{
  "id": "0907.1935",
  "version": "v2",
  "published": "2009-07-11T02:39:38.000Z",
  "updated": "2009-08-21T01:30:28.000Z",
  "title": "Near-Infrared Counterparts to Chandra X-ray Sources toward the Galactic Center. I. Statistics and a Catalog of Candidates",
  "authors": [
    "Jon C. Mauerhan",
    "Michael P. Muno",
    "Mark R. Morris",
    "Franz E. Bauer",
    "Shogo Nishiyama",
    "Tetsuya Nagata"
  ],
  "comment": "Submitted to ApJ January 16, 2009; accepted July 21, 2009; 30 pages, 6 figures",
  "journal": "Astrophys.J.703:30-41,2009",
  "doi": "10.1088/0004-637X/703/1/30",
  "categories": [
    "astro-ph.GA"
  ],
  "abstract": "We present a catalog of 5184 candidate infrared counterparts to X-ray sources detected towards the Galactic center. The X-ray sample contains 9017 point sources detected in this region by the Chandra X-ray Observatory, including data from a recent deep survey of the central 2 x 0.8 deg of the Galactic plane. A total of 6760 of these sources have hard X-ray colors, and the majority of them lie near the Galactic center, while most of the remaining 2257 soft X-ray sources lie in the foreground. We cross-correlated the X-ray source positions with the 2MASS and SIRIUS near-infrared catalogs, which collectively contain stars with a 10-sigma limiting flux of K_s<=15.6 mag. In order to distinguish absorbed infrared sources near the Galactic center from those in the foreground, we defined red and blue sources as those which have H-K_s>=0.9 and <=0.9 mag, respectively. We find that 5.8(1.5)% of the hard X-ray sources have real infrared counterparts, of which 228(99) are red and 166(27) are blue. The red counterparts are probably comprised of WR/O stars, HMXBs, and symbiotics near the Galactic center. We also find that 39.4(1.0)% of the soft X-ray sources have blue infrared counterparts; most of these are probably coronally active dwarfs in the foreground. There is a noteworthy collection of ~20 red counterparts to hard X-ray sources near the Sagittarius-B H II region, which are probably massive binaries that have formed within the last several Myr. For each of the infrared matches to X-ray sources in our catalog we derived the probability that the association is real, based on the results of the cross-correlation analysis. The catalog will serve spectroscopic surveys to identify infrared counterparts to X-ray sources near the Galactic center.",
  "revisions": [
    {
      "version": "v2",
      "updated": "2009-08-21T01:30:28.000Z"
    }
  ],
  "analyses": {
    "keywords": [
      "galactic center",
      "chandra x-ray sources",
      "near-infrared counterparts",
      "hard x-ray sources",
      "statistics"
    ],
    "tags": [
      "journal article"
    ],
    "publication": {
      "journal": "The Astrophysical Journal",
      "year": 2009,
      "month": "Sep",
      "volume": 703,
      "number": 1,
      "pages": 30
    },
    "note": {
      "typesetting": "TeX",
      "pages": 30,
      "language": "en",
      "license": "arXiv",
      "status": "editable",
      "inspire": 825475,
      "adsabs": "2009ApJ...703...30M"
    }
  }
}