{
  "id": "1106.2140",
  "version": "v1",
  "published": "2011-06-10T18:30:04.000Z",
  "updated": "2011-06-10T18:30:04.000Z",
  "title": "Is Calvera a Gamma-ray Pulsar?",
  "authors": [
    "J. P. Halpern"
  ],
  "comment": "5 pages, 4 figures, to appear in The Astrophysical Journal Letters",
  "categories": [
    "astro-ph.HE"
  ],
  "abstract": "Originally selected as a neutron star (NS) candidate in the ROSAT All-Sky Survey, 1RXS J141256.0+792204 (\"Calvera\") was discovered to be a 59 ms X-ray pulsar in a pair of XMM-Newton observations (Zane et al. 2011). Surprisingly, their claimed detection of this pulsar in Fermi gamma-ray data requires no period derivative, severely restricting its dipole magnetic field strength, spin-down luminosity, and distance to small values. This implies that the cooling age of Calvera is much younger than its characteristic spin-down age. If so, it could be a mildly recycled pulsar, or the first \"orphaned\" central compact object (CCO). Here we show that the published Fermi ephemeris fails to align the pulse phases of the two X-ray observations with each other, which indicates that the Fermi detection is almost certainly spurious. Analysis of additional Fermi data also does not confirm the gamma-ray detection. This leaves the spin-down rate of Calvera less constrained, and its place among the families of NSs uncertain. It could still be either a normal pulsar, a mildly recycled pulsar, or an orphaned CCO.",
  "revisions": [
    {
      "version": "v1",
      "updated": "2011-06-10T18:30:04.000Z"
    }
  ],
  "analyses": {
    "keywords": [
      "gamma-ray pulsar",
      "dipole magnetic field strength",
      "mildly recycled pulsar",
      "rosat all-sky survey",
      "ms x-ray pulsar"
    ],
    "tags": [
      "journal article"
    ],
    "publication": {
      "doi": "10.1088/2041-8205/736/1/L3",
      "journal": "The Astrophysical Journal",
      "year": 2011,
      "month": "Jul",
      "volume": 736,
      "number": 1
    },
    "note": {
      "typesetting": "TeX",
      "pages": 5,
      "language": "en",
      "license": "arXiv",
      "status": "editable",
      "inspire": 913323,
      "adsabs": "2011ApJ...736L...3H"
    }
  }
}