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Proposal Number: 10800015

Title: Bow shock in A754

PI Name: Stephen Murray

We will obtain accurate temperatures across the apparent shock front in A754, in order to confirm that this is indeed a shock and to determine its velocity. A shock at this location, combined with the existing and forthcoming radio halo data at several frequencies, would enable a number of interesting tests.

Proposal Number: 10800028

Title: Merging Clusters in DEEP2 Field 4

PI Name: Stephen Murray

A pair of galaxy clusters in the DEEP2 Field 4 region has been found using the Chandra DEEP2 survey data. One cluster is a previously known Palomar Deep Cluster Survey object, the other is new. This observation will determine whether these clusters are merging and will provide sufficient depth to determine temperature and mass for both.

Proposal Number: 10800035

Title: Survey of AGN outbursts in clusters

PI Name: Stephen Murray

While outbursts from active galactic nuclei have been found in many clusters of galaxies, an unbiased survey is required to study the life cycles of outbursts and to assess their impacts on clusters as a population. We propose to undertake such a survey, using a sample selected from the HIFLUGCS catalog. The two clusters to be observed here are part of our sample.

Proposal Number: 10800043

Title: Chandra observations of flux-limited sample of low-redshift galaxy clusters

PI Name: Stephen Murray

We propose to obtain 10ksec ACIS-I exposures for low-redshift galaxy clusters. These observations will provide complete Chandra coverage for a flux-limited sample of 110 clusters with flux > 9e-12 erg/s/cm^2 selected in the ROSAT All-Sky Survey at |b|>20 deg. These observation will be used for accurate determinations of the ICM temperature and mass, and for study of X-ray substructures in the central regions.

Proposal Number: 10800166

Title: The X-ray gaseous environment of dying radio sources

PI Name: Matteo Murgia

We propose Chandra observations of a sample of five galaxy clusters which harbor dying radio galaxies recently discovered by us in the radio. Dying radio sources are very rare objects. We argue that their intriguing association with clusters implies that the pressure of the dense intra-cluster medium (perhaps a cooling flow) prevents quick liquidation of a dying radio lobe through adiabatic expansion. We will use the proposed observations to test this hypothesis and to compare the actual fading radio structures with the X-ray image. We intend to investigate a possible correlation between the duration of the relic phase of the de-energized radio lobes and the pressure of the exter nal medium in which they are embedded.

Proposal Number: 10800174

Title: Chandra Observations of Abell 3653, the Cluster with the Largest Known cD Peculiar Velocity

PI Name: Craig Sarazin

We propose high-resolution Chandra observations of the central cool core of Abell 3653, the rich cluster with the largest known cD galaxy peculiar velocity. Previous Chandra observations of A2670 and A2107, two other clusters with large cD motions, have shown that they are merging systems. We will search for evidence of a merger in A3653. We will compare the core velocity from the X-ray observations with the optical z of the cD. We will study hydrodynamical instabilities (e.g., convection and the Kelvin-Helmholtz instability) that are expected around the core. One might expect the cooling core to be destroyed by these instabilities. We will also study the interaction between the cD galaxy and other cluster galaxies, which gives information on cD formation processes.

Proposal Number: 10800217

Title: Characterisation of ISCS J1438+3414, a z=1.41 galaxy cluster free of X-ray selection bias

PI Name: Stefano Andreon

High-redshift galaxy clusters are scarce, with only a few systems known at z > 1, and the highest spectroscopically confirmed cluster scoring z=1.45. We ask a 150 ks observation in order to characterise the second most distant cluster of galaxy known thus far, ISCS J1438+3414, at z=1.41, that is also the most distant non-X-ray selected cluster. ISCS J1438+3414, optically-infrared selected, offers a unique opportunity to estimate X-ray scale relationships at z=1.4 free from the biases that affect X-ray selected cluster samples. We will investigate a key question of cluster studies and for the determination of cosmological parameters, namely whether the simple evolution of the cluster scaling relations predicted by the self-similar model is obeyed at z=1.4.

Proposal Number: 10800324

Title: The Remarkably Inefficient AGN Outburst in HCG 62: Total Energy Budget and Lobe Contents

PI Name: David Rafferty

Chandra has revealed cavities in the hot atmospheres of groups and clusters, created by outbursts of the radio sources at their cores. Our understanding of such outbursts has improved greatly over the last few years, but we remain largely ignorant of important details, such as their importance for the preheating problem, particularly at group scales, and the contents of the cavities. We propose a deep, 120 ks observation of a remarkable cavity system in the compact group HCG 62. These data will allow us to place limits on the presence of thermal gas in the cavities, important for models of jet content and evolution, and to accurately quantify the total power budget of the AGN outburst, allowing an assessment of its importance for preheating.

Proposal Number: 10800331

Title: Mapping Dark Matter in the Merging Cluster MACSJ0025.4

PI Name: Roger Morris

Clusters of galaxies are dominated by dark matter. In mergers between massive clusters, the positions of the dark matter and main baryonic components can become separated. In rare cases, it is possible to study the presence of these two components independently. Here we propose to observe a spectacular example of such a system: the extraodinary, high-redshift cluster MACSJ0025.4-1222. Detailed Hubble Space Telescope and Subaru optical data for this system are in hand, and gravitational lensing shows the dominance of dark matter. There remains however one missing link: a detailed mass map of the main baryonic component, the hot X-ray emitting gas. We propose a deep observation to address this issue, and also to produce detailed maps of the thermodynamic state of this unique cluster.

Proposal Number: 10800395

Title: MACSJ1147.3-1252: An extremely X-ray luminous cluster at z=0.58?

PI Name: Harald Ebeling

We propose an exploratory 10 ks ACIS-I observation of MACSJ1147.3-1252, a potentially extremely X-ray luminous galaxy cluster at z=0.58. Discovered first in the LCDCS, the system was recently detected also in the Massive Cluster Survey (MACS). The cluster's RASS flux suggests a total X-ray luminosity comparable to that of Cl0016+16, one of the most X-ray luminous clusters known at z>0.5. Chandra's superb angular resolution will allow us to quantify the degree of contamination from a nearby QSO (1.3 arcmin away from the cluster core) and to accurately determine the cluster luminosity. Deeper observations will be proposed in Cycle 11, should the system's properties confirm its importance for cosmological and cluster evolution studies.

Proposal Number: 10800424

Title: Does AGN heating quench star formation in Brightest Cluster Galaxies?

PI Name: Helen Russell

Recent studies have demonstrated that feedback by AGN has sufficient energy to halt condensation and cooling of the ICM. However recent Spitzer observations have shown that 30-50% of BCGs exhibit star formation and so this feedback is in some cases not sufficiently strong to completely stop condensation. We propose here to observe a few such objects. By comparing the structure and distribution of X-ray gas in BCGs hosting active star formation we will determine the conditions that lead to the failure of AGN feedback to quench condensation and so star formation. The combination of X-ray-derived gas cooling times and estimates of cavity power with IR-derived star formation rates will allow us to study the entire cycle of cooling, star formation and feedback in cluster cool cores.

Proposal Number: 10800487

Title: The Formation of Brightest Cluster Galaxies

PI Name: John Mulchaey

We propose Chandra and HST observations of a unique low redshift cluster in which the Brightest Cluster Galaxy (BCG) is in the process of forming. The Chandra observations will be used to study the impact of BCG formation on the properties of the intracluster medium. We will test whether galaxy merging can destroy cool cores and disrupt hot gas halos. We will also explore the role of intracluster stars in enriching the intracluster medium. The HST observations will be used to search for extended tidal features and young star clusters and to estimate the final stellar mass of the BCG. The low redshift of our target allows a more detailed study of BCG formation than is possible with higher redshift systems.

Proposal Number: 10800488

Title: Completing a combined X-ray/Sunyaev-Zel'dovich effect sample of galaxy clusters

PI Name: Ben Maughan

We propose a 14ks observation of the z=0.279 galaxy cluster A689 in order to measure the global properties and temperature profile, and finish a statistically complete sample of clusters observed with Chandra and in the Sunyaev-Zel'dovich effect (SZE) with OCRA-p. The sample will be used to investigate X-ray/SZE scaling relations - an important step towards using SZE surveys for precision cosmology. A689 is one of the most luminous clusters known but has yet to be observed by Chandra or XMM. It is bright enough to be included in many cluster surveys, but is often excluded because of possible point source contamination. This Chandra observation will measure any such contamination and determine whether A689 should be included in statistically complete cluster samples.

Proposal Number: 10800511

Title: A Chandra baseline for galaxy cluster evolution studies

PI Name: Ben Maughan

We propose to survey a sample of 10 0.04

Proposal Number: 10800565

Title: LoCuSS: An Unbiased Multi-wavelength Study of the Cluster Quadchotomy - Gas Cooling and Cluster Merging at z=0.2

PI Name: Graham Smith

We propose a definitive study of cooling and merging in an unbiased sample of 34 clusters at z=0.2 to address "what are the physical differences between cool-core (CC) non-merging, CC merging, non-CC (NCC) non-merging and NCC merging clusters?". We will compile 4 sub-samples numbering ~5-10 clusters each, and measure the mean properties of each sub-sample. Archival Chandra data is available for 23/34 clusters, however they are biased to the more luminous clusters, and against NCC non-merger clusters. We therefore request ACIS-I observations of the remaining 11 at 20ks/cluster. These data will complete an outstanding multiwavelength dataset spanning SZE, far/mid-IR (Herschel & Spitzer), optical (HST and Subaru), UV (GALEX), X-ray (Chandra), that will become a valuable community resource.

Proposal Number: 10800598

Title: Local versus Large Scale : The Active Galaxy Population in High-Redshift Clusters

PI Name: Lori Lubin

We propose to use Chandra and the VLA to map the active galaxy population in two isolated, relaxed X-ray-selected clusters at z = 0.69 and 0.82, providing a vital comparison to our Cycle 7-9 programs to study high-redshift optically-selected clusters that are embedded in large scale structures or are dynamically active. Combined with our extensive photometric and spectroscopic data, the Chandra/VLA observations allow us to measure the properties of X-ray and radio sources to large clustocentric distances and study host galaxies to determine what causes gas-fueling events. Comparing with our previous studies, we can begin to disentangle the role of large-scale versus local environment in driving galaxy evolution by examining a wide range of cluster masses, dynamics, and spatial scales.

Proposal Number: 10800641

Title: A Deep Image of the Most Powerful Cluster AGN Outburst

PI Name: Brian McNamara

Powerful AGN outbursts in galaxy clusters can release upward of 1E61 erg into the intracluster medium. Events of this magnitude are able to quench cooling flows and drive large-scale outflows that redistribute and heat the gas on cluster-wide scales. The most potent example of this is seen in the z=0.22 cluster MS0735.6+7421, whose powerful shock and cavity system have injected an estimated 6E61 erg of energy into the ICM. We propose to obtain a 500 ksec ACIS image of the cluster to examine in detail the relationships between the shock, cavity, and radio systems, and to investigate the impact of powerful AGN outbursts on the structure of the cluster.

Proposal Number: 10800679

Title: The Origin and Evolution of Fossil Groups

PI Name: Eli Rykoff

We propose snapshot observations of 5 optically selected fossil group candidates. These observations will complete a sample of 15 intermediate-redshift fossil group candidates identified from the maxBCG optical cluster survey, 10 of which are scheduled via Chandra GTO time in Cycle 10. These observations will provide estimates of the diffuse X-ray flux for much deeper XMM-Newton follow-up, and they will also provide an estimate of the plasma temperature. They will also help constrain the predicted relation between BCG dominance and halo formation epoch. This snapshot project requires the spatial resolution of Chandra to separate diffuse emission from point source emission; when combined with the sensitivity of XMM-Newton follow-up, it will optimize the usage of these observatories.

Proposal Number: 10800695

Title: The Hyperluminous Infrared Galaxy IRAS 09104+4109: An Extreme Brightest Cluster Galaxy

PI Name: Kenneth Cavagnolo

We propose a detailed study of the hyperluminous infrared BCG IRAS 09104+4109. This BCG is in the rich cluster MACS J0913.7+4056, and likely hosts a ``changing-look'' AGN and the highest redshift AGN blown bubbles known to date. The environment of the BCG is best described as extreme, with cannibalized companion galaxies, the most powerful radio source of any IRAS object, and an AGN which has established a new beaming direction in the last 70 kyrs. Understanding the relationship of the BCG, AGN, and ICM in this peculiar and unique object will aide in developing better models for coupling together galaxy formation, AGN feedback, and large scale cluster environment. IRAS 09104+4109 is an ideal test case of a very short-lived but highly active stage of cluster and central galaxy formation.

Proposal Number: 10800762

Title: The Role of AGN in Massive Galaxy Formation

PI Name: Spencer Stanford

There is increasing evidence that high rates of star formation in massive galaxies was common in rich environments at z > 1. The leading candidate for quenching the star formation and transforming cluster galaxies into red sequence galaxies is AGN. Therefore we expect to see an increase in AGN incidence in dense environments at z > 1. We propose to systematically determine the incidence of AGN in galaxy clusters at 1 < z < 1.5 using moderately deep ACIS imaging of IR-selected clusters in the Bootes field. In conjunction with extensive data from Spitzer, HST, and Keck, we will test the AGN quenching paradigm for the origin of the stars in massive galaxies.

Proposal Number: 10800770

Title: The distribution and interactions of luminous and dark matter in strong-lensing clusters at z>0.3

PI Name: Harald Ebeling

We propose ACIS-I observations of 11 very X-ray luminous clusters at 0.3

Proposal Number: 10800779

Title: Shocks, Ripples, and Bubbles: A Very Deep Observation of Abell 2052

PI Name: Elizabeth Blanton

The cooling flow cluster A2052 has, arguably, the morphology most similar to the Perseus cluster as seen with Chandra. Two clear bubbles to the N and S of the center of A2052 are filled with the radio lobes associated with 3C 317. Surface brightness discontinuities consistent with shocks with Mach numbers of 1.8 and 1.2 are seen near the cluster center. These may be isothermal shocks. We propose to observe Abell 2052 much more deeply to study these shock features, ripple features due to sound waves that may be found at larger radii, possible ghost bubbles, cooling gas in the bright shells around the radio source that may link the X-ray and H-alpha emission, and possible hot gas within the X-ray holes. We will directly compare the star formation and cooling rates in the cluster center.

Proposal Number: 10800835

Title: A Merger Shock Front due to Subcluster Infall in Abell 2061?

PI Name: Daniel Wik

We propose to observe the cluster Abell 2061, for which there is evidence of current and recent merger activity in its galaxy distribution, non-thermal radio properties, and X-ray morphology. We will image and characterize the merger shock front likely due to an infalling subcluster. Only two other shock fronts have been definitively observed in clusters, both with Chandra. We will determine the cause of the shock, whether it is due to the subcluster or a recent major merger related to the cluster's radio relics. The morphology, temperature, and dynamics of the potential subcluster will be assessed. Further evidence for substructure and shocks across the cluster will also be investigated using surface brightness and temperature maps, as well as any IC emission from the radio relics.

Proposal Number: 10800857

Title: Deciphering Cluster Observables: Tracing the Baryons in Clusters of Galaxies

PI Name: Amalia Hicks

Understanding relationships between observable baryons in galaxy clusters and their underlying dark matter distributions is a crucial goal, particularly for using clusters as cosmological probes. Recent work indicates massive, low-Lx clusters exist at all redshifts, in conflict with self-similarity predictions. The only means to quantify this possibility is to observe a sample of clusters that have been chosen with no regard to their X-ray properties. We propose ACIS-S observations of 11 clusters at 0.15 < z < 0.45 chosen from the RCS cluster survey, for which robust velocity dispersions and/or initial X-ray fluxes are measured. These observations will allow us to measure cluster temperatures and masses, to rigorously assess the baryon content in an unbiased sample of massive clusters.

Proposal Number: 10800906

Title: Abell 2199: AGN outbursts and merger

PI Name: Stephen Murray

Abell 2199 is one of a sample of galaxy clusters with short central cooling times, chosen for a study of the cycle and impacts on clusters of outbursts from active galactic nuclei (AGNs). It shows the hallmarks of an outburst from the AGN at its center and also many signs of a recent minor merger. Furthermore, its central region is one of the brightest at X-ray wavelengths, making it an excellent place to take advantage of the high resolution of Chandra for the study these phenomena. We propose to make a 120 ksec ACIS-I observation of Abell 2199, which will enable a decisive interpretation of the complex structure within it.

Proposal Number: 10800925

Title: Calibration Observation of the Coma Cluster

PI Name: CXC Calibration

This observation will be used to further the cross-calibration efforts of XMM-Newton and Chandra

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