Related papers: Pulse Frequency Fluctuations of Persistent Accreti…
This work presents a comprehensive timing and spectral analysis of high-mass X-ray binary pulsar, OAO 1657-415 by using the observation made with Nuclear Spectroscopic Telescope Array (NuSTAR) on June 2019. During this observation, OAO…
We have carried out a timing analysis of Cyg X-1 and GRS 1915+105 using more than 5 years worth of data from the All Sky Monitor (ASM) on board RXTE. We have obtained for the first time power density spectra, colour-colour and…
We study RXTE PCA data for the high mass X-ray binary source SMC X-1 between 2003-10 and 2003-12 when the source was in high states. The source is found to be frequently bursting which can be seen as flares in lightcurves on an average of…
As part of our multiwavelength campaign of GX 339-4 observations in 1996 we present the rapid X-ray variability observed July 26 using the RXTE when the source was in a hard state (= soft X-ray low state). We found that the source was…
Long uninterrupted observations of the X-ray binary system Her X-1 were performed with the Mikhail Pavlinsky ART-XC telescope of the Spectrum-R\"ontgen-Gamma (SRG) X-ray Observatory in the 4--25 keV energy range with a total exposure of…
Black hole X-ray binaries display significant stochastic variability on short time-scales (0.01-100 seconds), with a complex pattern of lags in correlated variability seen in different energy bands. This behaviour is generally interpreted…
Pulsars show two classes of rotational irregularities that can be used to understand neutron-star interiors and magnetospheres: glitches and timing noise. Here we present an analysis of the Vela pulsar spanning nearly 21 yr of observation…
We analyzed RXTE-PCA observations of a recent outburst of the X-ray pulsar XMMU J054134.7$-$682550. We calculated the pulse frequency history of the source. We found no sign of a binary companion. The source spins up when the X-ray flux is…
We have constructed timing solutions for 81 gamma-ray pulsars covering more than five years of Fermi data. The sample includes 37 radio-quiet or radio-faint pulsars which cannot be timed with other telescopes. These timing solutions and the…
We report on the spectral (pulse averaged) and timing analysis of the ~ 20 ksec observation of the X-ray binary pulsar Vela X-1 performed during the BeppoSAX Science Verification Phase. The source was observed in two different intensity…
The X-ray variability in the soft X-ray spectral state of black hole binaries is primarily characterized by a power-law noise (PLN), which is thought to originate from the propagation of the modulation in the mass accretion rate of a…
Many nearby AGNs display a significant short-term variability. In this work we re-analyze photometric data of four active galactic nuclei observed by Kepler in order to study the flickering activity, having as main goal that of searching…
We present a quantitative analysis of the X-ray spectrum of the eclipsing high mass X-ray binary Vela X-1 (4U 0900-40) using archival data from ASCA. The observation covers a time interval centered on eclipse of the X-ray pulsar by the…
The high-frequency bump, characterized by a frequency exceeding ~30 Hz, represents a seldom-explored time-variability feature in the power density spectrum (PDS) of black-hole X-ray binaries. In the 2002, 2004, 2007 and 2010 outbursts of GX…
We have used INTEGRAL & RXTE data to investigate the timing properties of the source in correlation with its spectral states as defined by different positions in the colour-colour diagram. The source shows two distinct branches in the…
We represent noise strength analysis of Anomalous X-Ray Pulsars (AXPs) 4U 0142+61, 1RXS J170849.9-400910, 1E 1841-045, 1E 2259+586 and Soft Gamma Repeaters (SGRs) SGR J1833-0832, SWIFT J1822.3-1606 and SWIFT J1834.9-0846 together with the…
We report the first detection of radio emission from any anomalous X-ray pulsar (AXP). Data from the Very Large Array (VLA) MAGPIS survey with angular resolution 6" reveals a point-source of flux density 4.5 +/- 0.5 mJy at 1.4 GHz at the…
RXTE ASM count rates from the X-ray pulsar Her X-1 began falling consistently during the late months of 2003. The source is undergoing another state transition similar to the anomalous low state of 1999. This new event has triggered…
High time-resolution observations of pulsars were carried out at 35 MHz, using the Gauribidanur Radio Telescope (India), to study the spectra of intrinsic pulse-to-pulse fluctuations. Our sample consists of a few bright pulsars, each of…
We explore the non-linear, high-frequency, aperiodic variability properties in the three cataclysmic variables MV Lyr, KIC 8751494 and V1504 Cyg observed with Kepler, as well as the X-ray binary Cyg X-1 observed with RXTE. This is done…