Timing studies on RXTE observations of SAX J2103.5+4545

Creative Commons License

Baykal A., Inam S. C., Stark M. J., Heffner C. M., Erkoca A. E., Swank J. H.

MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY, vol.374, no.3, pp.1108-1114, 2007 (SCI-Expanded) identifier identifier

  • Publication Type: Article / Article
  • Volume: 374 Issue: 3
  • Publication Date: 2007
  • Doi Number: 10.1111/j.1365-2966.2006.11231.x
  • Journal Indexes: Science Citation Index Expanded (SCI-EXPANDED), Scopus
  • Page Numbers: pp.1108-1114
  • Keywords: accretion, accretion discs, stars : neutron, pulsars : individual : SAX J2103.5+4545, X-rays : binaries, X-RAY SOURCES, MAGNETIZED NEUTRON-STARS, PULSAR SAX-J2103.5+4545, LUMINOSITY DEPENDENCE, ACCRETING PULSARS, DISCOVERY, TORQUE, ORBIT, EXO-2030+375, SPECTRA
  • Middle East Technical University Affiliated: Yes


SAX J2103.5+4545 has been continuously monitored for similar to 900 d by the Rossi X-ray Timing Explorer (RXTE) since its outburst in 2002 July. Using these observations and previous archival RXTE observations of SAX J2103.5+4545, we refined the binary orbital parameters and find the new orbital period as P = (12.665 36 +/- 0.000 88) d and the eccentricity as 0.4055 +/- 0.0032. With these new orbital parameters, we constructed the pulse frequency and pulse frequency derivative histories of the pulsar and confirmed the correlation between X-ray flux and pulse frequency derivative presented by Baykal, Stark & Swank. We constructed the power spectra for the fluctuations of pulse frequency derivatives and found that the power-law index of the noise spectra is 2.13 +/- 0.6. The power-law index is consistent with random walk in pulse frequency derivative and is the steepest among the HMXRBs. X-ray spectra analysis confirmed the inverse correlation trend between power-law index and X-ray flux found by Baykal et al.