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

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


RXTE and Swift observations of SWIFT J1729.9-3437
Sahiner, S.; İNAM, SITKI ÇAĞDAŞ; Serim, Muhammed Miraç; Baykal, Altan (2013-10-01)
We analyse Rossi X-ray Timing Explorer (RXTE) and Swift observations of SWIFT J1729.9-3437 after its outburst from 2010 July 20 to 2010 August 12. We calculate a spin frequency and spin frequency derivative of 1.8734(8) x 10(-3) Hz and 6.42(6) x 10(-12) Hz s(-1), respectively from the quadratic fit of the pulse arrival times. The quadratic fit residuals fit well to a circular orbital model with a period of 15.3(2) d and a mass function of about 1.3 M-circle dot, but they can also be explained by a torque no...
Differences between the two anomalous X-ray pulsars: variations in the spin-down rate of 1E 1048.1-5937 and an extended interval of quiet spin-down in 1E 2259+586
Baykal, Altan; Swank, J; Alpar, MA; Stark, MJ (2000-11-21)
We analysed the Rossi X-ray Timing Explorer (RXTE) archival data of 1E 1048.1-5937 covering a time-span of more than one year. The spin-down rate of this source decreases by similar to 30 per cent during the observation. We could not resolve the X-ray flux variations because of contamination by eta Carinae. We find that the level of pulse frequency fluctuations of 1E 1048.1-5937 is consistent with typical noise levels of accretion-powered pulsars. Recent RXTE observations of 1E 2259+586 have shown a constan...
RXTE timing analysis of the anomalous X-ray pulsar 1E 2259+586
Icdem, B.; Baykal, Altan; İNAM, SITKI ÇAĞDAŞ (2012-02-01)
We present a pulse-timing analysis of Rossi X-ray Timing Explorer (RXTE) observations of the anomalous X-ray pulsar 1E 2259+586 from its 2002 outburst to 2010 October. We have the following objectives: to extend the work on the recovery stage after the 2002 glitch; to investigate the variations caused by the second glitch that occurred in 2007; to look for other unusual events, if any, that arise in the regular spin-down trend of the source. We find that the fractional change in the spin frequency derivativ...
Spin-down rate of 1E 2259+586 from RXTE observation
Baykal, Altan; Strohmayer, T; Stark, MJ (1998-08-01)
We present new X-ray observations of the X-ray pulsar 1E 2259+586, obtained during March 1997, with the Rossi X-Ray Timing Explorer (RXTE). We have measured the pulse frequency derivative (nu) over dot = (-1.08 +/- 0.04) x 10(-14) Hz s(-1) from pulse arrival times obtained in a sequence of 5 observations spread over one month. This (nu) over dot is consistent with the long term spin-down trend. We also found that the observed X-ray luminosity is consistent with that measured at quiescent X-ray flux levels b...
Short-term pulse frequency fluctuations of OAO 1657-415 from RXTE observations
Baykal, Altan (2000-04-11)
We present new X-ray observations of the high-mass X-ray binary (HMXRB) pulsar OAO 1657-415, obtained during one orbital period (10.44 d) with the Rossi X-Ray Timing Explorer (RXTE). Using the binary orbital parameters, obtained from Burst and Transient Source Experiment (BATSE) observations, we resolve the fluctuations in the pulse frequency at time-scales on the order of 1 d for the first time. Recent BATSE results by Baykal showed that OAO 1657-415 has spin-up/down trends in its pulse frequency time seri...
Citation Formats
A. Baykal, M. J. Stark, C. M. Heffner, A. E. Erkoca, and J. H. Swank, “Timing studies on RXTE observations of SAX J2103.5+4545,” MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY, pp. 1108–1114, 2007, Accessed: 00, 2020. [Online]. Available: https://hdl.handle.net/11511/41726.