{
  "id": "1412.2425",
  "version": "v1",
  "published": "2014-12-08T01:39:47.000Z",
  "updated": "2014-12-08T01:39:47.000Z",
  "title": "A Possible Extension of the Scutum-Centaurus Arm into the Outer Second Quadrant",
  "authors": [
    "Yan Sun",
    "Ye Xu",
    "Ji Yang",
    "Fa Cheng Li",
    "Xin Yu Du",
    "Shao Bo Zhang",
    "Xin Zhou"
  ],
  "comment": "11 pages, 3 figures; Accepted for publication in ApJ Letters",
  "categories": [
    "astro-ph.GA"
  ],
  "abstract": "Combining HI data from the Canadian Galactic Plane Survey~(CGPS) and CO data from the Milky Way Imaging Scroll Painting (MWISP) project, we have identified a new segment of a spiral arm between Galactocentric radii of 15 and 19~kpc that apparently lies beyond the Outer Arm in the second Galactic quadrant. Over most of its length, the arm is 400-600 pc thick in $z$. The new arm appears to be the extension of the distant arm recently discovered by Dame & Thaddeus (2011) as well as the Scutum-Centaurus Arm into the outer second quadrant. Our current survey identified a total of 72 molecular clouds with masses on the order of 10$^2$-10$^4$M$_{\\sun}$ that probably lie in the new arm. When all of the available data from the CO molecular clouds are fit, the best$-$fitting spiral model gives a pitch angle of 9.3$^{\\circ}$ $\\pm$0.7$^{\\circ}$.",
  "revisions": [
    {
      "version": "v1",
      "updated": "2014-12-08T01:39:47.000Z"
    }
  ],
  "analyses": {
    "keywords": [
      "outer second quadrant",
      "scutum-centaurus arm",
      "way imaging scroll painting",
      "molecular clouds",
      "canadian galactic plane"
    ],
    "tags": [
      "journal article"
    ],
    "publication": {
      "doi": "10.1088/2041-8205/798/2/L27",
      "journal": "The Astrophysical Journal",
      "year": 2015,
      "month": "Jan",
      "volume": 798,
      "number": 2
    },
    "note": {
      "typesetting": "TeX",
      "pages": 11,
      "language": "en",
      "license": "arXiv",
      "status": "editable",
      "adsabs": "2015ApJ...798L..27S"
    }
  }
}