X-ray enhancement and long-term evolution of Swift J1822.3-1606


Benli O., Çalişkan S., Ertan U., Alpar M., Trümper J., Kylafis N.

Astrophysical Journal, vol.778, no.2, 2013 (SCI-Expanded) identifier identifier

  • Publication Type: Article / Article
  • Volume: 778 Issue: 2
  • Publication Date: 2013
  • Doi Number: 10.1088/0004-637x/778/2/119
  • Journal Name: Astrophysical Journal
  • Journal Indexes: Science Citation Index Expanded (SCI-EXPANDED), Scopus
  • Keywords: accretion, accretion disks, pulsars: individual (AXPs), stars: neutron, X-rays: bursts
  • TED University Affiliated: No

Abstract

We investigate the X-ray enhancement and the long-term evolution of the recently discovered second "low-B magnetar" Swift J1822.3-1606 in the frame of the fallback disk model. During a soft gamma burst episode, the inner disk matter is pushed back to larger radii, forming a density gradient at the inner disk. Subsequent relaxation of the inner disk could account for the observed X-ray enhancement light curve of Swift J1822.3-1606. We obtain model fits to the X-ray data with basic disk parameters similar to those employed to explain the X-ray outburst light curves of other anomalous X-ray pulsars and soft gamma repeaters. The long period (8.4 s) of the neutron star can be reached by the effect of the disk torques in the long-term accretion phase ((1-3) × 105 yr). The currently ongoing X-ray enhancement could be due to a transient accretion epoch, or the source could still be in the accretion phase in quiescence. Considering these different possibilities, we determine the model curves that could represent the long-term rotational and the X-ray luminosity evolution of Swift J1822.3-1606, which constrain the strength of the magnetic dipole field to the range of (1-2) × 1012 G on the surface of the neutron star. © 2013. The American Astronomical Society. All rights reserved.