A Catalog of X-ray Point Sources from Two Megaseconds of Chandra Observations of the Galactic Center

Abstract

We present a catalog of 9017 X-ray sources identified in Chandra observations of a 2×0.8 field around the Galactic center. This enlarges the number of known X-ray sources in the region by a factor of 2.5. The catalog incorporates all of the ACIS-I observations as of 2007 August, which total 2.25 Msec of exposure. At the distance to the Galactic center (8 kpc), we are sensitive to sources with luminosities of 4× 10 erg s (0.5–8.0 keV; 90% confidence) over an area of one square degree, and up to an order of magnitude more sensitive in the deepest exposure (1.0 Msec) around Sgr A. The positions of 60% of our sources are accurate to <1(95% confidence), and 20% have positions accurate to <0. 5. We search for variable sources, and find that 3% exhibit flux variations within an observation, 10% exhibit variations from observation-to-observation. We also find one source, CXOUGC J174622.7–285218, with a periodic 1745 s signal (1.4% chance probability), which is probably a magnetically-accreting cataclysmic variable. We compare the spatial distribution of Xray sources to a model for the stellar distribution, and find 2.8σ evidence for excesses in the numbers of X-ray sources in the region of recent star formation encompassed by the Arches, Quintuplet, and Galactic center star clusters. These excess sources are also seen in the luminosity distribution of the X-ray sources, which is flatter near the Arches and Quintuplet than elsewhere in the field. These excess point sources, along with a similar longitudinal asymmetry in the distribution of diffuse iron emission that has been reported by other authors, probably have their origin in the young stars that are prominent at l≈0.1. Subject headings: Galaxy: center — X-rays: stars 1 Space Radiation Laboratory, California Institute of Technology, Pasadena, CA 91104; mmuno@srl.caltech.edu 2 Columbia Astrophysical Laboratory, New York, NY, 10027, feb@astro.columbia.edu 3 Kavli Institute for Astrophysics and Space Research, Massachusetts Institute of Technology, Cambridge, MA 02139 4 Department of Astronomy, University of Florida, Gainesville, FL 32611 5 Department of Astronomy and Radio Astronomy Laboratory, University of California, Berkeley, CA 94720-3411 6 Department of Astronomy and Astrophysics, The Pennsylvania State University, University Park, PA 16802 7 SETI Institute, 515 N. Whisman Rd., Mountain View, CA 8 Department of Physics and Engineering, Sweet Briar College, Sweet Briar, VA 24595 9 Remote Sensing Division, Naval Research Laboratory, Washington, DC 20375-5351 10 Department of Physics and Astronomy, University of Iowa, Van Allen Hall, Iowa City, IA 52242 11 Astronomical Institute “Anton Pannekoek”, University of Amsterdam, Kruislaan 403, 1098 SJ, The Netherlands 12 Department of Physics and Astronomy, University of California, Los Angeles, CA 90095 13 Department of Astronomy, Kyoto University, Kyoto 606-8502, Japan 14 National Astronomical Observatory of Japan (NAOJ), National Institutes of Natural Sciences (NINS), Tokyo 181-8588, Japan 15 Spitzer Science Center, California Institute of Technology, Pasadena, CA 91125 16 Astronomy Department, University of Massachusetts, Amherst, MA 01003, USA 17 Department of Physics, McGill University, Montreal, QC H3A 2T8, Canada 18 Department of Physics and Astronomy, Northwestern University, Evanston, IL 60208

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@inproceedings{Muno2008ACO, title={A Catalog of X-ray Point Sources from Two Megaseconds of Chandra Observations of the Galactic Center}, author={Michael P . Muno and Franz E. Bauer and Frederick K. Baganoff and R. M. Bandyopadhyay and Geoffrey C. Bower and William N. Brandt and Patrick S. Broos and Gordon P. Garmire and S. D. Hyman and Namir E. Kassim and Cornelia C. Lang}, year={2008} }