{
  "id": "1011.1678",
  "version": "v1",
  "published": "2010-11-07T20:49:05.000Z",
  "updated": "2010-11-07T20:49:05.000Z",
  "title": "The spectral and beaming characteristics of the anomalous X-ray pulsar 4U 0142+61",
  "authors": [
    "J. E. Trümper",
    "N. D. Kylafis",
    "Ü. Ertan",
    "A. Zezas"
  ],
  "comment": "6 pages, 3 figures, submitted to A&A",
  "categories": [
    "astro-ph.HE"
  ],
  "abstract": "AXPs and SGRs constitute a special population of young neutron stars, which are thought to be magnetars, i.e., neutron stars with super-strong magnetic fields (10^14 - 10^15 G). Assuming that AXPs and SGRs accrete matter from a fallback disk, we attempt to explain the energy-dependent pulse profiles of AXP 4U 0142+61, as well as its phase-dependent energy spectra. In the fallback disk model, the Thomson optical depth along the accretion funnel is significant and bulk-motion Comptonization operates efficiently. This is enhanced by resonant cyclotron scattering. The thus scattered photons escape mainly sideways and produce a fan beam, which is detected as a main pulse up to energies of ~160 keV. The approximately isotropic emission from the stellar surface (soft thermal photons and reflected hard X-ray ones) is detected as a secondary pulse. This secondary pulse shows a bump at an energy of ~60 keV, which may be interpreted as resonant cyclotron scattering of fan-beam photons at the neutron-star surface, implying a dipole magnetic field strength B ~7 x 10^12 (1+z) G, where z is the gravitational redshift. Our model explains the soft and hard X-ray spectra of 4U 0142+61 and its energy dependent pulse profiles of the quiescent emission, while the short bursts are due to magnetar-type processes taking place in superstrong multiple fields.",
  "revisions": [
    {
      "version": "v1",
      "updated": "2010-11-07T20:49:05.000Z"
    }
  ],
  "analyses": {
    "keywords": [
      "anomalous x-ray pulsar 4u",
      "beaming characteristics",
      "dipole magnetic field strength",
      "secondary pulse",
      "hard x-ray"
    ],
    "note": {
      "typesetting": "TeX",
      "pages": 6,
      "language": "en",
      "license": "arXiv",
      "status": "editable",
      "inspire": 875877,
      "adsabs": "2010arXiv1011.1678T"
    }
  }
}