{
  "id": "1209.6420",
  "version": "v1",
  "published": "2012-09-28T04:14:20.000Z",
  "updated": "2012-09-28T04:14:20.000Z",
  "title": "Detection of Interstellar C_2 and C_3 in the Small Magellanic Cloud",
  "authors": [
    "Daniel E. Welty",
    "J. Christopher Howk",
    "Nicolas Lehner",
    "John H. Black"
  ],
  "comment": "accepted to MNRAS; 10 pages, 6 figures",
  "categories": [
    "astro-ph.GA"
  ],
  "abstract": "We report the detection of absorption from interstellar C_2 and C_3 toward the moderately reddened star Sk 143, located in the near 'wing' region of the SMC, in optical spectra obtained with the ESO VLT/UVES. These detections of C_2 (rotational levels J=0-8) and C_3 (J=0-12) absorption in the SMC are the first beyond our Galaxy. The total abundances of C_2 and C_3 (relative to H_2) are similar to those found in diffuse Galactic molecular clouds -- as previously found for CH and CN -- despite the significantly lower average metallicity of the SMC. Analysis of the rotational excitation of C_2 yields an estimated kinetic temperature T_k ~ 25 K and a moderately high total hydrogen density n_H ~ 870 cm^-3 -- compared to the T_01 ~ 45 K and n_H ~ 85-300 cm^-3 obtained from H_2. The populations of the lower rotational levels of C_3 are consistent with an excitation temperature of about 34 K.",
  "revisions": [
    {
      "version": "v1",
      "updated": "2012-09-28T04:14:20.000Z"
    }
  ],
  "analyses": {
    "keywords": [
      "small magellanic cloud",
      "interstellar",
      "moderately high total hydrogen density",
      "diffuse galactic molecular clouds",
      "lower rotational levels"
    ],
    "tags": [
      "journal article"
    ],
    "publication": {
      "doi": "10.1093/mnras/sts093",
      "journal": "Monthly Notices of the Royal Astronomical Society",
      "year": 2013,
      "month": "Jan",
      "volume": 428,
      "number": 2,
      "pages": 1107
    },
    "note": {
      "typesetting": "TeX",
      "pages": 10,
      "language": "en",
      "license": "arXiv",
      "status": "editable",
      "inspire": 1188643,
      "adsabs": "2013MNRAS.428.1107W"
    }
  }
}