{
  "id": "1206.0403",
  "version": "v1",
  "published": "2012-06-02T21:18:33.000Z",
  "updated": "2012-06-02T21:18:33.000Z",
  "title": "The IRAM-30m line survey of the Horsehead PDR: I. CF+ as a tracer of C+ and a measure of the Fluorine abundance",
  "authors": [
    "V. Guzmán",
    "J. Pety",
    "P. Gratier",
    "J. R. Goicoechea",
    "M. Gerin",
    "E. Roueff",
    "D. Teyssier"
  ],
  "comment": "Accepted to A&A, 4 pages, 4 figures, 2 tables",
  "categories": [
    "astro-ph.GA"
  ],
  "abstract": "C+ is a key species in the interstellar medium but its 158 {\\mu}m fine structure line cannot be observed from ground-based telescopes. Current models of fluorine chemistry predict that CF+ is the second most important fluorine reservoir, in regions where C+ is abundant. We detected the J = 1-0 and J = 2-1 rotational lines of CF+ with high signal-to-noise ratio towards the PDR and dense core positions in the Horsehead. Using a rotational diagram analysis, we derive a column density of N(CF+) = (1.5 - 2.0) \\times 10^12 cm^-2. Because of the simple fluorine chemistry, the CF+ column density is proportional to the fluorine abundance. We thus infer the fluorine gas-phase abundance to be F/H = (0.6 - 1.5) \\times 10^-8. Photochemical models indicate that CF+ is found in the layers where C+ is abundant. The emission arises in the UV illuminated skin of the nebula, tracing the outermost cloud layers. Indeed, CF+ and C+ are the only species observed to date in the Horsehead with a double peaked line profile caused by kinematics. We therefore propose that CF+, which is detectable from the ground, can be used as a proxy of the C+ layers.",
  "revisions": [
    {
      "version": "v1",
      "updated": "2012-06-02T21:18:33.000Z"
    }
  ],
  "analyses": {
    "keywords": [
      "iram-30m line survey",
      "fluorine abundance",
      "horsehead pdr",
      "column density",
      "dense core positions"
    ],
    "tags": [
      "journal article"
    ],
    "publication": {
      "doi": "10.1051/0004-6361/201219449",
      "journal": "Astronomy and Astrophysics",
      "year": 2012,
      "month": "Jul",
      "volume": 543
    },
    "note": {
      "typesetting": "TeX",
      "pages": 4,
      "language": "en",
      "license": "arXiv",
      "status": "editable",
      "inspire": 1116948,
      "adsabs": "2012A&A...543L...1G"
    }
  }
}