arXiv subjects
Publications and source records attributed to B. Icdem.
In this paper, we present the re-analysis of a set of RXTE-PCA observations of OAO 1657-415 during 1997 August 20-27. We found a revised timing solution which was found to fit better to the data and updated pulse frequency values accordingly. We also verified that there is a marginal correlation between the gradual spin-up (or decrease in spin-down rate) and increase in X-ray luminosity as suggested by Baykal (2000).
In this paper, we analyzed pulse profiles of Swift J1626.6+5156 using the lightcurves from RXTE-PCA observations between MJD 53724 (just after the outburst) and MJD 55113 and a Chandra-ACIS dataset on MJD 54897 with a 20 ks exposure. We found that pulse profiles show morphological variations and pulsations do not cease even $\sim 1200$ days after the outburst. Despite these variations, we did not find any significant variation in the pulsed fraction with decreasing X-ray flux.
In this paper, we extend timing analysis of Baykal et al. (2010) of \src using RXTE-PCA observations between MJD 53724 and MJD 55113 together with a Chandra-ACIS observation on MJD 54897 with a 20 ks exposure. We also present X-ray spectral analysis of these RXTE and Chandra observations. We find that the spin-up rate of the source is correlated with the X-ray flux. Using this correlation, we estimate the distance and surface magnetic field of the source as $\sim 15$kpc and $\sim 9\times 10^{11}$Gauss respectively. From the spectral analysis, we found that power law index increases and Hydrogen column density decreases with decreasing flux.