Related papers: Pulse Frequency Fluctuations of Persistent Accreti…
Using archival BATSE (Burst and Transient Source Experiment) 20-60 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…
Combining previously published pulse frequencies and BATSE measurements, we estimate the noise strengths (or power density estimates) of angular accelerations by using the root mean square residuals of angular velocity time series of OAO…
We summarize five years of continuous monitoring of accretion-powered pulsars with the Burst and Transient Source Experiment (BATSE) on the Compton Gamma Ray Observatory. Our 20-70 keV observations have determined or refined the orbital…
We present analysis of RXTE--PCA observations of GX 1+4 between March 3, 2001 and January 31, 2003 together with the CGRO--BATSE X-ray flux and frequency derivative time series between 1991 and 1999. From the timing analysis of RXTE-PCA…
The X-ray binary pulsar Her X-1 shows a wide variety of long and short term variabilities in the X-ray light curve. The 35 d variability of the source is interpreted as the influence of a warped, inclined, and twisted accretion disk…
We propose a physical model for the peaked noise in the X-ray power density spectra of accreting X-ray binaries. We interpret its appearance as an interference of two Comptonization continua: one coming from the up-scattering of seed…
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 days) with the Rossi X-Ray Timing Explorer (RXTE). Using the binary orbital parameters, obtained from…
We analyzed the rapid aperiodic X-ray variability of different types of X-ray binaries (black hole candidates, atoll sources, the recently discovered millisecond X-ray pulsar, and Z sources) at their lowest inferred mass accretion rates. At…
We analyse \emph{INTEGRAL} (between 2005 October and 2007 November) and \emph{RXTE} (between 2007 June and 2011 March) observations of the accretion powered pulsar 4U 1907+09. From \emph{INTEGRAL} IBIS-ISGRI and \emph{RXTE}-PCA…
We present timing analysis of {\emph{RXTE}}-PCA and {\emph{INTEGRAL}}-ISGRI observations of X Per between 1998 and 2010. All pulse arrival times obtained from the {\emph{RXTE}}-PCA observations are phase connected and a timing solution is…
Vela X-1 is a well-studied accreting X-ray pulsar, with a distinctive pulse profile that has been found to be very similar in different observations spread out over decades. On the other hand, significant variations down to the timescale of…
We present the broad-band noise structure of selected Anomalous X-Ray Pulsars (AXPs) and Soft Gamma Repeaters (SGRs) in the 2-60 keV energy band. We have analyzed Rossi X-ray Timing Explorer Proportional Counter Array archival light curves…
Standard shot-noise models, which seek to explain the broadband noise variability that characterises the X-ray lightcurves of X-ray binaries and active galaxies, predict that the power spectrum of the X-ray lightcurve is stationary (i.e.…
We aim to explore the properties of the Be/X-ray binary system MXB 0656-072 from a timing analysis perspective through an investigation of the RXTE/PCA and Fermi/GBM data during its 2007-2008 type I outbursts. We applied two new techniques,…
The accreting X-ray pulsar Her X-1 shows two types of long-term variations, both with periods of ~35 days: 1) Turn-on cycles, a modulation of the flux}, with a ten-day long Main-On and a five-day long Short-On, separated by two Off-states,…
Besides the narrow peaks originating from the periodic signal, the power spectra of accreting X-ray pulsars display continuum components usually increasing towards low frequencies; these arise from the source aperiodic variability. Most…
Context: Low mass X-ray binaries were found to have very low frequency breaks in their power density spectra below which the power density spectra are nearly in white noise structure and at higher frequencies they approximately follow the…
We present the spectral and timing evolution of the persistent black hole X-ray binary GRS 1758-258 based on almost 12 years of observations using the Rossi X-ray Timing Explorer Proportional Counter Array. While the source was…
Her X-1/HZ Her is one of the best studied accreting X-ray pulsars. In addition to the pulsating and orbital periods, the X-ray and optical light curves of the source exhibit an almost periodic 35-day variability caused by a precessing…
The fluctuating accretion model of Lyubarskii (1997) and its extension by Kotov et al. (2001), seeks to explain the spectral-timing properties of the X-ray variability of accreting black holes in terms of inward-propagating mass accretion…