32	ACIS-S	NONE	10
20:17:18.70	+06:02:53.20	PSRJ2017+06	ACIS-S	NONE	10
11:03:59.20	-53:55:45.10	PSRJ1103-53	ACIS-S	NONE	10

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