{
  "id": "1404.0403",
  "version": "v1",
  "published": "2014-04-01T21:27:05.000Z",
  "updated": "2014-04-01T21:27:05.000Z",
  "title": "The physical characteristics of the gas in the disk of Centaurus A using the Herschel Space Observatory",
  "authors": [
    "T. J. Parkin",
    "C. D. Wilson",
    "M. R. P. Schirm",
    "M. Baes",
    "M. Boquien",
    "A. Boselli",
    "D. Cormier",
    "M. Galametz",
    "O. Ł. Karczewski",
    "V. Lebouteiller",
    "I. De Looze",
    "S. C. Madden",
    "H. Roussel",
    "M. W. L. Smith",
    "L. Spinoglio"
  ],
  "comment": "Accepted for publication in the Astrophysical Journal. 22 pages, 10 figures, 5 tables",
  "categories": [
    "astro-ph.GA"
  ],
  "abstract": "We search for variations in the disk of Centaurus A of the emission from atomic fine structure lines using Herschel PACS and SPIRE spectroscopy. In particular we observe the [C II](158 $\\mu$m), [N II](122 and 205 $\\mu$m), [O I](63 and 145 $\\mu$m) and [O III](88 $\\mu$m) lines, which all play an important role in cooling the gas in photo-ionized and photodissociation regions. We determine that the ([C II]+[O I]$_{63}$)/$F_{TIR}$ line ratio, a proxy for the heating efficiency of the gas, shows no significant radial trend across the observed region, in contrast to observations of other nearby galaxies. We determine that 10 - 20% of the observed [C II] emission originates in ionized gas. Comparison between our observations and a PDR model shows that the strength of the far-ultraviolet radiation field, $G_0$, varies between $10^{1.75}$ and $10^{2.75}$ and the hydrogen nucleus density varies between $10^{2.75}$ and $10^{3.75}$ cm$^{-3}$, with no significant radial trend in either property. In the context of the emission line properties of the grand-design spiral galaxy M51 and the elliptical galaxy NGC 4125, the gas in Cen A appears more characteristic of that in typical disk galaxies rather than elliptical galaxies.",
  "revisions": [
    {
      "version": "v1",
      "updated": "2014-04-01T21:27:05.000Z"
    }
  ],
  "analyses": {
    "keywords": [
      "herschel space observatory",
      "physical characteristics",
      "significant radial trend",
      "atomic fine structure lines",
      "hydrogen nucleus density varies"
    ],
    "tags": [
      "journal article"
    ],
    "publication": {
      "doi": "10.1088/0004-637X/787/1/16",
      "journal": "The Astrophysical Journal",
      "year": 2014,
      "month": "May",
      "volume": 787,
      "number": 1,
      "pages": 16
    },
    "note": {
      "typesetting": "TeX",
      "pages": 22,
      "language": "en",
      "license": "arXiv",
      "status": "editable",
      "adsabs": "2014ApJ...787...16P"
    }
  }
}