Accepted Cycle 15 Observing Proposals

CLUSTERS OF GALAXIES

Proposal Number	Subject Category	PI Name	Type	Time (ks)	Title
15800006	CLUSTERS OF GALAXIES	Sun	GO	48	RXJ1324.7-5736: one of the closest and brightest cool core clusters
15800201	CLUSTERS OF GALAXIES	Romani	GO	100	Imaging spectroscopy of the Remarkable Halo of 4C+37.11
15800314	CLUSTERS OF GALAXIES	Buote	GO	100	The Massive Fossil Cluster RXJ1416.4+2315
15800323	CLUSTERS OF GALAXIES	Gastaldello	GO	51	Probing with X-ray the mass distribution in the lensing cluster A1703
15800332	CLUSTERS OF GALAXIES	Pacaud	GO	205	SNAPSHOTS IN THE HISTORY OF DISSOCIATIVE MAJOR MERGERS
15800369	CLUSTERS OF GALAXIES	RUDNICK	GO	180	Abell 2256: New paradigms for thermal/relativistic interactions?
15800442	CLUSTERS OF GALAXIES	Hardcastle	GO	180	Powerful radio galaxies in rich clusters
15800474	CLUSTERS OF GALAXIES	Sanders	LP	500	Deep imaging and spectroscopy of the Centaurus cluster: metals and filaments
15800532	CLUSTERS OF GALAXIES	Lovisari	GO	40	TO THE VIRIAL RADIUS OF THE MOST LUMINOUS LOCAL GALAXY GROUP: UGC03957
15800543	CLUSTERS OF GALAXIES	McDonald	GO	59.1	Searching for Signatures of Episodic AGN Feedback in the Core of the Phoenix Cluster
15800582	CLUSTERS OF GALAXIES	Sarazin	GO	120	Did Precessing Jets and/or a Merger Make a Diamond in Abell 2626?
15800614	CLUSTERS OF GALAXIES	Donahue	GO	90	Unmasking Galaxy Clusters Masquerading As Quasars
15800657	CLUSTERS OF GALAXIES	Hughes	LP	498	Chandra Observations of a Complete Sample of SZE Clusters from ACT
15800664	CLUSTERS OF GALAXIES	Allen	GO	250	A deep study of ram-pressure stripping, metal ridges, and AGN feedback in the Ophiuchus Cluster
15800706	CLUSTERS OF GALAXIES	Kraft	LP	500	Hydrodynamics of merging and stripping in the Fornax Cluster: A Deep Chandra observation of NGC 1404
15800803	CLUSTERS OF GALAXIES	Mantz	GO	65	Setting the Scale: Supporting precision cluster cosmology with Chandra observations of low-z lensing clusters
15800858	CLUSTERS OF GALAXIES	Jones	LP	520	Clusters, Galaxies, and AGN in HST Frontier Fields

Subject Category: CLUSTERS OF GALAXIES

Proposal Number: 15800006

Title: RXJ1324.7-5736: one of the closest and brightest cool core clusters

Type: GO Total Time (ks): 48

PI Name: Ming Sun

Discovery of X-ray cavities and shocks related to the outbursts of the central AGN has been one of Chandra's legacies. These features serve as calorimeters for the total energy outputs of the AGN, allowing important constraints on the evolution of SMBHs. Chandra is ideal for X-ray bright cool cores, especially nearby ones hosting strong radio AGN. While it is natural to believe that all the X-ray brightest, nearby cool cores have been observed by Chandra at this stage, we found that one of the brightest cool core clusters, in fact the 6th brightest one in terms of the intrinsic flux, has not been observed by Chandra. It also hosts a strong central radio AGN. We request a 48 ks observation for this interesting system to search for substructures related to AGN heating.

R.A.	Dec.	Target Name	Det.	Grating	Exp.Time (ks)
13:24:46.50	-57:36:31.80	RXJ1324.7-5736	ACIS-S	NONE	48

Subject Category: CLUSTERS OF GALAXIES

Proposal Number: 15800201

Title: Imaging spectroscopy of the Remarkable Halo of 4C+37.11

Type: GO Total Time (ks): 100

PI Name: Roger Romani

4C+37.11 is a unique source with two active nuclei (resolved by VLBI at 7pc separation) in a luminous elliptical surrounded by a bright X-ray halo; this is a likely fossil cluster. We see remarkable X-ray structure: arcsecond-scale cavities apparently associated with the AGN outflows and arcmin-scale features in the X-ray halo that may be cold fronts or shocks associated with recent merger activity. We propose an ACIS exposure that will allow a spectroscopic study of these features and a characterization of the temperature, density, pressure and entropy profiles of the intergalactic medium surrounding the bright central galaxy. These data will give important insight into the history of this as yet unmerged SuperMassive Binary Black Hole and its feedback on the X-ray halo.

R.A.	Dec.	Target Name	Det.	Grating	Exp.Time (ks)
04:05:49.20	+38:03:32.00	4C+37.11	ACIS-I	NONE	100

Subject Category: CLUSTERS OF GALAXIES

Proposal Number: 15800314

Title: The Massive Fossil Cluster RXJ1416.4+2315

Type: GO Total Time (ks): 100

PI Name: David Buote

Our preliminary analysis of AO7 Suzaku data and a shallow Chandra observation of the fossil cluster RXJ 1416.4+2315 does not find evidence for the gas clumping invoked to explain the flat entropy profiles found near r_vir in several nearby clusters. Instead its ICM properties at r_vir are consistent with adiabatic cluster formation as we found previously for the fossil group/cluster RXJ 1159+5531, which may reflect that hydrostatic equilibrium is very accurate in these highly evolved fossil systems. We propose (1) snapshot offset Chandra ACIS-I observations to resolve the brightest discrete sources to better characterize the CXB, and (2) a deeper Chandra central pointing to provide key leverage at smaller radii to better constrain the mass, baryon, and entropy profiles interior to r_vir.

R.A.	Dec.	Target Name	Det.	Grating	Exp.Time (ks)
14:16:21.60	+23:05:25.90	RXJ1416.4+2315 Offset 2	ACIS-I	NONE	5
14:16:37.00	+23:25:22.10	RXJ1416.4+2315 Offset 3	ACIS-I	NONE	5
14:15:50.90	+23:21:48.70	RXJ1416.4+2315 Offset 4	ACIS-I	NONE	5
14:16:26.00	+23:15:23.00	RXJ1416.4+2315 Center	ACIS-I	NONE	80
14:15:47.00	+23:10:38.80	RXJ1416.4+2315 Offset 1	ACIS-I	NONE	5

Subject Category: CLUSTERS OF GALAXIES

Proposal Number: 15800323

Title: Probing with X-ray the mass distribution in the lensing cluster A1703

Type: GO Total Time (ks): 51

PI Name: Fabio Gastaldello

We propose a 51 ks observation of the lensing, X-ray luminous cluster A1703 to constrain its total and hot gas mass profile. A1703 is an exceptional target from the strong lensing point of view because there are multiple strong lens systems for a wide range of source redshifts constraining the enclosing mass at different radii. It is also unusually relaxed providing a special opportunity to study its mass profile by applying hydrostatic equilibrium. Given the still debated issue of very high concentrations found for some massive lensing clusters, by obtaining high quality X-ray data for a well relaxed cluster we will perform a key test for the Lambda CDM structure formation scenario.

R.A.	Dec.	Target Name	Det.	Grating	Exp.Time (ks)
13:15:00.70	+51:49:10.00	Abell 1703	ACIS-I	NONE	51

Subject Category: CLUSTERS OF GALAXIES

Proposal Number: 15800332

Title: SNAPSHOTS IN THE HISTORY OF DISSOCIATIVE MAJOR MERGERS

Type: GO Total Time (ks): 205

PI Name: Florian Pacaud

We propose joint Chandra/HST observations of two z=0.3 cluster mergers presenting offsets between the gas and dark matter distribution. Both were discovered within the follow-up program of the APEX-SZ experiment. The first one shows a bullet structure with a probable bow shock. The new data will permit an accurate joint X-ray, Sunyaev-Zel'dovich effect and lensing analysis to characterize both the thermodynamical state of its intracluster gas and the distribution of dark matter around it. The second cluster lacks good X-ray data and we request a short Chandra observations to confirm the gas distribution. Combined with three similar systems from the APEX-SZ sample, we aim at reconstructing obsevationally the time sequence of dissociative mergers.

R.A.	Dec.	Target Name	Det.	Grating	Exp.Time (ks)
02:45:27.70	-53:02:10.00	Abell S0295	ACIS-I	NONE	180
11:35:36.80	-20:19:42.00	RXC J1135.6-2019	ACIS-I	NONE	25

Subject Category: CLUSTERS OF GALAXIES

Proposal Number: 15800369

Title: Abell 2256: New paradigms for thermal/relativistic interactions?

Type: GO Total Time (ks): 180

PI Name: LAWRENCE RUDNICK

The classic picture of merger-driven shocks creating cluster peripheral radio re lics is in trouble. Abell 2256 presents unique challenges to shock-driven models, exacerbating issues in the recent literature. It also provides the only opportunity to probe instabilities in the shock plane, because of the orientation of its spectacular filamentary relic. We have identified a possible thermal shock associated with the relic, but the canonical bright radio edge is missing. We have also found a unique structure where a tailed radio galaxy has apparently punched through a cold front. For a variety of fundamental cluster physics questions related to the interaction of thermal and relativistic plasmas, Abell 2256, with this proposed set of deep Chandra observations, alone holds the key.

R.A.	Dec.	Target Name	Det.	Grating	Exp.Time (ks)
17:02:42.50	+78:42:03.70	Abell 2256	ACIS-I	NONE	180

Subject Category: CLUSTERS OF GALAXIES

Proposal Number: 15800442

Title: Powerful radio galaxies in rich clusters

Type: GO Total Time (ks): 180

PI Name: Martin Hardcastle

High-power, `classical double' radio galaxies in cluster environments are rare at low z and so poorly studied, but they are of interest because their dynamics are relatively well understood and can be modeled in detail; they may provide significant energy/entropy input to clusters over the lifetime of the Universe. We have selected two bright clusters from a snapshot survey of the low-redshift 3C radio galaxies; both show evidence for strong RG/cluster interactions. We propose to observe these for long enough to test shock models (including the results of numerical modeling) and establish the energetic input to the cluster by the radio galaxies. Combined with existing data, this will give us the basis of a relationship between radio power and cluster energy input via shocks.

R.A.	Dec.	Target Name	Det.	Grating	Exp.Time (ks)
15:31:25.40	+35:33:40.20	3C320	ACIS-S	NONE	110

Subject Category: CLUSTERS OF GALAXIES

Proposal Number: 15800474

Title: Deep imaging and spectroscopy of the Centaurus cluster: metals and filaments

Type: LP Total Time (ks): 500

PI Name: Jeremy Sanders

The Centaurus cluster is nearby, bright and has a metallicity three times that of other nearby clusters. It is one of the best targets in which to study ICM metal physics. We will probe metallicity structure to sub-kpc scales, matching AGN feedback scales. The central drop in metallicity implies metals are locked in dust associated with filaments. We will examine Ar/Ne which are not, testing this hypothesis. The spectrum of metallicity fluctuations will probe diffusion and turbulence. Additional science goals will be to examine Type Ia/II enrichement, the pressure variations caused by radio bubbles to study feedback, the magnetic field structure and the soft X-ray connection to the optical filaments.

R.A.	Dec.	Target Name	Det.	Grating	Exp.Time (ks)
12:48:48.90	-41:18:43.80	Centaurus cluster	ACIS-S	NONE	500

Subject Category: CLUSTERS OF GALAXIES

Proposal Number: 15800532

Title: TO THE VIRIAL RADIUS OF THE MOST LUMINOUS LOCAL GALAXY GROUP: UGC03957

Type: GO Total Time (ks): 40

PI Name: Lorenzo Lovisari

Detailed and extended measurements out to large radii have the potential of improving our understanding of the cluster growth, structure, mass and metal enrichment of massive bound systems. While the physical properties of the outskirts of massive clusters have been already obtained for a handful of objects, the region near the virial radius remain relatively unexplored in case of galaxy groups. We propose 4 Chandra snapshots to detect all the bright point sources in the outskirt of the most luminous local galaxy group UGC 03957 to obtain a careful estimation of the cosmic X-ray background component and determine the physical properties (temperature, metallicity and mass profiles) with our 270 ksec Suzaku observations, limited only by the statistical uncertainty.

R.A.	Dec.	Target Name	Det.	Grating	Exp.Time (ks)
07:39:42.30	+55:48:46.80	UGC 03957 NORTH	ACIS-I	NONE	10
07:43:53.40	+55:30:33.80	UGC 03957 EAST	ACIS-I	NONE	10
07:42:05.80	+55:02:42.70	UGC 03957 SOUTH	ACIS-I	NONE	10
07:38:14.40	+55:15:17.60	UGC 03957 WEST	ACIS-I	NONE	10

Subject Category: CLUSTERS OF GALAXIES

Proposal Number: 15800543

Title: Searching for Signatures of Episodic AGN Feedback in the Core of the Phoenix Cluster

Type: GO Total Time (ks): 59.1

PI Name: Michael McDonald

In the core of the Phoenix cluster (SPT-CLJ2344-4243) is the strongest cooling flow on record, with a classical cooling rate of ~2700 Msun/yr. In contrast to low redshift "cool core clusters", which are converting only ~5% of the predicted cooling into stars, this cluster is experiencing an 800 Msun/yr starburst in the central, most-massive galaxy, corresponding to ~30% of the predicted cooling flow. This unique system begs the question: Why isn't AGN feedback preventing star formation? In order to address this outstanding question, we propose a combined GO+GTO program to search for cavities/bubbles in a deep X-ray image of the Phoenix cluster, allowing us to quantify the balance, or lack thereof, between cooling and feedback, providing a potential explanation for this exotic system.

R.A.	Dec.	Target Name	Det.	Grating	Exp.Time (ks)
23:44:42.00	-42:42:52.60	SPT-CLJ2344-4243	ACIS-I	NONE	59.1

Subject Category: CLUSTERS OF GALAXIES

Proposal Number: 15800582

Title: Did Precessing Jets and/or a Merger Make a Diamond in Abell 2626?

Type: GO Total Time (ks): 120

PI Name: Craig Sarazin

The cool core cluster A2626 has an amazing radio source. The cD IC5338 has 2 nuclei 3" apart. Radio/X-ray jets from the SW nucleus lead to 2 narrow N and S radio arcs; these fit the working surfaces of a pair of precessing jets. Recent radio data also show a W arc, and an E edge. We suggest these are due to another pair of precessing jets from the NE nucleus. The S0 galaxy IC5337 is merging from the west; the W arc might also be a radio relic due to a merger shock. Our proposed observation will search for a second pair of precessing jets, an X-ray AGN in the NE nucleus, and the interaction of the jets and arcs with the X-ray gas. We will detect a merger shock associated with the W arc and S0 galaxy, if present. A2626 provides a unique test of precessing jets and merging SMBHs.

R.A.	Dec.	Target Name	Det.	Grating	Exp.Time (ks)
23:36:30.50	+21:08:45.50	Abell 2626	ACIS-S	NONE	120

Subject Category: CLUSTERS OF GALAXIES

Proposal Number: 15800614

Title: Unmasking Galaxy Clusters Masquerading As Quasars

Type: GO Total Time (ks): 90

PI Name: Megan Donahue

We propose to observe 5 of 25 galaxy clusters associated with RASS Bright Sources. None of these clusters, selected from the SDSS GMBCG catalog of 55,000 clusters, were previously known to be X-ray luminous clusters. These clusters may be missed by X-ray cluster surveys, as the Phoenix Cluster was, because of their association with bright ROSAT point sources. Understanding objects like these and their underrepresentation in previous X-ray cluster surveys is important for precision cluster cosmology, for accurately measuring the evolution of cool cluster cores, and for understanding the connection between X-ray bright AGNs in brightest cluster galaxies and the ICM. We will address these issues by separating the AGN and extended X-ray contributions in these sources.

R.A.	Dec.	Target Name	Det.	Grating	Exp.Time (ks)
10:30:35.20	+51:32:32.10	RXJ103035.2+513229	ACIS-I	NONE	20
08:54:50.60	+62:18:50.00	RXJ085451.0+621843	ACIS-I	NONE	18
11:19:08.90	+09:00:22.80	RXJ111908.5+090017	ACIS-I	NONE	22
14:56:10.90	+30:21:06.30	RXJ145611.1+302108	ACIS-I	NONE	20
09:05:33.50	+18:40:02.60	RXJ090533.4+184011	ACIS-I	NONE	10

Subject Category: CLUSTERS OF GALAXIES

Proposal Number: 15800657

Title: Chandra Observations of a Complete Sample of SZE Clusters from ACT

Type: LP Total Time (ks): 498

PI Name: John Hughes

We propose to continue our program with Chandra to observe a complete sample of galaxy clusters detected by the Atacama Cosmology Telescope using the Sunyaev-Zeldovich effect (SZE). The proposed ACIS-I observations of 10 massive, newly-discovered SZE clusters will provide a precision calibration of the SZE signal versus mass scaling law out to redshifts of 1. This effort is part of an intensive multi-wavelength campaign to produce an unbiased, well-observed sample of massive galaxy clusters out to high redshifts for cosmological investigations.

R.A.	Dec.	Target Name	Det.	Grating	Exp.Time (ks)
00:22:13.00	-00:36:33.80	ACT-CL J0022-0036	ACIS-I	NONE	72
00:59:08.50	-00:50:05.80	ACT-CL_J0059-0049	ACIS-I	NONE	40
00:14:54.10	-00:57:08.50	ACT-CL_J0014-0056	ACIS-I	NONE	30
02:06:13.40	-01:14:17.00	ACT-CL_J0206-0114	ACIS-I	NONE	30
21:54:32.40	-00:49:00.40	ACT-CL_J2154-0049	ACIS-I	NONE	65

Subject Category: CLUSTERS OF GALAXIES

Proposal Number: 15800664

Title: A deep study of ram-pressure stripping, metal ridges, and AGN feedback in the Ophiuchus Cluster

Type: GO Total Time (ks): 250

PI Name: Steven Allen

We propose a 250 ks ACIS-I observation of the inner regions of the Ophiuchus Cluster. The existing 50 ks Chandra observation has already provided remarkable insights into the effects of ram pressure on a cool core in motion within a rich cluster. Using a combination of new X-ray and radio data, we will explore this system in unprecedented detail, studying the thermodynamics and multiphase structure within the surviving cool core. At the outer boundary of the core, we will search for the development of shearing instabilities and the onset of mixing. Beyond the core, we will study the large, coherent ridges of enhanced metallicity, their origins, and relation to past activity of the central AGN. At yet larger radii, we will probe in detail for the first time the structure of the ambient ICM.

R.A.	Dec.	Target Name	Det.	Grating	Exp.Time (ks)
17:12:27.70	-23:22:07.00	Ophiuchus Cluster	ACIS-I	NONE	250

Subject Category: CLUSTERS OF GALAXIES

Proposal Number: 15800706

Title: Hydrodynamics of merging and stripping in the Fornax Cluster: A Deep Chandra observation of NGC 1404

Type: LP Total Time (ks): 500

PI Name: Ralph Kraft

Early-type galaxies falling into clusters provide an excellent probe for ICM properties as they are stripped due to their motion through the cluster gas. They form a tail of gas attached to the remnant merger core (RMC). Both the upstream and side edge of the RMC and the tail are sites where the cool galaxy gas and the hot ambient ICM could mix, unless prevented by ICM viscosity or magnetic fields. The RMC of NGC 1404 in the Fornax cluster is the best target to observe the absence or presence of this mixing. We propose 500 ks Chandra/ACIS-S observations of NGC 1404 to make a direct measurement of gas mixing and viscosity in the ICM with a sensitivity that cannot be reached in any other target. We support the interpretation of our data by specifically tailored hydro simulations.

R.A.	Dec.	Target Name	Det.	Grating	Exp.Time (ks)
03:38:51.90	-35:35:40.00	NGC 1404	ACIS-S	NONE	400
03:39:16.40	-35:39:40.20	NGC 1404 tail	ACIS-S	NONE	100

Subject Category: CLUSTERS OF GALAXIES

Proposal Number: 15800803

Title: Setting the Scale: Supporting precision cluster cosmology with Chandra observations of low-z lensing clusters

Type: GO Total Time (ks): 65

PI Name: Adam Mantz

The most critical systematic uncertainty now facing galaxy cluster cosmology is in the overall calibration of cluster masses. A large cluster sample having both gravitational lensing and X-ray data can provide an unbiased calibration for X-ray mass proxies, which can then be applied to clusters which lack lensing data, effectively overcoming this obstacle. We propose Chandra observations of 12 clusters at low redshift to complete the X-ray coverage of a sample of 130 ROSAT clusters which have lensing data. An associated archival project seeks to exploit the full sample; together, they will provide a percent-level constraint on the mass calibration, enabling constraints of unprecedented precision from clusters.

R.A.	Dec.	Target Name	Det.	Grating	Exp.Time (ks)
09:12:29.80	+15:56:34.80	A763	ACIS-I	NONE	5
14:31:03.60	+25:37:40.80	A1927	ACIS-I	NONE	5
15:20:53.00	+48:40:19.20	A2064	ACIS-I	NONE	5
10:16:20.40	+33:38:27.60	A961	ACIS-I	NONE	5
08:28:04.60	+44:45:50.40	A667	ACIS-I	NONE	5
01:32:40.90	-08:04:20.00	RXJ0132.6-0804	ACIS-I	NONE	6
14:21:42.70	+37:17:56.40	A1902	ACIS-I	NONE	5
10:50:35.50	-02:36:00.00	RXJ1050.5-0236	ACIS-I	NONE	6
05:30:38.40	-22:26:53.90	RXJ0530.6-2226	ACIS-I	NONE	5
01:06:52.40	-02:29:24.00	RXJ0106.8-0229	ACIS-I	NONE	7
20:43:12.50	-21:44:06.00	RXJ2043.2-2144	ACIS-I	NONE	6
05:07:45.70	-09:15:16.00	RXJ0507.7-0915	ACIS-I	NONE	5

Subject Category: CLUSTERS OF GALAXIES

Proposal Number: 15800858

Title: Clusters, Galaxies, and AGN in HST Frontier Fields

Type: LP Total Time (ks): 520

PI Name: Christine Jones

We propose deep Chandra ACIS-I observations for three HST Frontier Field clusters to obtain 80k source counts for each cluster. The Frontier cluster A2744 already has 80k counts. We also propose JVLA observations for two Frontier clusters and have approved JVLA observations for a third. We will combine the HST cluster lensing mass maps with deep Chandra, HST, and Spitzer imaging, radio and SZ maps, extensive optical spectroscopy, and numerical simulations to understand the physics of the mergers, the transformations of cluster galaxies, and the generation of radio halos and relics in all four HST Frontier clusters that will be observed in HST Cycles 21/22. The combination of Chandra and HST imaging in the parallel fields will test if galaxy mergers play a dominant role in triggering AGN.

R.A.	Dec.	Target Name	Det.	Grating	Exp.Time (ks)
07:17:32.00	+37:45:32.50	MACSJ0717.5+3745	ACIS-I	NONE	71
04:16:08.60	-24:04:40.60	MACSJ0416.1-2403	ACIS-I	NONE	217
11:49:35.10	+22:24:18.40	MACSJ1149.5+2223	ACIS-I	NONE	232

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