X-ray flux and pulse frequency changes of three high mass X-ray binary pulsars: Vela X-1, GX 301-2 and OAO 1657-415

Inam S., Baykal A.

ASTRONOMY & ASTROPHYSICS, vol.353, no.2, pp.617-623, 2000 (SCI-Expanded) identifier

  • Publication Type: Article / Article
  • Volume: 353 Issue: 2
  • Publication Date: 2000
  • Journal Name: ASTRONOMY & ASTROPHYSICS
  • Journal Indexes: Science Citation Index Expanded (SCI-EXPANDED), Scopus
  • Page Numbers: pp.617-623
  • Keywords: X-rays : stars, accretion, accretion disks, stars : pulsars : individual : OAO 1657-415, stars : pulsars : individual : GX 301-2, stars : pulsars : individual : Vela X1, THREADED ACCRETION DISK, MAGNETIC NEUTRON STARS, STELLAR WIND, ORBITAL ELEMENTS, CENTAURUS X-3, 3U 0900-40, TORQUE, MODEL, DISCOVERY, PERIOD
  • Middle East Technical University Affiliated: Yes

Abstract

Using archival BATSE (Burst and Transient Source Experiment) 20-50 keV band X-ray flux and pulse frequency time series, we look for correlations between torque, luminosity and specific angular momentum for three high mass X-ray binary pulsars Vela X-1, GX 301-2 and OAO 1657-415. Our results show that there is no correlation between pulse frequency derivative and flux which may be an indication of the absence of stable prograde accretion disk. From the strong correlation of specific angular momentum and torque, we conclude that the accretion geometry changes continuously as suggested by the hydrodynamic simulations (Blondin et al. 1990).