{
  "id": "1109.2175",
  "version": "v1",
  "published": "2011-09-09T23:29:31.000Z",
  "updated": "2011-09-09T23:29:31.000Z",
  "title": "HST Observations of the Stellar Distribution Near Sgr A*",
  "authors": [
    "F. Yusef-Zadeh",
    "H. Bushouse",
    "M. Wardle"
  ],
  "comment": "16 pages, 7 figures, ApJ, in press",
  "categories": [
    "astro-ph.GA"
  ],
  "abstract": "We present HST/NICMOS data to study the surface brightness distribution of stellar light within the inner 10\" of Sgr A* at 1.4, 1.7 and 1.9 microns. We use these data to independently examine the surface brightness distribution that had been measured previously with NICMOS and to determine whether there is a drop in the surface density of stars very near Sgr A*. Our analysis confirms that a previously reported drop in the surface brightness within 0.8\" of Sgr A* is an artifact of bright and massive stars near that radius. We also show that the surface brightness profile within 5\" or ~0.2 pc of Sgr A* can be fitted with broken power laws. The power laws are consistent with previous measurements, in that the profile becomes shallower at small radii. For radii > 0.7\" the slope is beta=-0.34\\pm0.04 where Sigma is proportional to r^beta and becomes flatter at smaller radii with beta=-0.13\\pm0.04. Modeling of the surface brightness profile gives a stellar density that increases roughly as r^-1 within the inner 1\" of Sgr A*. This slope confirms earlier measurements in that it is not consistent with that expected from an old, dynamically-relaxed stellar cluster with a central supermassive black hole. Assuming that the diffuse emission is not contaminated by a faint population of young stars down to the 17.1 magnitude limit of our imaging data at 1.70$\\mu$, the shallow cusp profile is not consistent with a decline in stellar density in the inner arcsecond. In addition, converting our measured diffuse light profile to a stellar mass profile, with the assumption that the light is dominated by K0 dwarfs, the enclosed stellar mass within radius r < 0.1 pc of Sgr A* is ~ 3.2x10^4 M_solar (r/0.1 {pc})^2.1.",
  "revisions": [
    {
      "version": "v1",
      "updated": "2011-09-09T23:29:31.000Z"
    }
  ],
  "analyses": {
    "keywords": [
      "hst observations",
      "stellar distribution",
      "surface brightness distribution",
      "stellar density",
      "stellar mass"
    ],
    "tags": [
      "journal article"
    ],
    "publication": {
      "doi": "10.1088/0004-637X/744/1/24",
      "journal": "The Astrophysical Journal",
      "year": 2012,
      "month": "Jan",
      "volume": 744,
      "number": 1,
      "pages": 24
    },
    "note": {
      "typesetting": "TeX",
      "pages": 16,
      "language": "en",
      "license": "arXiv",
      "status": "editable",
      "inspire": 927169,
      "adsabs": "2012ApJ...744...24Y"
    }
  }
}