{
  "id": "1411.4349",
  "version": "v1",
  "published": "2014-11-17T03:14:52.000Z",
  "updated": "2014-11-17T03:14:52.000Z",
  "title": "CO observations of a sample towards nearby galaxies",
  "authors": [
    "Fa-Cheng Li",
    "Yuan-Wei Wu",
    "Ye Xu"
  ],
  "comment": "17 pages, 4 figures, accepted for publication in RAA journal",
  "categories": [
    "astro-ph.GA"
  ],
  "abstract": "We have simultaneously observed $^{12}$CO, $^{13}$CO, and C$^{18}$O (J=1$-$0) rotational transitions in the centers of a sample of 58 nearby spiral galaxies using the 13.7-m millimeter-wave telescope of the Purple Mountain Observatory. Forty-two galaxies were detected in $^{13}$CO emission, but there was a null detection for C$^{18}$O emission with a sigma upper limit of 2 mK. Central beam ratios, \\R, of $^{12}$CO and $^{13}$CO range mostly from 5 to 13, with an average value of 8.1$\\pm$4.2, which is slightly lower than previous estimates for normal galaxies. Clear correlations are found between $^{12}$CO and $^{13}$CO luminosities. An average $X$-factor of $1.44\\pm0.84\\times10^{20}\\ \\mathrm{cm}^{-2} (\\mathrm{K} \\mathrm{km} \\mathrm{s}^{-1})^{-1}$ is slightly lower than that in the Milky Way.",
  "revisions": [
    {
      "version": "v1",
      "updated": "2014-11-17T03:14:52.000Z"
    }
  ],
  "analyses": {
    "keywords": [
      "nearby galaxies",
      "observations",
      "nearby spiral galaxies",
      "slightly lower",
      "purple mountain observatory"
    ],
    "publication": {
      "doi": "10.1088/1674-4527/15/6/002",
      "journal": "Research in Astronomy and Astrophysics",
      "year": 2015,
      "month": "Jun",
      "volume": 15,
      "number": 6,
      "pages": 785
    },
    "note": {
      "typesetting": "TeX",
      "pages": 17,
      "language": "en",
      "license": "arXiv",
      "status": "editable",
      "adsabs": "2015RAA....15..785L"
    }
  }
}