Accepted Cycle 14 Observing Proposals

CLUSTERS OF GALAXIES

Proposal Number	Subject Category	PI Name	Title
14800191	CLUSTERS OF GALAXIES	Gastaldello	The front in Abell 1033, a cluster with a speeding BCG
14800226	CLUSTERS OF GALAXIES	Wong	Mapping the nearest non-cool core cluster out to R200
14800358	CLUSTERS OF GALAXIES	Croston	The strongest shock around an FRII radio galaxy?
14800360	CLUSTERS OF GALAXIES	Tozzi	Extreme constraints on ICM physics and cosmology: a deep observation of XMMUJ0044, the most distant massive cluster
14800365	CLUSTERS OF GALAXIES	Jones	A Chandra-Planck Legacy Program for Massive Clusters of Galaxies
14800401	CLUSTERS OF GALAXIES	Miller	TO THE OUTER LIMITS OF CLUSTERS WITH CHANDRA AND SUZAKU
14800434	CLUSTERS OF GALAXIES	Randall	A Detailed Study of the Longest Known Ram Pressure Stripped Tail with Deep Chandra Observations of M86
14800485	CLUSTERS OF GALAXIES	Randall	Understanding the Nature and Environment of Radio Relics
14800490	CLUSTERS OF GALAXIES	Reiprich	COMPLETING eHIFLUGCS: THE ULTIMATE PRECISE AND ACCURATE LOCAL BASELINE
14800534	CLUSTERS OF GALAXIES	Brodwin	X-ray Observations of IDCS J1426.5+3508: A Very Massive, SZ-detected Galaxy Cluster at z=1.75
14800651	CLUSTERS OF GALAXIES	Clarke	Shock and Cold Front with a Tail? The Extreme Relic Cluster Abell 2443
14800671	CLUSTERS OF GALAXIES	Russell	Cold fronts, cavities and the disintegrating cool core in the merging galaxy group RXJ0751.3+5012
14800737	CLUSTERS OF GALAXIES	van Weeren	The 'toothbrush-cluster': probing particle acceleration by merger induced shock waves
14800791	CLUSTERS OF GALAXIES	Allen	Tracing a merger from start to finish in Abell 85
14800795	CLUSTERS OF GALAXIES	Giacintucci	RXCJ1514.9-1523: a new USSRH?
14800808	CLUSTERS OF GALAXIES	Kraft	Extreme Cluster Mergers - Deep Chandra Follow-up to Two Massive Cluster Mergers at Redshift 0.25 Detected by Planck
14800815	CLUSTERS OF GALAXIES	Werner	Resolving the nearest cold front in the sky: the cleanest experimental tool to study detailed ICM physics
14800899	CLUSTERS OF GALAXIES	Vrtilek	Hot gas in spiral-dominated groups: does HGC 16 have a halo?
14800901	CLUSTERS OF GALAXIES	Walker	Joint Chandra and Suzaku exploration of the outskirts of the nearby, X-ray bright Centaurus cluster
14800903	CLUSTERS OF GALAXIES	Markevitch	RESOLVING KELVIN-HELMHOLTZ INSTABILITIES IN CLUSTER COLD FRONTS
14800973	CLUSTERS OF GALAXIES	Murray	X-ray Properties of Massive Clusters in the Local Universe
14800974	CLUSTERS OF GALAXIES	Murray	The radio relic/cluster merger connection

Subject Category: CLUSTERS OF GALAXIES

Proposal Number: 14800191

Title: The front in Abell 1033, a cluster with a speeding BCG

PI Name: Fabio Gastaldello

We propose a 64 ks Chandra observation of the candidate merging cluster Abell 1033 to investigate the nature of a surface brightness discontinuity (likely a cold front) seen in the ROSAT HRI image. Yet another puzzling piece of evidence of the disturbed nature of the system is the high peculiar velocity of its brightest galaxy, which is consistent with a merger along the line of sight, at odds with the sharp appearance of the front usually associated with mergers mainly in the plane of the sky. The Chandra observation will shed light on this issue and may revise our understanding of the formation of cold fronts.

R.A.	Dec.	Target Name	Det.	Grating	Exp.Time
10:31:45.40	+35:02:15.70	Abell 1033	ACIS-I	NONE	64

Subject Category: CLUSTERS OF GALAXIES

Proposal Number: 14800226

Title: Mapping the nearest non-cool core cluster out to R200

PI Name: Ka-Wah Wong

We propose to carry out mosaic observations (49 ks) of the Antlia cluster, the third closest galaxy cluster highly ignored by the X-ray community, out to R200. It is the nearest non-cool core cluster with a similarly low temperature as the cool core Virgo Cluster, allowing us to make a direct comparison to the cool core counterpart in our neighborhood. Physical properties such as density and temperature will be studied around the virial radius. These data can place important constraints on theoretical models of clusters and their environments. We will test models for clumping, electron-ion equipartition, and non-equilibrium ionization. The excellent Chandra spatial resolution combining with the low Suzaku background allows this measurement.

R.A.	Dec.	Target Name	Det.	Grating	Exp.Time
10:37:23.00	-35:19:39.70	Antlia Cluster E5	ACIS-I	NONE	7
10:35:55.00	-35:19:39.70	Antlia E4	ACIS-I	NONE	7
10:40:20.00	-35:19:39.70	Antlia EB	ACIS-I	NONE	7
10:34:27.00	-35:19:39.70	Antlia E3	ACIS-I	NONE	7
10:32:59.00	-35:19:39.70	Antlia E2	ACIS-I	NONE	7
10:31:30.00	-35:19:39.70	Antlia E1	ACIS-I	NONE	7

Subject Category: CLUSTERS OF GALAXIES

Proposal Number: 14800358

Title: The strongest shock around an FRII radio galaxy?

PI Name: Judith Croston

We have detected a 200-kpc scale shock in the intracluster medium surrounding the FRII radio galaxy 3C 444 in a short Chandra observation. Our existing data have allowed us to identify a sharp surface brightness discontinuity and a clear temperature jump, which corresponds to a Mach number of at least 1.7. This is the clearest example to date of a shock associated with a powerful FRII radio galaxy, and potentially the strongest cluster-scale radio-galaxy shock detected to date. We request a deep Chandra observation in order to obtain accurate measurements of the shock conditions, which will enable us to confirm the shock strength and carry out the first detailed investigation of the environmental impact of an FRII radio galaxy.

R.A.	Dec.	Target Name	Det.	Grating	Exp.Time
22:14:25.70	-17:01:36.40	3C 444	ACIS-S	NONE	200

Subject Category: CLUSTERS OF GALAXIES

Proposal Number: 14800360

Title: Extreme constraints on ICM physics and cosmology: a deep observation of XMMUJ0044, the most distant massive cluster

PI Name: Paolo Tozzi

We propose a deep (380 ks) Chandra observation of the distant galaxy cluster XMMUJ0044 at z=1.58. With this observation we will push detailed studies of X-ray clusters to the edge of the current discovery limit, by measuring global temperature and Fe abundance, gas and total mass, putting strong constraints on the time formation of cool core, on the chemical enrichment time scale, on the relation between ICM and galaxy population, and deriving the best constraint to the standard Lambda-CDM model attainable at present. These results, achievable only with Chandra, are secured by a first X-ray characterization of XMMUJ0044 based on XMM data, and will constitute an unrivaled reference for distant cluster studies until the next generation of high-angular resolution X-ray satellites.

R.A.	Dec.	Target Name	Det.	Grating	Exp.Time
00:44:05.20	-20:33:59.70	XMMUJ0044.0-2033	ACIS-S	NONE	380

Subject Category: CLUSTERS OF GALAXIES

Proposal Number: 14800365

Title: A Chandra-Planck Legacy Program for Massive Clusters of Galaxies

PI Name: Christine Jones

ESA's Planck Mission has provided a large, statistically representative sample of very massive clusters, detected over the full sky through their SZ effect. The Planck clusters are sufficiently X-ray bright that for all 165 z<0.35 clusters, Chandra will collect 10,000 source counts to characterize each cluster's dynamical state, including merger properties, measure cluster masses and mass proxies and define local cluster mass and temperature functions. Chandra observations will provide a benchmark at low redshifts for comparison to high redshift clusters and to cosmological N-body simulations. Our team is expert in the analysis of X-ray and SZ data and in theory, simulations, lensing, and radio studies of clusters. We plan to make our cluster analysis products available to the community.

R.A.	Dec.	Target Name	Det.	Grating	Exp.Time
10:43:24.80	-20:37:18.00	G106.73-83.22	ACIS-I	NONE	12
21:35:19.90	+01:23:14.50	G055.97-34.88	ACIS-I	NONE	20
18:04:29.70	+18:04:29.70	G036.72+14.92	ACIS-I	NONE	10
05:16:37.50	-54:31:31.80	G262.25-35.36	ACIS-I	NONE	22
06:16:19.80	-21:57:35.00	G229.21-17.24	ACIS-I	NONE	24
22:18:41.30	-38:54:16.80	G002.74-56.18	ACIS-I	NONE	11
19:47:09.30	-76:23:52.00	G318.13-29.57	ACIS-I	NONE	20
21:27:03.50	-12:09:19.00	G039.85-39.98	ACIS-I	NONE	15
19:38:19.70	+54:09:26.30	G086.45+15.29	ACIS-I	NONE	15
10:22:27.30	+50:06:16.30	G163.72+53.53	ACIS-I	NONE	14
22:23:49.30	-01:37:13.20	G062.42-46.41	ACIS-I	NONE	9
20:23:24.30	-55:34:26.50	G342.31-34.90	ACIS-I	NONE	21
09:45:26.20	-08:40:06.00	G244.69+32.49	ACIS-I	NONE	16
02:25:56.00	-41:54:53.00	G256.45-65.71	ACIS-I	NONE	15
05:32:59.40	-37:01:39.60	G241.74-30.88	ACIS-I	NONE	25
03:03:53.10	-77:52:14.40	G294.66-37.02	ACIS-I	NONE	34
10:23:44.10	+49:08:17.00	G165.08+54.11	ACIS-I	NONE	10
22:17:46.10	-35:43:22.20	G008.44-56.35	ACIS-I	NONE	12
10:39:28.10	+05:10:06.00	G241.85+51.53	ACIS-I	NONE	14
17:47:18.00	+45:13:30.70	G071.61+29.79	ACIS-I	NONE	21
11:59:23.00	+49:47:39.00	G143.24+65.21	ACIS-I	NONE	22
19:34:54.00	-50:53:18.80	G347.18-27.35	ACIS-I	NONE	25
05:25:50.00	-47:14:38.30	G253.47-33.72	ACIS-I	NONE	18
13:15:06.60	+51:49:27.20	G114.33+64.87	ACIS-I	NONE	31
23:39:44.00	-85:10:33.00	G304.67-31.66	ACIS-I	NONE	23
06:16:29.50	-39:48:28.80	G247.17-23.32	ACIS-I	NONE	17
12:36:57.40	+63:11:08.00	G125.70+53.85	ACIS-I	NONE	29
09:20:24.80	+30:30:09.20	G195.62+44.05	ACIS-I	NONE	38
14:14:05.30	+71:17:36.50	G113.82+44.35	ACIS-I	NONE	19
18:19:55.30	+57:09:57.30	G085.99+26.71	ACIS-I	NONE	35
10:00:02.10	-30:15:55.80	G264.41+19.48	ACIS-I	NONE	31
20:51:50.20	-58:45:23.00	G345.40-39.34	ACIS-I	NONE	30
12:01:04.00	-39:52:11.00	G292.51+21.98	ACIS-I	NONE	45
19:14:36.90	-59:28:19.90	G337.09-25.97	ACIS-I	NONE	25
09:38:21.40	+52:02:38.40	G164.61+46.39	ACIS-I	NONE	42
12:59:37.60	+60:04:41.90	G121.11+57.01	ACIS-I	NONE	44
06:21:55.00	+74:41:38.40	G139.59+24.18	ACIS-I	NONE	18
11:11:37.10	+40:50:01.90	G172.88+65.32	ACIS-I	NONE	12
05:10:13.00	-45:19:29.00	G250.90-36.25	ACIS-I	NONE	16
05:31:34.70	-75:11:26.40	G286.58-31.25	ACIS-I	NONE	24
18:54:06.00	+68:22:15.00	G098.95+24.86	ACIS-I	NONE	17
06:37:19.50	-48:28:50.40	G257.34-22.18	ACIS-I	NONE	25
21:04:22.90	-41:21:46.00	G000.44-41.83	ACIS-I	NONE	14
11:42:37.40	+58:32:14.30	G139.19+56.35	ACIS-I	NONE	33
12:15:28.80	-39:01:47.00	G295.33+23.33	ACIS-I	NONE	15

Subject Category: CLUSTERS OF GALAXIES

Proposal Number: 14800401

Title: TO THE OUTER LIMITS OF CLUSTERS WITH CHANDRA AND SUZAKU

PI Name: Eric Miller

We propose ACIS-I snapshot observations of the outskirts of two galaxy clusters. When combined with awarded Suzaku observations of overlapping regions, these data will enable us to identify X-ray point sources (cluster and background AGN) that are undetectable by Suzaku and that dominate the uncertainty in the X-ray background. The combination of Chandra and Suzaku data is vital to our search for non-equilibrium structures in these seemingly relaxed systems and our quest to understand the physics of cluster growth. In addition, we will obtain a full census of bright cluster AGN out to r200, thereby improving constraints on evolution of the AGN fraction in these systems.

R.A.	Dec.	Target Name	Det.	Grating	Exp.Time
23:25:19.60	-12:07:28.20	A2597	ACIS-I	NONE	20
08:30:59.20	+65:50:27.70	A665	ACIS-I	NONE	20

Subject Category: CLUSTERS OF GALAXIES

Proposal Number: 14800434

Title: A Detailed Study of the Longest Known Ram Pressure Stripped Tail with Deep Chandra Observations of M86

PI Name: Scott Randall

We propose deep Chandra observations of the ram pressure stripped tail in M86, the longest ram pressure stripped tail known. M86 is nearby, in the Virgo cluster (~17 Mpc), and is X-ray bright. With Chandra's high spatial resolution we will image fine detail in the tail, and map the temperature and abundance structure along the tail. We will determine the origin of the stripped gas, place limits on gas mixing in the tail with the ICM, and ultimately place constrains on ICM microphysics through comparisons with detailed hydrodynamical simulations.

R.A.	Dec.	Target Name	Det.	Grating	Exp.Time
12:25:45.90	+13:04:52.00	M86 Inner Tail	ACIS-I	NONE	150
12:25:02.30	+13:16:54.60	M86 Outer Tail	ACIS-I	NONE	200

Subject Category: CLUSTERS OF GALAXIES

Proposal Number: 14800485

Title: Understanding the Nature and Environment of Radio Relics

PI Name: Scott Randall

Radio relics are diffuse radio source that reside in the outskirts of galaxy clusters, thought to arise from particle acceleration during mergers. New low frequency radio observatories are revealing a new class of ultra-steep source (USS) radio relics, and upcoming surveys are expected to find hundreds to thousands of such sources. We propose to observe a pilot sample of four clusters containing USS relics, to verify their connection to merging clusters and search for correlations with X-ray shocks. X-ray observations of such sources are very rare, and only two exist with confirmed shock detections. Our goal is to image substructure in the ICM, and to roughly map its thermal structure. Results will be compared with low frequency radio observations to constrain relic formation models.

R.A.	Dec.	Target Name	Det.	Grating	Exp.Time
01:08:03.00	+54:05:48.70	CIZA J0107.7+5408	ACIS-I	NONE	23

Subject Category: CLUSTERS OF GALAXIES

Proposal Number: 14800490

Title: COMPLETING eHIFLUGCS: THE ULTIMATE PRECISE AND ACCURATE LOCAL BASELINE

PI Name: Thomas Reiprich

Currently, the largest complete local cluster sample with full high quality X-ray coverage is HIFLUGCS. Its selection is based on the ROSAT All-Sky Survey and complete X-ray follow-up has been performed with Chandra and XMM-Newton, resulting in numerous applications in cluster physics and cosmology by several research groups. The combination of high completeness, large sample size, and high quality follow-up has been crucial for this wide applicability. Here, we propose a threefold increase in sample size with a new complete high quality sample, eHIFLUGCS. We demonstrate that this significantly increased statistics will enable substantial improvements in precision for several studies as well as qualitatively new tests.

R.A.	Dec.	Target Name	Det.	Grating	Exp.Time
13:49:27.60	+28:06:21.60	A1800	ACIS-I	NONE	6
01:20:58.80	-13:51:32.40	CAN 010	ACIS-I	NONE	8
05:25:32.90	-31:35:45.60	A3341	ACIS-I	NONE	9
00:52:44.90	-80:15:57.60	A2837	ACIS-I	NONE	8
00:11:47.00	+32:25:12.00	A7	ACIS-I	NONE	8
12:05:09.60	+39:20:49.20	RBS1066	ACIS-I	NONE	8
08:25:26.60	+47:07:55.20	A655	ACIS-I	NONE	8
15:39:48.50	+30:42:57.60	A2110	ACIS-I	NONE	8
22:20:33.60	-35:09:54.00	A3866	ACIS-I	NONE	9
18:11:00.10	+49:54:39.60	Z8338	ACIS-I	NONE	8
00:20:31.90	+28:39:46.80	A21	ACIS-I	NONE	9
21:46:57.60	-43:54:36.00	A3809	ACIS-I	NONE	11
10:13:40.80	-00:54:52.00	A0957	ACIS-I	NONE	12
08:23:11.50	+04:21:21.60	Z1665	ACIS-I	NONE	10
15:11:23.50	+06:19:08.40	A2033	ACIS-I	NONE	9

Subject Category: CLUSTERS OF GALAXIES

Proposal Number: 14800534

Title: X-ray Observations of IDCS J1426.5+3508: A Very Massive, SZ-detected Galaxy Cluster at z=1.75

PI Name: Mark Brodwin

We propose ACIS-I observations of IDCS J1426.5+3508, which at z=1.75 is the most massive cluster yet discovered at z > 1.4 and the first cluster at this epoch for which the Sunyaev-Zel'dovich (SZ) effect has been observed. It also contains a rare strong gravitational arc. The primary goals of this proposal are to (1) measure a precise X-ray temperature for this unique cluster, and (2) extend X-ray and SZ cluster scaling relations, critical for cluster cosmology, to z=1.75. With these data we'll also study the ICM at this early epoch, make a Tx-based assessment of the cosmological significance of this cluster, and measure the gas mass profile to further constrain this unexpected lensing system, which we observe at a redshift where *no* strong-lensing clusters should exist.

R.A.	Dec.	Target Name	Det.	Grating	Exp.Time
14:26:32.90	+35:08:23.60	IDCS J1426.5+3508	ACIS-I	NONE	100

Subject Category: CLUSTERS OF GALAXIES

Proposal Number: 14800651

Title: Shock and Cold Front with a Tail? The Extreme Relic Cluster Abell 2443

PI Name: Tracy Clarke

We propose a 100 ks ACIS-I exposure of the extreme radio relic cluster A2443. This cluster contains a (rare) ultra-steep spectrum (USS) relic which likely traces a merger-induced shock. Our 16 ks Cycle 12 observation reveals a ram-pressure stripped tail and two surface brightness edges which are consistent with a cold front near the core and shock near the relic. The proposed observation is designed to confirm the nature of these edges and examine the merger/USS relic connection in view of better understanding how these USS sources are tied to the merger energetics. USS relics are expected to be ubiquitous in upcoming low frequency surveys and have significance for particle acceleration studies and for tracing large scale structure evolution.

R.A.	Dec.	Target Name	Det.	Grating	Exp.Time
22:26:07.50	+17:21:54.00	Abell 2443	ACIS-I	NONE	100

Subject Category: CLUSTERS OF GALAXIES

Proposal Number: 14800671

Title: Cold fronts, cavities and the disintegrating cool core in the merging galaxy group RXJ0751.3+5012

PI Name: Helen Russell

We propose a 100 ks Chandra observation of the nearby object RXJ0751.3+5012 which hosts a major merger between two large galaxy groups. A short, archival XMM-Newton observation of RXJ0751.3+5012 shows the northern group hosts a bright, dense core with a sharp drop in surface brightness along the leading edge and a long tail of ram pressure stripped material. The southern group appears less disrupted but has a 100 kpc long surface brightness edge indicating it has been perturbed by the close passage of the other group. The proposed observation of this group merger with Chandra's subarcsecond resolution will allow us to resolve and characterise the surface brightness edges and to investigate heating, metal enrichment and transport processes in the intragroup medium.

R.A.	Dec.	Target Name	Det.	Grating	Exp.Time
07:51:19.90	+50:14:07.00	RXJ0751.3+5012	ACIS-I	NONE	100

Subject Category: CLUSTERS OF GALAXIES

Proposal Number: 14800737

Title: The 'toothbrush-cluster': probing particle acceleration by merger induced shock waves

PI Name: Reinout van Weeren

We have discovered a spectacular merging galaxy cluster hosting a 2-Mpc elongated radio source, suggesting particle acceleration at merger shocks. The large straight extent is however very difficult to explain with current merger scenarios and a very high Mach number of 4.5 is required to explain the radio spectral index. We therefore argue that this cluster is a key object to test current models of shock acceleration and cluster formation. The proposed Chandra+EVLA observations will address the following: (i) is there a compelling need for a more sophisticated particle acceleration mechanism than standard diffusive shock acceleration? And (ii) are we witnessing a very special configuration consisting of multiple merger events that collectively conspire to yield such a linear shock?

R.A.	Dec.	Target Name	Det.	Grating	Exp.Time
06:03:17.00	+42:15:08.40	1RXS J060313.4+421231	ACIS-I	NONE	200

Subject Category: CLUSTERS OF GALAXIES

Proposal Number: 14800791

Title: Tracing a merger from start to finish in Abell 85

PI Name: Steven Allen

We propose exposures with Chandra and Suzaku in Abell 85 to trace the impact of a galaxy group merging with a galaxy cluster at multiple scales. Existing observations of Abell 85 reveal an infalling galaxy group ~300 kpc to the south of the main cluster moving supersonically through the ICM. Stripped gas is observed trailing behind this group to distances of 2 Mpc. We will investigate interactions between this group and the main cluster by observing the shocks associated with the group's motion and the properties of stripped gas. We will be able to measure the properties of the stripped gas from the group's current location out to the virial radius by combining the data from both telescopes. These observations will provide key insights into how the largest structures form.

R.A.	Dec.	Target Name	Det.	Grating	Exp.Time
00:41:37.00	-09:25:45.40	Abell 85	ACIS-I	NONE	80
00:41:51.20	-09:23:47.40	Abell 85	ACIS-I	NONE	80

Subject Category: CLUSTERS OF GALAXIES

Proposal Number: 14800795

Title: RXCJ1514.9-1523: a new USSRH?

PI Name: Simona Giacintucci

Giant radio halos, found in some merging galaxy clusters, reveal the presence of cosmic rays and magnetic fields - possible significant contributors to the cluster energy budget. Current evidence points to electron reacceleration by merger turbulence as a possible origin of such halos. Only massive, major mergers can produce halos seen at GHz frequencies; more common, minor mergers are expected to produce less energetic electrons that emit at lower frequencies. We recently discovered two such ultra-steep spectrum radio halos (USSRHs) - the first members of a new, possibly dominant kind of halos. They proved to be very interesting in X-rays. RXCJ1514 may be another USSRH, and we propose a joint Chandra-EVLA observation to study its dynamic state and confirm the very steep radio spectrum.

R.A.	Dec.	Target Name	Det.	Grating	Exp.Time
15:14:58.00	-15:23:10.00	RXCJ1514.9-1523	ACIS-I	NONE	60

Subject Category: CLUSTERS OF GALAXIES

Proposal Number: 14800808

Title: Extreme Cluster Mergers - Deep Chandra Follow-up to Two Massive Cluster Mergers at Redshift 0.25 Detected by Planck

PI Name: Ralph Kraft

The Planck collaboration released their first catalog of 189 cluster candidates last year. We examined the archival Chandra data on these clusters to find examples of highly disturbed and multi-peaked morphologies indicative of massive, highly supersonic mergers for deep follow-up. The two best examples are Abell S0592 (z=0.2216) and RXC J0528.9-3927 (z=0.2839), two 9 keV clusters with highly disturbed X-ray morphologies. We propose 90 ks Chandra/ACIS-I observations on each cluster to measure the gas temperature and pressure across surface brightness discontinuities, estimate velocities, and compare the morphologies with simulations to elucidate their dynamical histories. Understanding extreme mergers is critical to fully interpreting SZ clusters for cosmology.

R.A.	Dec.	Target Name	Det.	Grating	Exp.Time
06:38:51.20	-53:57:47.00	Abell S0592	ACIS-I	NONE	90
05:28:53.00	-39:28:18.00	RXC J0528.9-3927	ACIS-I	NONE	90

Subject Category: CLUSTERS OF GALAXIES

Proposal Number: 14800815

Title: Resolving the nearest cold front in the sky: the cleanest experimental tool to study detailed ICM physics

PI Name: Norbert Werner

We propose a very deep legacy-class observation of the nearest, best resolved cold front in the sky which lies 90 kpc to the North of M87. Cold fronts are known to be remarkably sharp, with gas density and temperature discontinuities several times sharper than the Coulomb mean free path. The proposed observation will provide an extraordinary improvement in resolution (resolving ~80 pc scales), allowing to study the cold front interface in unprecedented detail. Cold fronts provide a relatively simple experimental setup - a unique tool to study ICM physics. The proposed observation will place crucial constraints on fundamental physical processes shaping cold fronts, such as: growth of instabilities in the ICM, intra-cluster magnetic fields, gas velocities, conduction and viscous stresses.

R.A.	Dec.	Target Name	Det.	Grating	Exp.Time
12:29:56.30	+12:38:39.60	Virgo cold front	ACIS-I	NONE	500

Subject Category: CLUSTERS OF GALAXIES

Proposal Number: 14800899

Title: Hot gas in spiral-dominated groups: does HGC 16 have a halo?

PI Name: Jan Vrtilek

The group environment --- the locus of most galaxies in the present-day Universe --- is particularly suitable for the study of a central process of galaxian evolution: the merging of spirals to form ellipticals. The mechanism of formation of hot halos, although clearly linked to galaxy evolution, is not well understood in any groups, yet in spiral-dominated groups even the general presence of a hot intergalactic medium is not clearly established. We propose to observe HCG 16, a compact spiral-dominated group in the early phase of merging, selected for proximity and X-ray brightness. Our deep integration will clarify the distribution of diffuse intragroup gas; examine its temperature and heavy element abundances as a clue to its origins; and identify shocks, fronts, and gas stripping.

R.A.	Dec.	Target Name	Det.	Grating	Exp.Time
02:09:32.00	-10:09:24.00	HCG 16	ACIS-S	NONE	150

Subject Category: CLUSTERS OF GALAXIES

Proposal Number: 14800901

Title: Joint Chandra and Suzaku exploration of the outskirts of the nearby, X-ray bright Centaurus cluster

PI Name: Stephen Walker

We propose brief Chandra observations of the outskirts of the Centaurus cluster to complement our existing Suzaku observations. Chandra's greater sensitivity allows point sources to be identified to a much lower threshold flux, thus allowing the cosmic X-ray background (CXB) to resolved with greater depth, significantly reducing the spatial fluctuations in the CXB level which present the main source of systematic error limiting the precision with which Suzaku can observe the properties of the outskirts of galaxy clusters.

R.A.	Dec.	Target Name	Det.	Grating	Exp.Time
12:46:43.20	-40:27:22.10	Centaurus Cluster	ACIS-I	NONE	10
12:45:58.40	-40:11:16.30	Centaurus Cluster	ACIS-I	NONE	10
12:45:18.90	-39:55:10.20	Centaurus Cluster	ACIS-I	NONE	10
12:44:36.50	-39:38:43.90	Centaurus Cluster	ACIS-I	NONE	10

Subject Category: CLUSTERS OF GALAXIES

Proposal Number: 14800903

Title: RESOLVING KELVIN-HELMHOLTZ INSTABILITIES IN CLUSTER COLD FRONTS

PI Name: Maxim Markevitch

Understanding the physics of the intracluster medium is essential for use of clusters as precision cosmology tools. Thermal conductivity, viscosity, strength and structure of magnetic fields affect thermodynamics of the ICM on scales from cool cores to the outskirts by regulating turbulence, mixing, heating of cool cores and accelerating cosmic rays. Cold fronts in merging and sloshing clusters offer a unique experimental setup to study these unknown ICM properties. We propose moderately deep reobservations of two clusters, A2142 and A2319, whose Chandra images hint at the onset of Kelvin-Helmholtz instabilities at their prominent cold fronts. Our simulations showed that these instabilities should be suppressed by viscosity and magnetic field draping, and we will constrain these effects.

R.A.	Dec.	Target Name	Det.	Grating	Exp.Time
15:58:19.60	+27:13:34.00	A2142	ACIS-I	NONE	165
19:21:15.00	+43:54:59.00	A2319	ACIS-I	NONE	80

Subject Category: CLUSTERS OF GALAXIES

Proposal Number: 14800973

Title: X-ray Properties of Massive Clusters in the Local Universe

PI Name: Stephen Murray

SZ surveys provide cluster samples with close to an unbiased mass-limited selection. Planck has provided a large, statistically representative cluster sample with masses from 10^14 to nearly 2x10^15 M_sun. By using the Planck sample which includes the rare, very massive clusters, we can best define local Universe benchmarks for cosmological measurements. We propose to characterize the dynamical state for two Planck clusters, including measuring masses and mass proxies and merger properties. Since these clusters are bright, Chandra will collect ~10,000 source counts in 10 ks. Combining these observations with a larger sample of Planck clusters, observed by or proposed in AO14 for Chandra, will provide benchmarks at low z for comparison to high z cluster samples and to N-body simulations.

R.A.	Dec.	Target Name	Det.	Grating	Exp.Time
12:00:25.50	+03:20:09.50	G273.64+63.28	ACIS-I	NONE	10
11:30:21.00	-14:36:10.20	G275.21+43.92	ACIS-I	NONE	10

Subject Category: CLUSTERS OF GALAXIES

Proposal Number: 14800974

Title: The radio relic/cluster merger connection

PI Name: Stephen Murray

Galaxy clusters grow by mergers with other clusters and groups. These mergers create shocks which probably accelerate particles creating radio relics. We recently discovered previously unknown radio relics by examination of archival WSRT and NVSS data and cross-correlating with RASS. These relics are selected from their radio, not X-ray, properties, and are not biased to the most massive systems. We propose Chandra observations of the two clusters in this sample with little or no existing data to complete the sample. Modelling of the X-ray data can yield the mass ratio and the impact parameter of the merger. Simulations make specific prediction about the location of the relics and the dynamical state of the cluster which can now be tested.

R.A.	Dec.	Target Name	Det.	Grating	Exp.Time
09:09:27.80	+51:32:19.70	A746	ACIS-I	NONE	27
12:47:47.20	-02:47:50.20	A1612	ACIS-I	NONE	31

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