Cycle 5 Accepted Archive Proposals

Although the Soft X-Ray Background (SXRB) was measured over the entire sky in the ROSAT All-Sky Survey, many questions remain. A substantial fraction of the SXRB appears to have a very local origin, and it has been suggested that this arises from charge exchange (CX) between the solar wind and neutral gas surrounding the Earth and in the heliosphere. Very recently, strong temporal and spectral evidence in support of this idea has been found. We propose to use existing Chandra data in a definitive search for such CX emission, with the aim of producing reliable models of heliospheric and geocoronal CX emission, and to separate local and truly cosmic contributions to the SXRB.

A major discovery in the study of stellar outer atmospheres is the surprising pattern of abundance anomalies in the coronae of stars. The peculiar abundances, telling us something about the underlying physics of how plasma is heated and sustained on stars, are vital to understanding the radiative loss and energy balance of stellar outer atmospheres, and could provide clues to chemical fractionation processes at work in other areas of astrophysics. The aim of this archival proposal is to establish for the first time a firm and accurate empirical understanding of anomalous coronal abundances as a function of spectral type and activity level using {\it Chandra} high resolution spectra and robust new analysis techniques.

We propose to continue our successful ChaMPlane survey of low luminosity sources in or near the galactic plane. The past year has seen signficant progress in this survey program, with our discovery of a central excess of sources in the galactic bulge and the development of new tools to combine the x-ray and optical surveys. Over the coming year, an additional ~15-20 fields will be analyzed to allow significant source samples. The x-ray and optical archives will be put on line with new web-based tools for easy access.

Proposal Title: Arcsecond resolution and broad energy band investigation of X-ray halos of bright galactic X-ray binaries

X-ray halos around point sources provide a probe for ISM, but they may also distort the spectra of point sources. With low spatial resolutions, previous instruments cannot resolve the core region of the halo. ACIS/Chandra is the best instrument for the halo study, but the observations of bright sources always suffer from severe pile-up. We have developed a new technique to reconstruct the source and halo image from CC-mode or grating data. We propose to apply our new technique to bright X-ray binaries observed with Chandra HETGS, in order to resolve the X-ray halos as close as 1 arcsecond to the point sources then to constrain the dust models, and to derive ``net'' spectra of the point sources, which will yield more reliable physical parameters.

Proposal Title: Identifying Reverse Shock X-Ray Emission in the Cas A Supernova Remnant

We propose a study of archival Chandra images of the Cas A remnant in order to understand the X-ray emission at the precise location of the current reverse shock front in the high-velocity, metal-rich SN debris. We will make use of two ACIS-S images taken in Jan 2000 and Feb 2002. These almost exactly match in time HST observations of the remnant which led to the discovery of the current location of the reverse shock front in several regions of the bright, main emission shell. Our basic research goal is to understand the X-ray properties of these regions, thereby providing context for the X-ray spectral and flux variations that are seen within the remnant between the two epochs in regards to unambiguous reverse shock phenomena.

Proposal Title: X-ray Census of Supermassive Black Holes: II. Archival Investigation

A census of the most secure dynamically measured supermassive black holes (SMBHs) in the local universe is approaching completion. We propose a uniform analysis of archival Chandra data of all previously observed such systems. A companion proposal targets previously unobserved SMBH host galaxies in order to complete the joint sample. Our program sheds light on the nature and evolution of accretion flows around SMBHs, and on the connection to the nuclear and global galaxy environment.

Proposal Title: A Search for Optical Counterparts to Ultraluminous X-ray Sources

Ultraluminous X-ray sources are extranuclear sources with L_X > 10^39 ergs/s found in galaxies. To date their nature is not known and they may represent several different classes of object. The discovery and study of optical (and other bandpass ) counterparts is essential for further understanding of these objects. Often HST or other images are available with coverage of the ULX position but the Chandra astrom etry is not sufficient to unique identify a counterpart. We propose to systematicall y correct the astrometry of Chandra fields with ULXs, with emphasis on fields with H ST coverage. Our results will be published as a catalog in the literature and made a vailable electronically (e.g., via Vizier). We will use our catalog to study the nat ure of ULX counterparts and their environment.

Proposal Title: Using the Chandra Archive To Study Low Mass X-ray Binaries & Globular Cluste rs in Virgo & Non-Virgo Early-Type Galaxies

We will analyze archival Chandra observations of early-type galaxies to dete ct their Low Mass X-ray Binaries (LMXBs). We will determine the luminosities, lumino sity function, spectral properties, X-ray colors, and variability of the LMXBs. Many luminous supersoft sources will be detected. LMXBs are our only direct observation of the massive stars which once existed in E/S0s. About a third of our sample galaxi es will be observed as part of the HST ACS Virgo Survey, which will determine their globular cluster (GC) populations. Previous observations have shown that a high frac tion of LMXBs in E/S0 galaxies are located in GCs. We will compare the properties of the GC and non-GC LMXBs, with the aim to understand the origin of LMXBs, and to con strain the evolution of GCs and E/S0 galaxies.

Proposal Title: An Archival Study of the Fe-K Lines in AGN using the Chandra High Energy Gratings

We propose to carry out a large archival study of the Fe-K lines in AGN obse rved by HETGS. Preliminary results already show that a wide variety of physics will be probed. The data afford the best spectral resolution in the Fe-K band currently a vailable (1860 km/s FWHM at 6.4 keV). Detailed results on 39 individual sources, as well as statistical analyses on the sample of 69 observations will provide a powerfu l resource for both theorists and observers, in all wavebands. The results will also be useful for planning programs and instrumentation for future missions. We will ma ke the final spectra publicly accessible in formats which can be easily used by non- experts.

We propose to carry out a detailed study of the X-ray properties of LINERs. We will use archival data for galaxies hosting LINERs that were observed with Chandr a with long exposure times for unrelated reasons. Our scientific goals are to charac terize the X-ray properties of LINERs and use them to find out the nature of their p ower sources. We have constructed a sample of 12 galaxies that are suitable for our purposes. Analysis of the proposed sample will double the available results for this important class of object, since there only a dozen long Chandra observations speci fically targeting LINERs. Snapshot surveys, although important, are extremely shallo w and cannot detect the faint structures present in most LINERs, which are the key t o understanding their power sources.

Proposal Title: Active Galactic Nuclei in Progenitors of Massive Early-Type Galaxies at z>2

Proposal Number	Subject Category	PI Name	Title
05100310	SOLAR SYSTEM	Bradford Wargelin	Solar Wind Charge Exchange and the Soft X-Ray Background
05200866	NORMAL STARS AND WD	Jeremy Drake	The Chandra Coronal Abundances Project
05300989	WD BINARIES AND CV	Jonathan Grindlay	ChaMPlane Survey Analysis and Data Base
05400392	BH AND NS BINARIES	Yangsen Yao	Arcsecond resolution and broad energy band investigation of X-ray halos of bright galactic X-ray binaries
05500824	SN, SNR AND ISOLATED NS	Robert Fesen	Identifying Reverse Shock X-Ray Emission in the Cas A Supernova Remnant
05600291	NORMAL GALAXIES	Michael Loewenstein	X-ray Census of Supermassive Black Holes: II. Archival Investigation
05600869	NORMAL GALAXIES	Andrew Ptak	A Search for Optical Counterparts to Ultraluminous X-ray Sources
05600879	NORMAL GALAXIES	Gregory Sivakoff	Using the Chandra Archive To Study Low Mass X-ray Binaries & Globular Clusters in Virgo & Non-Virgo Early-Type Galaxies
05700087	ACTIVE GALAXIES AND QUASARS	TAHIR YAQOOB	An Archival Study of the Fe-K Lines in AGN using the Chandra High Energy Gratings
05700131	ACTIVE GALAXIES AND QUASARS	Michael Eracleous	An Archival Study of the X-Ray Properties of LINERs
05700517	ACTIVE GALAXIES AND QUASARS	PIETER VAN DOKKUM	Active Galactic Nuclei in Progenitors of Massive Early-Type Galaxies at z>2
05800281	CLUSTERS OF GALAXIES	Ewan O'Sullivan	Cool Cores in Galaxy Groups
05800491	CLUSTERS OF GALAXIES	Renato Dupke	Intracluster Gas Bulk Motions in an Archived Chandra Sample
05800586	CLUSTERS OF GALAXIES	Brian McNamara	A Systematic Study of Cooling Flows and Radio Galaxies Using the Chandra Archive II
05800764	CLUSTERS OF GALAXIES	Richard Ellis	The Dark Matter Profile and Baryonic Content of Galaxy Clusters
05800771	CLUSTERS OF GALAXIES	Laurence David	The Diverse X-Ray Properties of Cool Clusters of Galaxies
05900120	EXTRAGALACTIC DIFFUSE EMISSION AND SURVEYS	Paul Green	X-ray Quasars, Buried AGN, and Clusters from the ChaMP

This proposal addresses the interplay between the formation of galaxies and their central black holes by determining the AGN fraction among the most massive gal axies yet identified at z>2. Using very deep VLT near-infrared imaging and Keck spec troscopy we have recently identified a population of red, massive galaxies at 2

Chandra and XMM have vastly improved the degree of detail with which we are able to observe galaxy groups and clusters, in the process radically changing the es timated mass deposition rates in cooling flows. We intend to study cooling at the lo w end of the mass scale, using a sample of 12 galaxy groups observed by Chandra. We will be able to derive high resolution temperature, abundance and surface brightness maps of our targets, and use these to accurately measure the mass deposition profil e within the cooling radius. We will also be able to look for the signatures of AGN or dynamical heating of the gas, and derive detailed 3-dimensional models of the gro up halo, allowing us to study variation in parameters such as entropy, cooling time and gas fraction.

Hierarchical structure formation models predict that galaxy clusters are evo lving today, with the gas possessing significant bulk motions as a result of recent mergers. These motions produce Doppler shifts of line centroids of up to 2000 km/sec and we have detected this in 10% of the sample of clusters in the ASCA archive. Wit h Chandra, we will be able to detect gas velocities at least a factor of 2 smaller ( < 1000km/s), so we should be able to map the velocity structure in many more cluster s. The improvement over ASCA is due to the extraordinary gain stability of the ACIS chips. We propose to study the velocity structure of clusters in the Chandra archive . Not only will this produce fundamental data, it will provide a new test for the va rious structure formation models.

Proposal Title: A Systematic Study of Cooling Flows and Radio Galaxies Using the Chandra Arc hive II

Using a combination of archival Chandra images, ground and HST optical and U V images, and radio images, we are reevaluating the relationship between cusps of br ight X-ray emission associated with "cooling flows" and star formation in cD galaxie s. In addition, we are testing the viability of new hydrodynamic cooling models of t he ICM that incorporate reheating by several feedback mechanisms, including radio so urces, thermal conduction, and supernova explosions. Our survey of 100 clusters will place restrictive constraints on these mechanisms, and will ultimately determine wh ether the rates of residual cooling in clusters can be reconciled with the observed levels of cool gas and star formation.

We propose a new method for measuring the shape of the dark matter (DM) halo in the inner regions of galaxy clusters, thus testing a fundamental prediction of t he Cold Dark Matter paradigm. The method consists of combining three independent, co mplementary probes of the mass (lensing, stellar kinematics, X-ray analysis) to sepa rate the baryonic from the DM components of the cluster without assuming hydrostatic equilibrium. We will apply our method to a sample of 5 clusters with isolated cDs, gravitational arcs and minimal substructure, for which archive ACIS data are suffici ently deep to recover the cluster gas density profile. Using our combined lensing, d ynamical and X-ray analyses we will achieve measures of the DM profile that cannot b e secured with any individual method on its own.

Poor clusters of galaxies, with gas temperatures between 2 and 4keV, compris e a very diverse population of objects. Within this narrow temperature range, the X- ray luminosity of these systems varies by more than a factor of 10. We have compiled a flux-limited sample of 15 cool clusters that have Chandra observations. We propos e to carry out a systematic analysis of this sample to determine the origins of the large scatter in $L_x$. This large scatter probably results from a range of dynamica l states in these systems, induced by a different formation histories. By examining the high resolution Chandra images we can detect the subtle signs of past merging an d determine the frequency of different formation histories that these systems have e xperience.

The Chandra Multiwavelength Project (ChaMP) is a serendipitous X-ray survey that is 10-100 times deeper than pre-Chandra surveys, but 70 times wider than the Ch andra deep surveys. We extrapolate a total of about 6000 sources, for which optical imaging (r<25) and spectroscopy (r<22) are in full swing, with field depths matched to Chandra flux limits. The ChaMP 1) covers enough area to populate the L-z plane 2) allows study of larger samples of rare objects such as absorbed AGN, groups and clu sters of galaxies, and 3) now provides a large, uniform, multi-wavelength public dat abase to address a wide variety of scientific questions. We require funds to extend our X-ray analysis pipeline, to produce and publicly release source lists, and to su pport our ground-based followup observations.

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