Chandra Large and Very Large Projects

Proposal Number: 11700510

Title: The environmental and epoch dependence of radio-loud AGN feedback

PI Name: Judith Croston

Feedback from radio-loud AGN outbursts is now thought to be an important ingredient in galaxy formation models, potentially solving the `cooling flow' problem in cluster centres and helping to resolve long-standing problems in reconciling CDM models with observed properties of groups and clusters. Now that the role of radio-loud AGN feedback is established, the next step is to understand the relationship between radio-loud AGN energy input, environment and epoch, which appears complex and is currently poorly understood. This Chandra Large Project aims to address this question by characterizing the environments of a unique sample of radio galaxies spanning three orders of magnitude in radio luminosity at a single, cosmologically interesting redshift.

Proposal Number: 07701072

Title: High-resolution spectroscopy of 'binary' AGN in the colliding galaxies of NGC 6240

PI Name: Claude Canizares

We propose to measure the kinematics of the AGNs inside the two colliding spiral galaxies in NGC 6240, by conducting an emission line analysis with the High Energy Transmission Grating Spectrometer (HETGS). Measuring the black hole kinematics will provide new constraints for models of galactic mergers with AGNs, which in turn are important to understand the link between the growth of supermassive black holes and their host galaxies. We can also extract HETGS spectra of the interface between the AGNs and the starburst region, in order to determine whether or not the predicted quenching of the starburst has started occurring near the AGNs.

Proposal Number: 02700294

Title: DETERMINING THE NATURE OF THE VARIABLE ABSORPTION IN NGC 3783 WITH CHANDRA/HST

PI Name: Ian George

We propose 5 Chandra/HETG observations of NGC 3783, each simultaneous with HST/STIS observations already approved. The observations will allow the accurate determination of the variable continuum, absorption & emission line properties known to exist in this Seyfert, and constitute the most comprehensive study possible of the nature, origin and evolution of the X-ray & UV absorbers in an AGN. Such absorbers constitute a major component of the circumnuclear gas in AGN, and only the HETG has the resolution to make these measurements. It is vital to perform such a detailed study early in the mission to facilitate the correct interpretation of the Chandra & XMM observations of this and other AGN. We also ask the TAC to approve a restructuring of Chandra time already awarded to this study.

Proposal Number: 03700413

Title: AN IN-DEPTH STUDY OF THE X-RAY SOURCE POPULATION AND HOT ISM OF THE ANTENNAE GALAXIES

PI Name: Giuseppina Fabbiano

We propose a deep 375~ks observation of the prototypical merger galaxies NGC~4038/39 (``The Antennae''), divided into 5 time segments. Together with the archival data, we will obtain a deep 450ks ACIS-S exposure and time monitoring over 3 yrs. The unique significance of the Antennae for our understanding of mergers and the extraordinary characteristics of the X-ray emission of this system, make this study essential for probing a wide range of fundamental questions on the properties and evolution of XRBs, the range of black hole masses implied by the rich ULX population, the properties of the multiphase ISM, and the evolution of galaxy mergers, that cannot be addressed by looking at more normal galaxies.

Proposal Number: 03700438

Title: RESOLVING THE WARM ABSORBER IN NGC 5548

PI Name: Jelle Kaastra

We propose to map the ionization and velocity structure of the X-ray and UV absorbers in NGC 5548 with the LETGS and HETGS of Chandra and STIS/HST. NGC 5548 is an important target for this kind of study because 1) it shows multiple kinematic components in the UV characterized by a range in ionization parameter and effective column, 2) it shows evidence for multiple kinematic and ionization components in previous Chandra X-ray spectra, and 3) it has a low Galactic column, which permits coverage of spectral lines out to 80 Angstrom with the LETGS. These data yield the ionization parameter and column density of the absorption-line regions as a function of radial velocity, and constrain the elemental abundances and shape of the unobserved EUV continuum.

Proposal Number: 05700535

Title: A Chandra HETGS & HST view of the Warm and Lukewarm absorbers in IRAS 13349+2438

PI Name: Julia Lee

We propose 300~ks Chandra HETGS simultaneous with 4 HST orbits primarily to study the warm absorber environment (chemical compositions, velocities, absorbing column) of the archetypal infrared quasar IRAS 13349+2438. We will look for associations between the X-ray and UV absorbers, and study the properties of dust extinction in this source. Inner shell excitation lines from low ionization ions (previously only probed in the UV) will be compared with HST measurements. We will resolve many of the individual lines of the UTA to put ionization limits on a possible `lukewarm' absorber. The HST spectrum will give us a first view of Ly-alpha and Si IV in this source at shorter wavelengths.

Proposal Number: 04700532

Title: CONNECTING THE X-RAY AND UV IONIZED ABSORBERS IN MRK 279

PI Name: Jelle Kaastra

We propose a deep X-ray/UV spectroscopy campaign on the bright Seyfert 1 galaxy Mrk 279, using Chandra LETGS, HST/STIS, and FUSE. Our main scientific goal is to study the AGN outflow seen as an ionized absorber in this galaxy, focusing on the crucial connection between the X-ray and UV manifestations of the outflows. We will map the ionization and velocity structure, measure the elemental abundances and then determine the mass and kinetic luminosity flux of the outflow - all stepping stones for studying the importance of outflows in the evolution of AGN and their host galaxies. In addition we will use the LETGS data to determine the existence of relativistic CNO emission lines in the spectrum.

Proposal Number: 02700728

Title: FINDING THE BARYONS IN THE LOW REDSHIFT UNIVERSE.

PI Name: Smita Mathur

Recent estimates of the primordial deuterium abundance, combined with the theory of big bang nucleosynthesis (BBN), imply a baryon density parameter $\Omega_b \approx 0.04 h_{70}^{-2}$. The main reservoir of low redshift baryons is still ``missing''. All the observed stellar and gaseous components add up to only $\Omega_b \approx 0.004h_{70}^{-1}$, a factor of ten below the BBN abundance. Hydrodynamic cosmological simulations predict that a large fraction of the low redshift baryons should reside in a hot diffuse intergalactic medium (IGM). We propose to exploit the excellent spectral resolution of Chandra gratings to probe the low redshift IGM with sensitive X-ray spectroscopy. We expect to detect the main reservoir of low redshift baryons with observations of OVII absorption lines.

Proposal Number: 08700916

Title: The Definitive Chandra Observations of NGC 4258

PI Name: Michael Nowak

We propose a 320 ksec HETG observation of NGC 4258. This will yield a high S/N nuclear spectra that is uncontaminated by extended emission or pileup. We will measure the fluorescent Kalpha line strength and width, search for low energy emission lines as expected in some ADAF models, and accurately measure the absorbing column. The latter may be probing the warped disk structure. We will search for nuclear flaring, as observed in Sgr A*. The S/N for observations of the `anomalous arms' will be increased over previous observations. The binary population will be surveyed down to an implied isotropic luminosity of 10^36 erg/s. Our observation will be coordinated with the VLA, to further test the "fundamental plane" of black hole radio/X-ray activity.

Proposal Number: 11700019

Title: A Deep Chandra HETG View of Outflowing Warm Absorbers and Relativistically Blurred Emission in ESO 323-G077

PI Name: Claude Canizares

We propose a 300-ks Chandra HETG observation of ESO 323-G077, a remarkable Seyfert galaxy that shows evidence of two highly ionized warm absorbers and a relativistically broadened Fe Ka emission line (Jimenez-Bailon et al. 2008). We will use the high energy resolution of the HETG to provide the first strong constraints on the nature of the absorbers, and test the hypothesis that they form part of a two-phase outflow from the AGN. We will also this detailed parametrization of the underlying X-ray continuum and circumnuclear absorption to determine if the Fe Ka line is relativistically blurred. Finally, we will use the zero-order HETG image to explore the relationship between any spatially extended X-ray emission and the known [OIII] emission that forms the narrow-line region.

Proposal Number: 08700551

Title: The Chandra-RBGS Survey of a Complete Sample of Luminous Infrared Galaxies

PI Name: David Sanders

We propose a Chandra-ACIS survey of a complete sample of Luminous Infrared Galaxies (LIRGs) with Lir >10^11.5, from the IRAS Revised Bright Galaxy Sample (RBGS). All of these objects are interacting/merging gas-rich spirals. Our new observations will provide a uniform and complete census of AGN and X-ray luminous starbursts in the nearest and brightest LIRGs, and will complement approved Spitzer-IRAC+MIPS, and HST-ACS imaging of the same sample. The results will be used to address the following key questions: are binary AGN a common feature of these LIRGs, and if so, when and at what level is the AGN activity triggered in each nucleus ? and can the fueling and growth of massive black holes be correlated in time with the merger phase ?

Proposal Number: 08700512

Title: Jets, Bubbles, Binaries, and Hot Gas: A Deep Observation of Centaurus A

PI Name: Ralph Kraft

We propose to observe Centaurus A, the nearest radio galaxy and the nearest massive early-type galaxy, for 1.2 Ms. We will probe the particle acceleration processes of the jet to an unprecedented sensitivity, by measuring its spectrum and morphology on the scale of radiative energy losses. We also will measure the proper motions and velocity shear of X-ray knots. We will measure the temperature and density structure of the shock around the SW radio lobe to study the hydrodynamics of the lobe/ISM interaction to a level previously seen only in Galactic SNRs. We will detect hundreds of X-ray binaries, probe the GC/LMXB link, and investigate their temporal properties. Finally, we will measure the thermodynamic paramters of the gas and the elemental abundance throughout the ISM.

Proposal Number: 10700504

Title: The multi-faceted X-ray activity of low-redshift active galaxies

PI Name: Mark Birkinshaw

We propose ACIS-I observations of Chandra-unobserved low-redshift 3CRR active galaxies and their environments. The data will complete Chandra observations of 3CRR at z < 0.1, making the sample useful for statistical studies. Only Chandra can resolve the multiple components of these sources, as is needed for an improved understanding of source physics and gas heating. The imaging and spectroscopy of cores, jets, hot spots, and atmospheres will be of permanent legacy value. We will use the data to investigate particle acceleration, interactions between radio plasma and the ISM and IGM, the emission mechanisms of hot spots, and AGN fueling. Comparison with our complete Spitzer coverage and HST images will aid interpretation. The dataset will be made public immediately.

Proposal Number: 11700501

Title: The Size of Quasar Non-Thermal/X-ray Emission Regions

PI Name: Christopher Kochanek

We will use microlensing, where the stars in a lens galaxy magnify the accretion disk of a gravitationally lensed quasar, to measure the sizes of the X-ray emission regions of 7 gravitationally lensed quasars with well-sampled optical light curves and accretion disk size measurements. We will use these to determine the scaling of the non-thermal emission regions with black hole mass. For two ``active'' systems, RXJ1131-1231 and Q2237+0305, we will use longer observations in order to measure the X-ray energy dependence of the size. We have HST time to monitor the 6 with UV flux to probe thermal emission from near the inner edge of the disk. These observations can only be done with Chandra because future X-ray observatories will lack the necessary angular resolution.

Proposal Number: 11700858

Title: Jet-ISM Interactions in a Restarting Radio Galaxy 4C 29.30

PI Name: Aneta Siemiginowska

We propose to study interactions between radio plasma and ISM with a deep 300ksec Chandra ACIS-S observation of a low redshift radio galaxy, 4C 29.30 where the complexity of such interactions is uniquely displayed allowing a direct mapping of the initial stage of the radio source growth. The high resolution Chandra image will match the resolution of optical and radio structures observed in this source. The X-ray morphology will provide the critical information needed for studying physical conditions and understanding the impact of the evolving radio source onto the host galaxy environment. Our target presents a great laboratory to study the physical mechanisms of AGN feedback, and so provide strong constraints on models of galaxy evolution.

Proposal Number: 10700584

Title: Deconstructing AGN X-ray Spectra - Time for a Paradigm Shift?

PI Name: Tracey Turner

We aim to detect and measure the ionization state and outflow velocities in the well-studied low-BH-mass AGN NGC 4051. We have been granted a 340 ks Suzaku observation to study continuum and low-resolution line spectral variability; HETG spectroscopy complements this by isolating narrow absorption lines arising from key zones of gas, allowing us to measure ionization, column and outflow velocities of the multiple ionized zones. A moderately ionized zone in particular can mimic the appearance of a broad Fe emission line but can be revealed by 6.5 keV Fe Kalpha absorption, for which there is already tentative evidence. A 320 ks HETG exposure will provide powerful diagnostic signatures across a wide range of ionisation. We also request HST time for tie-in UV spectroscopy.

Proposal Number: 07400810

Title: CHAZSS: The Chandra HETGS Atoll/Z Spectroscopic Survey

PI Name: Jon Miller

High-res. X-ray spectroscopy of accretion-powered sources in the Chandra era has focused on black holes. Neutron stars with low magnetic fields - "Z" and "atoll" binaries - have largely been ignored and/or poorly observed at high resolution. We propose a survey of 6 "Z" and "atoll" neutron star binaries. In a total of only 300 ksec, we can observe each of the 6 sources in our sample twice, obtaining consistent, robust, and constraining spectra free from photon pile-up. High-res. spectroscopy will break degeneracies in X-ray timing-based models for the accretion flows in these systems, and provide new insights into both the origin of the "kHz" QPOs seen in these sources and the nature of the "Z" and "atoll" tracks they trace in color-color diagrams.

Proposal Number: 05400594

Title: High Resolution Photospheric Spectroscopy of the Neutron Star in EXO0748-676

PI Name: FREDERIK PAERELS

Recently, we discovered narrow absorption features in the spectrum of 28 X-ray bursts from the neutron star in the LMXB EXO0748-676, whose properties point to a photospheric origin. The transition wavelengths are consistent with the n=2-3 lines in H- and He-like Fe, exhibiting a gravitational redshift of z=0.35. The measured line strengths indicate that the lines are significantly broadened by the Stark effect, and this will ultimately provide an opportunity to determine both the mass and the radius of this neutron star. Here we propose a very deep spectroscopic observation with Chandra HETGS, to detect the Fe Lyman spectrum and obtain crucial independent spectroscopic confirmation for the Balmer line identification, and to measure the spin period of the neutron star.

Proposal Number: 10400827

Title: The cooling neutron star in the super-Eddington accretor XTE J1701-462

PI Name: Jeroen Homan

Observing the cooling of neutron stars that are reheated by accretion provides new insights into neutron star structure. A detailed and efficient study of this cooling requires the use of Chandra. Here we propose to continue our ongoing monitoring campaign of the neutron star binary XTE J1701-462, a unique system that accreted at super- and near Eddington luminosities for more than 1.5 years before recently returning to quiescence. Our goal is to study the cooling of the surprisingly hot neutron star and also the evolution of the enigmatic non-thermal spectral component in unprecedented detail. Our ongoing strategy of frequent observations (every ~2.5 months) is necessary to test the most recent cooling models. We therefore request five ACIS-S observations for a total of 323 ks.

Proposal Number: 10400425

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. We propose to search for such features in bursts from sources uniquely known to exhibit frequent radius-expansion bursts. These observations will result in detection of up to 30 thermonuclear bursts, also providing a high signal-to-noise low-flux state spectrum, as well as allowing a detailed comparison of recurrence time and energetics with numerical ignition models. Detection of discrete features from the burst spectra may lead to highly-sought constraints on the compactness and hence the neutron-star equation of state.

Proposal Number: 03400837

Title: COMPLETE COMPACT OBJECT AND BINARY SURVEY OF 47TUC

PI Name: Jonathan Grindlay

Our cycle 1 observation of 47Tuc has shown its promise as the ultimate laboratory for study of the production and evolution of compact binaries and compact objects in globular clusters. We propose a deep (4 x 75ksec) ACIS-S observation to measure the complete populations of millisecond pulsars (MSPs) and cataclysmic variables (CVs) by their variability and spectra and to constrain the main sequence binary population. Coordinated HST (ACS) data would provide unique identifications of CVs and many MSPs and allow the full population of quiescent low mass x-ray binaries to be distinguished from CVs. This dataset would provide fundamental constraints for the origins of neutron stars, millisecond pulsars, magnetic white dwarfs and compact binaries in globular clusters.

Proposal Number: 07400594

Title: The lowest-luminosity quiescent neutron star transient: implications for strong field gravity and the neutron star EoS

PI Name: Peter Jonker

We propose to obtain a 300 ksec ACIS-S observation of the quiescent neutron star (NS) SXT 1H1905+000. Because of a non-detection during a previous 25 ksec Chandra ACIS-S observation, the NS quiescent luminosity is the lowest of all NS SXTs. It also has a low N_H, a well-known source distance, and an accurately known source position. These observations will eliminate the gap in the derived quiescent luminosities between NS and BH SXTs which is used as being evidence for a BH event horizon. Furthermore, this extremely low NS luminosity allows us to derive that 1H1905+000 harbors a cold, massive NS ruling out all equations of state (EoSs) except the stiffest EoSs for NSs with a nucleonic core. Constraining the NS EoS is one of the ultimate goals of NS studies.

Proposal Number: 06800102

Title: A CHANDRA TREASURY OBSERVATION OF THE BEST EXAMPLE OF A CLUSTER COLD FRONT

PI Name: Alexey Vikhlinin

We propose a 450 ksec observation of A3667, the best example of a cluster cold front. A deep image of the best cold front by the highest angular resolution X-ray telescope will push the study of the physics of the intracluster medium to the limit. Our main goals are 1) to observe the turbulence in the intracluster medium by direct imaging of any perturbations of the front surface; 2) to study transport processes in the ICM using the gas density and temperature profiles across the front with a spatial resolution of 1/5 of the Coulomb mean free path; 3) to characterize the magnetic field structure by mapping the onset of the Kelvin-Helmholtz instability. The proposed deep Chandra image of A3667 will be one of the treasury images of the X-ray astronomy.

Proposal Number: 03800272

Title: MACS: THE X-RAY PROPERTIES OF THE MOST MASSIVE GALAXY CLUSTERS AT Z>0.3

PI Name: Harald Ebeling

We propose ACIS-I and HST observations of 30 distant and very X-ray luminous clusters (z>0.3, Lx>1e45) detected in the MAssive Cluster Survey (MACS). 22 of these 30 are new discoveries. Our targets are the high-z counterparts of the best-studied local systems and, combined with 4 others scheduled for observation, form a statistical sample >10 times larger than any previous one in this redshift and luminosity range. Chandra's unique capabilities will allow us to obtain spatially resolved gas temperature and density maps to constrain both the cosmological and physical parameters governing the evolution of the most massive clusters at z<0.5. The proposed observations are complemented by extensive groundbased follow-up studies of weak gravitational lensing, galaxy dynamics and the SZ effect.

Proposal Number: 08800952

Title: A Complete Baryon Census in a Nearby Galaxy Group

PI Name: John Mulchaey

We propose an ACIS-I mosaic of the NGC2563 group to study the X-ray properties of the group galaxies out to the virial radius of the system. The proposed observations will provide important observational constraints on the mechanisms that drive galaxy evolution in groups by allowing us to study how the properties of galaxies vary with distance from the group center, IGM and galaxy density. The Chandra data will allow us to study the hot ISM halos of individual galaxies as well as the more extended intragroup medium component, which combined with our existing optical and HI data will provide a complete census of all of the major baryonic components in the group.

Proposal Number: 07800432

Title: The Cosmological Formation of Galaxy Groups

PI Name: DAVID BUOTE

One of the strongest, untested cosmological predictions is the scatter of the concentrations of dark matter halos on the group scale. To quantify this scatter of concentrations requires well-defined samples. We propose a novel systematic study of the core properties of 15 groups representing a complete, X-ray flux-limited sample. In addition to dark matter properties, we will address: (1) entropy and non-gravitational heating, (2) central iron abundances and stellar enrichment, (3) AGN heating and the cooling flow paradox, and (4) the formation of central galaxies. The implications of these measurements for cosmology, supernovae history, star formation and AGN heating will be assessed with numerical simulations. We request observations of 10 unobserved groups in our sample

Proposal Number: 05800170

Title: A Megasecond Image of the Core of the Perseus Cluster

PI Name: Andrew Fabian

We propose a further 800 ks observation of the Perseus cluster, A426, the X-ray brightest cluster of galaxies in the sky. By combining this observation with our current data we will obtain a 1 Ms "ultimate image" of the cluster. Our main goal is to quantify the ripples due to the propagating sound waves seen in our 200 ks image. A detailed understanding of the mechanisms in the nearby Perseus cluster will unable us to fully understand the solution to the "cooling flow problem". The Perseus cluster is the only extragalactic source with such a high ACIS-S surface brightness over many sq arcmin. We propose that it should be observed as deeply as possible with Chandra and before any further degradation takes place in the performance of the detectors or spacecraft.

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: 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: 02800845

Title: A COMPLETE X-RAY CLUSTER SAMPLE AT Z > 0.8

PI Name: Spencer Stanford

We propose to observe three X-ray selected clusters of galaxies from the RDCS, one at z = 1.1 and two at z ~ 0.8. In conjunction with other data already being obtained by Chandra and XMM, we would then have luminosity and temperature measurements for a complete sample of 8 clusters at z > 0.8. We will produce the first temperature function at these high redshifts. Using Chandra's high angular resolution, we can minimize the contamination from point sources, a serious problem at faint flux limits, as well as study the spatial properties of the intra-cluster medium. With this combination of temperatures, luminosities, and spatial profiles, we will both probe the cluster mass function of the universe at high redshift and study the thermal history of the intra-cluster medium.

Proposal Number: 06800101

Title: DARK ENERGY WITH X-RAY CLUSTERS: CHANDRA OBSERVATIONS OF 41 HIGH-REDSHIFT CLUSTERS FROM THE 400 deg^2 ROSAT PSPC SURVEY

PI Name: Alexey Vikhlinin

We propose Chandra observations to measure temperature and gas mass in a sample of 41 high-z galaxy clusters from our 400 deg^2 ROSAT survey. This sample is comparable in number to all clusters in the local Universe (z<0.1) above a similar limiting mass, and covers a factor of 3 larger volume at z=0.4-1. Chandra observations will provide the total mass function estimates at =0.4, 0.5, and 0.65, which can be directly compared with the local measurements at =0.05. These data will provide a measurement of the dark energy equation of state via the cluster evolution test which is completely independent from SN Ia and CMB and has different degeneracies. Some targets in this proposal are in common with the HRC GTO proposal 06900018. These programs are not in conflict.

Proposal Number: 04800280

Title: SURVEYING THE FORNAX CLUSTER OF GALAXIES

PI Name: Caleb Scharf

Low luminosity X-ray clusters of galaxies are the dominant reservoirs of bound matter in the Universe. At a distance of 20 Mpc, the Fornax cluster has an immense collection of the highest quality multi-wavelength data, making it an exceptional laboratory for studying the astrophysics of these systems. We propose surveying an inner region of Fornax with Chandra's unprecedented combination of spatial and spectral resolution to produce a keystone dataset with a long-term legacy. We will investigate the interactions of cluster galaxies with the ICM, their populations of globular clusters, search for emission from dwarf galaxies, ultra-compact systems, and intra-cluster planetary nebulae, and compare the ICM metal contents with the detailed history of stellar populations in Fornax.

Proposal Number: 09800310

Title: Probing Dark Energy with Relaxed Galaxy Clusters

PI Name: Steven Allen

We seek to constrain dark energy using studies of the apparent evolution of the X-ray gas mass fraction in the most X-ray luminous, dynamically relaxed galaxy clusters. The proposed observations will improve the detection of the effects of dark energy from the X-ray data alone to > 5 sigma. More importantly, they will allow us to measure the level of intrinsic (systematic) scatter in distance measurements from this technique and establish whether this is smaller than from type Ia supernovae measurements. Used in combination with supernovae and CMB data, the new Chandra observations will allow the most precise search to date for evolution in the dark energy equation of state - our best approach in trying to understand the origin of cosmic acceleration.

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: 04800927

Title: CHANDRA OBSERVATIONS OF DLS SHEAR-SELECTED CLUSTERS

PI Name: John Hughes

We propose Chandra observations of the most massive clusters currently identified from the Deep Lens Survey (DLS). The DLS is a deep multicolor (BVRz') imaging survey of 28 square degree being carried out at the 4-m telescopes of the US National Observatories (KPNO and CTIO). The DLS shear-selected cluster sample makes it possible for the first time to study clusters in a baryon-independent way. We are pursuing detailed investigations of this sample with HST and ground-based Keck spectroscopy. Chandra observations will meet multiple high-impact scientific goals, specifically, testing the ``fair sample'' hypothesis, calibrating the relationships between cluster mass, size, X-ray luminosity and temperature, and studying the evolution of these relationships with look-back time.

Proposal Number: 09800847

Title: BOW SHOCK, ELECTRON-ION EQUILIBRIUM, BREAKUP OF COOL CORE, AND DARK SUBCLUSTER IN ABELL 520

PI Name: Maxim Markevitch

Shock fronts provide a unique tool to study the cluster plasma. Only two have been found, those in 1E0657 and A520. Using a long observation of 1E0657, we have determined, for the first time in any astrophysical plasma, that electron-proton equilibration time is shorter than Coulomb - a tantalizing result but based on one object. A520 gives the only chance to confirm it. Its shock also coincides with an edge of the radio halo, enabling tests of the origin of the intracluster relativistic electrons. A520 also exhibits a remnant of a cool core broken up by merger-induced instabilities, providing data on plasma viscosity. Finally, weak lensing map of A520 reveals an intriguing dark subcluster almost devoid of galaxies. We propose a long observation of this exceptionally interesting cluster.

Proposal Number: 06800613

Title: The History of AGN Activity in M87 and the Interaction of Nuclear Outbursts with the Surrounding Atmosphere

PI Name: William Forman

We propose a 500 ksec ACIS-I observation to study the interaction between energy outbursts from the supermassive black hole (SMBH) in M87 and its surrounding gaseous atmosphere. We will inventory the plasma bubbles inflated by the SMBH, search for weak shocks, study the interaction of relativistic plasma in bubbles with the surrounding hot gas, measure turbulence in the cluster gas, study the microphysics of the interaction between the plasma in the bubbles and the surrounding gas, and estimate the gas viscosity by measuring the width of shock fronts. By determining the energy associated with bubbles and shocks, we can chronicle the mechanical power output of the SMBH. Finally we will study particle acceleration and cooling models by measuring inter-knot spectra along the jet.

Proposal Number: 05800890

Title: THE MOST INTERESTING CLUSTER IN THE UNIVERSE

PI Name: Maxim Markevitch

The galaxy cluster 1E0657-56 is a treasure trove of information on just about every problem in cluster physics. It is the only cluster known to have a shock front with M substantially greater than 1. The proposed 500 ks observation, combined with the existing 90 ks, will allow us to determine whether electrons are heated adiabatically or dissipatively in a shock and whether the electron-ion equilibration is efficient. We will search for an electron temperature precursor to the shock to estimate thermal conductivity. We also will determine the importance of gas turbulence and study the destruction of a cooling flow remnant by ram pressure. Combined with data from other wavelengths, this observation can also shed light on the nature of dark matter and the origin of cluster radio halos.

Proposal Number: 11800102

Title: Extending the Deep Image of the Perseus Cluster: The Outer Bubbles, Filaments and Ripples

PI Name: Andrew Fabian

Our existing 900ks image of the core of the Perseus cluster has revealed a wealth of detail on the bubbles, shocks and ripples caused by the action of the central AGN on the surrounding ICM. Most of the advances are directly due to the high surface brightness of the Perseus cluster (higher than any other cluster) and to the high spatial resolution of Chandra. This resolution is degraded significantly 4 arcmin or more off-axis, meaning that the region studied at the highest resolution is quite small. Here we propose three further exposures totalling 700ks to extend the highest resolution region, covering areas to the N and S of the nucleus where the current data suggest the presence of further intriguing and important structures due to the AGN activity.

Proposal Number: 11800471

Title: Chandra Observations of a Complete Sample of SZE Selected Galaxy Clusters

PI Name: Joseph Mohr

We propose to obtain X-ray observations of a complete sample of 16 SZE selected galaxy clusters from the South Pole Telescope (SPT) survey. The SZE selection produces an approximately mass limited sample (at all redshifts) over the existing 200 deg^2 SPT survey. The Chandra observations provide X-ray mass estimates and morphologies, allowing (1) an initial calibration of the SZE flux-mass relation and (2) early tests of cosmology and the evolution of structure. Our 346ks request leverages 625ks of GTO time in AO10/11; these X-ray data are crucial to developing an understanding of the new window on the universe that SPT has opened and in laying the foundation for future studies using the full SPT survey (~1400deg^2 by 2010).

Proposal Number: 08900073

Title: THE CHANDRA-COSMOS SURVEY

PI Name: Martin Elvis

We propose the Chandra-COSMOS survey which will provide an unprecedented combination of contiguous area, depth and resolution. 36 densely tiled observations will cover the central 0.7 sq.deg. COSMOS field to a uniform 200ksec depth. COSMOS explores the coupled evolution of galaxies, dark matter halos and AGNs (massive black holes) largely free of cosmic variance. COSMOS is a comprehensive survey including: HST, Spitzer, Subaru, VLT, Magellan, VLA, MAMBO, GALEX, & potentially EVLA & ALMA. Chandra resolution & sensitivity enables the study of large scale phenomena: (1) influence of the surrounding environment; (2) interaction between galaxies; (3) influence of groups and clusters: (4) BH growth and census; (5) star formation and stellar populations; (6) feedback from starbursts and AGNs.

Proposal Number: 05900547

Title: The Balance of Power between Starbursts and AGN: a Chandra/SIRTF Survey.

PI Name: Belinda Wilkes

We propose a moderate-depth (70 ksec), 0.6 sq.deg. Chandra survey, the deepest/largest CONTIGUOUS area to date, in the Lockman Field of the SIRTF/SWIRE Legacy Survey coincident with a completed, ultra-deep VLA survey with deep optical and near-IR imaging in-hand. SWIRE, the largest SIRTF program, will detect >500 000 dusty galaxies to z > 2.5 in 7 fields covering 65 sq.degs. The prime science goal is to study the structure, evolution and environments of AGN, starbursts and ellipsoids over the SAME SPATIAL VOLUME out to z > 2.5. Key to this study is an X-ray survey deep enough to distinguish starbursts and AGN, including the significant, highly obscured (log Nh>22) subset. Chandra will secure X-ray identification and fluxes for ~550 (0.6 sq deg) of the field's ~7000 SWIRE sources.

Proposal Number: 09900660

Title: The Evolution of Faint AGN at High Redshift

PI Name: Kirpal Nandra

We propose a very deep (total 800ks/field) Chandra survey of 0.25 deg2 covering 3 contiguous fields in the Extended Groth Strip, which have exceptional multiwaveband coverage obtained by the AEGIS project. These data, in combination with the CDF North and South, will provide a definitive measurement of the evolution of faint, X-ray selected AGN from z=3-4, where the optical number counts start to drop dramatically. In combination with ultradeep Spitzer data in the same region, this survey will also provide a crucial step forward towards a more complete census of AGN activity and the importance of Compton thick AGN at high z, with associated implications for the total accretion budget of the universe.

Proposal Number: 07900865

Title: Searching for WHIM in Large-Scale Structures

PI Name: Luca Zappacosta

Simulations and observations indicate that galaxy overdensities are good tracers of the dark matter large-scale structures and therefore of the diffuse warm-hot phase (WHIM) that should be associated with them. The WHIM in these large-scale structures should have large column densities, and therefore should be much easier to detect than the low column density WHIM which has been targeted so far. However, this efficient method of investigating WHIM has yet to be exploited. We have identified 5 bright blazars just in the background of known large-scale structures. We propose to probe and study the WHIM in these structures by identifying the associated absorption lines in the spectrum of these AGNs during their outburst phases, through TOO observations for a total of 300ks with HRC-S/LETG.

Proposal Number: 02900378

Title: AN ULTRADEEP SURVEY IN THE CHANDRA DEEP FIELD SOUTH

PI Name: RICCARDO GIACCONI

We propose to exploit the unique combination of angular resolution, sensitivity and field-of-view of the Chandra ACIS imager to perform the deepest X-ray survey ever in the well-studied "Chandra Deep Field South" (CDFS). With a total integration time of 1.5 Msec (request for this AO: 1 Msec) we reach a 0.5-2 keV flux limit of 2E-17 cgs. We aim to detect >500 sources, i.e. AGN to z=10, clusters to z=3 and starburst galaxies to z~1. Simulations based on the existing 130 ksec observation in the CDFS and realistic source counts and correlation function models show, that Chandra exposures will not be background or confusion limited up to 3Msec. We propose to make the Chandra data public immediately.

Proposal Number: 05900888

Title: X-Raying the Intergalactic Medium with Blazars in Outburst

PI Name: Fabrizio Nicastro

We propose to extend our highly succesful Chandra-AO4 TOO program to the 5th Chandra cycle, to observe up to 2 blazars in exceptionally high states with the Chandra HRCS-LETG (hereinafter HLETG) for a total exposure time of 350 ks. We shall study the ``warm'', low-redshift, phase of the intergalactic medium, where most of the baryonic matter of the local (z < 1-2) Universe is believed to hide.

Proposal Number: 06900444

Title: Deep Chandra Imaging of the Extended Groth Strip: The Co-evolution of Black Holes and Galaxies

PI Name: Kirpal Nandra

The Extended Groth Strip (EGS) is a half square degree region that has been targeted intensively for galaxy evolution studies. A remarkable array of ultra-deep data have been or will be accumulated, to include radio, near/mid/far IR, optical and UV data of depth comparable to or better than any part of the sky. It is also the subject of the massive DEEP2 redshift survey, giving high quality Keck spectra for 16-17,000 galaxies. The clear gap in the coverage of the EGS is in the X-ray, and we therefore propose to augment the single deep Chandra pointing with 7 more, to image the whole strip. Our goal is to study the co-evolution of galaxies and black holes, by examining in detail the astrophysics of AGN activity, and its relationship to the host galaxy and surrounding large scale structure.

Proposal Number: 04900340

Title: A CHANDRA WIDE-FIELD SURVEY TO MAP THE COSMIC WEB AND INVESTIGATE THE EVOLUTION OF NUCLEAR ACCRETION

PI Name: Christine Jones

We propose a wide-field X-ray imaging survey with deep and shallow components in order to map the structure and evolution of the Universe to redshift unity, and to probe the nature, environment and evolutionary history of AGN. The observations will cover the Bootes field of the NOAO Deep Wide-Field Survey, that is unique in its wide-field coverage and availability of deep multiwavelength imaging (including VLA and SIRTF) and optical spectroscopy. The Chandra survey is designed to sample volumes appropriate for statistical investigations of cluster environments, the space density of groups, biases in the optical and X-ray selection of groups and clusters, and AGN phenomena in relation to galaxy host properties and their evolution.

Proposal Number: 03900164

Title: THE CHANDRA SURVEY OF THE HUBBLE DEEP FIELD NORTH AREA: A PUBLIC RESOURCE FOR THE PRESENT AND FUTURE OF X-RAY ASTRONOMY

PI Name: William Brandt

We propose to extend the Chandra deep survey of the HDF-N and its vicinity. The ultimate goal is to obtain 5 Ms of coverage over the next 5 years; currently we have 1 Ms coverage. Here we propose two public 500 ks observations. This project will fulfill one of Chandra's central design goals and will be a long-lasting legacy of Chandra, laying the groundwork for the next generation of X-ray observatories. We should remain nearly photon limited for point-sources near the aim point. We will study obscured and high-redshift AGN, starbursts, normal galaxies, clusters, groups, and diffuse X-ray emission. The HDF-N field is the ideal region for multiwavelength follow-up studies due to the enormous database already in place. Our ACIS team expertise will be extensively utilized.

Proposal Number: 08900784

Title: The Duty Cycle of Supermassive Black Holes: X-raying Virgo

PI Name: Tommaso Treu

Nuclear accretion on to super-massive black holes (SMBHs) plays a key role in the evolution of their host galaxies, as inferred from the ubiquity of SMBHs and the correlations between BH mass, and host mass and velocity dispersion. A fundamental unadressed issue is the actual distribution of accretion rates; we propose snapshot observations of an unbiased sample of 84 early-type galaxies in the Virgo cluster. Together with joint Spitzer 24 um observations, and publicly available HST-ACS and UV data, this survey will probe low-level nuclear activity over four orders of magnitude in black hole mass, thereby delivering the first unbiased census of the duty cycle of local SMBHs.

Proposal Number: 02900196

Title: THE CHANDRA DEEP SURVEY OF THE HUBBLE DEEP FIELD NORTH (HDF-N) AREA

PI Name: William Brandt

We propose to extend the Chandra X-ray survey of the HDF-N and its vicinity with a 475 ks exposure; this will give 1 Ms of total coverage on this field and will fulfill one of Chandra's central design goals. We should remain photon limited to 1 Ms and will probe the X-ray Universe more than four times deeper than any observation to date. We should resolve essentially all of the X-ray background from 0.5-8 keV and will study obscured and high-redshift active galaxies, advection dominated sources, starbursts, X-ray binaries, clusters and groups, and diffuse X-ray emission. The HDF-N field is an ideal one for multiwavelength follow-up studies due to the enormous database already in place. All data are to be placed in the public archive immediately and we will request no GO science funding.

Proposal Number: 05900218

Title: The Extended Chandra Deep Field-South Survey: A Public Chandra Legacy

PI Name: William Brandt

We propose to extend the 1 Ms Chandra Deep Field-South (CDF-S) survey with six public 330 ks flanking observations: the Extended CDF-S (E-CDF-S). Using these, we will study the detailed cosmic history of accretion onto supermassive black holes, the role of moderate-luminosity AGN at high redshift, AGN clustering, and X-ray groups and low-luminosity clusters. The proposed observations are optimized to fill the X-ray luminosity/redshift plane at z > 1.5 where the AGN source statistics are still limited. Follow-up studies will exploit the superb E-CDF-S multiwavelength coverage including VLT/Keck spectroscopy (6000+ VLT redshifts), HST imaging (GEMS, GOODS, ACS Ultradeep Field; 734 HST orbits), intensive ground-based imaging, and scheduled SIRTF observations.

Proposal Number: 10900836

Title: A Benchmark Observation of the Warm-Hot Intergalactic Medium

PI Name: Taotao Fang

Searching for the ``Missing baryons'', in the form of the warm-hot intergalactic medium (WHIM), is a fundamental challenge faced by the current theory of structure formation. Cosmological simulations predict that majority of the WHIM can be probed in X-ray only, yet the reported detections are often in question due to statistical and systematical issues. Based on the tentative evidence in our joint XMM-Chandra ToO observations of H 2356-309, we propose a deep, non-ToO Chandra observation to definitively detect the WHIM absorption line with a measured column density expected from theory. A null detection would place an upper limit which cannot be explained by current cosmological simulations, and put future pursuit of the WHIM with current generation of X-ray telescopes in question.

Proposal Number: 11900514

Title: COMBH: Chandra Observations of M-sigma Black Holes

PI Name: Kayhan Gultekin

Galaxies with dynamically-measured central BH masses allow us to understand BH accretion, jets, and interactions between BHs and host galaxies with a clarity not possible in random surveys. By measuring true Eddington fractions, we can calculate the energy in radiation vs mechanical jet energy and the efficacy of BHs in heating nuclear regions and affecting star formation. Remarkably, 1/3 of SMBHs making up the M-sigma relation have been poorly observed or totally unobserved with Chandra. We propose a survey of 15 M-sigma galaxies to complete the sample of reliable M-sigma SMBHs. For each galaxy we propose to obtain 30-60 ks exposures and an hour-long VLA observation. This survey will test and extend the fundamental plane of BH activity and facilitate studies of the origin of M-sigma.

Proposal Number: 04901014

Title: A CHANDRA WIDE-FIELD SURVEY TO MAP THE COSMIC WEB AND INVESTIGATE THE EVOLUTION OF NUCLEAR ACCRETION

PI Name: Christine Jones

We propose a wide-field X-ray imaging survey with deep and shallow components in order to map the structure and evolution of the Universe to redshift unity, and to probe the nature, environment and evolutionary history of AGN. The observations will cover the Bootes field of the NOAO Deep Wide-Field Survey, that is unique in its wide-field coverage and availability of deep multi- wavelength imaging (including VLA and SIRTF) and optical spectroscopy. The Chandra survey is designed to sample volumes appropriate for statistical investigations of cluster environments, the space density of groups, biases in the optical and X-ray selection of groups and clusters, and AGN phenomena in relation to galaxy host properties and their evolution.

Proposal Number: 06900144

Title: Continuing X-Raying the Intergalactic Medium with Blazars in Outburst: Deeper in Redshift and Wider in Area.

PI Name: Fabrizio Nicastro

We propose to extend our highly succesful Chandra-AO4 and -AO5 TOO programs to the 6th Chandra cycle, to observe up to 2 blazars in exceptionally high states with the Chandra HRCS-LETG (hereinafter HLETG) for a total exposure time of {\bf 340 ks} (2 orbits). We shall dramatically reduce the uncertainty on the cosmological baryon mass density $\Omega_b$ in the local Universe studying the ``warm'', low-redshift, phase of the intergalactic medium (WHIM), where most of the baryonic matter of the $z \ls 1$ Universe is believed to hide.

Proposal Number: 08900745

Title: The Chandra Deep Proto-cluster Field: Black-Hole Growth and Feedback in Dense Environments

PI Name: David Alexander

Deep X-ray surveys have revolutionized our understanding of the growth of black holes (SMBH). But these surveys only sample low-density regions at high-z due to their limited solid angle. There is no comparably sensitive X-ray census of AGN in high-density regions at high-z. Such environments evolve into the most massive clusters at z=0, regions which exhibit remarkable trends in galaxy properties - which may reflect early interactions between SMBHs and their host galaxies. A survey of a proto-cluster at high-z would provide a unique view of the interplay of the growth of galaxies and their SMBHs. Here we propose a 400ks survey of the best-studied proto-cluster at high-z, to enable the first definitive study of the growth of SMBHs and their host galaxies in a dense, young, environment.

Proposal Number: 07910613

Title: A Legacy Study of Stellar Life Cycles at the Galactic Center

PI Name: Michael Muno

We propose a set of 27 40 ks Chandra observations of the central 300x80 pc of the Galaxy, as part of a multiwavelength project to study stellar life cycles in the region. Our observations will increase the number of accreting compact objects detected there by a factor of 10, to 12,000. This sample will: (1) increase the known number of HMXBs with IR counterparts several-fold, providing stringent tests of population synthesis models, (2) provide spectral and timing data on a new class of faint X-ray transients, (3) identify the sites of recent star formation by detecting their X-ray luminous WR/O stars, (4) identify elusive young pulsars near the Galactic Center, and (5) constrain the physics of particle acceleration in the mysterious radio filaments.

Proposal Number: 06910168

Title: Massive Star Life, Death, and Rebirth in the Perseus Arm

PI Name: Leisa Townsley

This joint Chandra/XMM mosaic of W4/W3/HB3 allows us to chronicle the X-ray output of the entire life cycle of high-mass stars, from their intrinsic and wind-collision emission, through their SN phase, and back to the embedded, protostellar X-rays heralding the next generation of massive star formation. In addition we see the feedback of these massive stars on the interstellar medium in the Perseus Arm: the stellar winds from a massive young cluster (IC 1805) have blown the W4 superbubble and chimney; perhaps an older superbubble is over 100 times brighter in X-rays due to supernovae in its interior (HB3), and the expansion of these bubbles is compressing the W3 molecular cloud and triggering a new generation of stars to form.

Proposal Number: 09910161

Title: The Great Nebula in Carina: Protoplanetary Disks to Starburst Galaxies

PI Name: Leisa Townsley

The Great Nebula in Carina is a superb site to study the violent massive star formation and feedback that typifies giant HII regions and starburst galaxies. We propose to map the Carina star-forming complex with a mosaic of 20 new 60-ks ACIS-I pointings as a testbed for understanding recent and ongoing star formation and to probe its regions of bright diffuse X-ray emission. We will provide a catalog of multiwavelength properties of ~12,000 X-ray-selected stars. We will explore superbubble confinement, shocks, cloud evaporation, mass-loading of winds, ISM enrichment, and HII region energetics. We will also examine Carina as a surrogate environment for our Solar System's formation, where protoplanetary disks are bathed in harsh winds and radiation from nearby massive stars.

Proposal Number: 02910585

Title: CHANDRA SURVEY OF THE GALACTIC RIDGE AROUND THE MILKY WAY CENTER

PI Name: Q. Daniel Wang

We propose an X-ray survey of a 2.4x0.7 square deg field around the Galactic center, using a set of Chandra ACIS pointings. With the unprecedented spatial and spectral resolutions as well as the broad energy coverage, this survey will provide an invaluable database for studying X-ray pulsars, binaries, supernova remnants, and superbubbles as well as many unique features observed in the field. The resultant exquisite X-ray images, complemented by an existing large-scale ROSAT PSPC mapping in soft X-ray, will allow for direct comparison with similar maps in radio and infrared. In particular, the survey will provide an excellent opportunity to determine the origin of the well-known Galactic ridge X-ray emission.

Proposal Number: 09910246

Title: THE ORIGIN OF THE GALACTIC RIDGE X-RAY EMISSION

PI Name: Mikhail Revnivtsev

We propose a very deep (900 ksec) observation of a carefully selected patch of the Galaxy. This observation will provide the most direct and unambiguous answer to the 30-year-old puzzle of the nature of the Galactic "diffuse" X-ray emission. Recent studies comparing the luminosity function of X-ray sources in the Solar neighborhood with the number-flux distributions toward the Galactic Center and plane strongly suggest that the GRXE can be explained by the integrated emission of millions of faint stellar sources - CVs and coronally active stars. The surface density of them is expected to exceed 1 per 60sq.sec in the proposed observation, in sharp contrast to the expectation in the diffuse model. Clearly, Chandra is the only mission in the foreseeable future which can solve this problem.

Proposal Number: 05600587

Title: An Ultra-Deep Study of M101

PI Name: Kip Kuntz

We propose a multi-segmented 1 Ms observation of M101, a near-by face-on spiral in a direction of low Galactic absorption. The observation will detect point sources to L(0.5-2.0 keV)=4x10^35 ergs/s, detect nearly all young to middle-aged SNR, detect and resolve super-bubbles typical of the Milky Way, and provide an unprecedented view of the hot ISM in a spiral galaxy. Coupled with our HST-ACS images, we will be able to measure directly the X-ray output of individual stellar clusters, and better determine the galactic energy budget. The resulting images will bring a wealth of material to a broad range of galactic, stellar, and ISM studies.