{
  "id": "1607.07125",
  "version": "v1",
  "published": "2016-07-25T01:29:58.000Z",
  "updated": "2016-07-25T01:29:58.000Z",
  "title": "No Signatures of Black-Hole Spin in the X-ray Spectrum of the Seyfert 1 Galaxy Fairall 9",
  "authors": [
    "Tahir Yaqoob",
    "Tracey Jane Turner",
    "Malachi M. Tatum",
    "Max Trevor",
    "Alexis Scholtes"
  ],
  "comment": "21 pages, 2 tables, 6 figures, accepted by MNRAS. arXiv admin note: text overlap with arXiv:1508.07685",
  "categories": [
    "astro-ph.HE"
  ],
  "abstract": "Fairall 9 is one of several type 1 active galactic nuclei for which it has been claimed that the angular momentum (or spin) of the supermassive black hole can be robustly measured, using the Fe K$\\alpha$ emission line and Compton-reflection continuum in the X-ray spectrum. The method rests upon the interpretation of the Fe K$\\alpha$ line profile and associated Compton-reflection continuum in terms of relativistic broadening in the strong gravity regime in the innermost regions of an accretion disc, within a few gravitational radii of the black hole. Here, we re-examine a Suzaku X-ray spectrum of Fairall 9 and show that a face-on toroidal X-ray reprocessor model involving only nonrelativistic and mundane physics provides an excellent fit to the data. The Fe K$\\alpha$ line emission and Compton reflection continuum are calculated self-consistently, the iron abundance is solar, and an equatorial column density of $\\sim 10^{24} \\ \\rm cm^{-2}$ is inferred. In this scenario, neither the Fe K$\\alpha$ line, nor the Compton-reflection continuum provide any information on the black-hole spin. Whereas previous analyses have assumed an infinite column density for the distant-matter reprocessor, the shape of the reflection spectrum from matter with a finite column density eliminates the need for a relativistically broadened Fe K$\\alpha$ line. We find a 90 per cent confidence range in the Fe K$\\alpha$ line FWHM of $1895$-$6205 \\ \\rm km \\ s^{-1}$, corresponding to a distance of $\\sim 3100$ to $33,380$ gravitational radii from the black hole, or $0.015$-$0.49$ pc for a black-hole mass of $\\sim 1-3 \\times 10^{8} \\ M_{\\odot}$.",
  "revisions": [
    {
      "version": "v1",
      "updated": "2016-07-25T01:29:58.000Z"
    }
  ],
  "analyses": {
    "keywords": [
      "x-ray spectrum",
      "black-hole spin",
      "galaxy fairall",
      "black hole",
      "compton-reflection continuum"
    ],
    "note": {
      "typesetting": "TeX",
      "pages": 21,
      "language": "en",
      "license": "arXiv",
      "status": "editable"
    }
  }
}