Related papers: The cross-correlation analysis in Z source GX 349+…

We report the detections of the anti-correlated soft and hard X-rays, and the time lags of $\sim$ hecto-second from the neutron star low-mass X-ray binary Cyg X-2, a well-known Z-type luminous source. Both the anti-correlation and the…

We investigate the nature of the inner accretion disk in the neutron star source GX 5-1 by making a detailed study of time lags between X-rays of different energies. Using the cross-correlation analysis, we found anti-correlated hard and…

Studying the cross-correlation function between the soft and hard X-ray emission in Neutron Star Low Mass X-ray Binaries provides crucial insight into the structure and dynamics of the innermost accretion regions. In this work, we…

We present an extended corona model based on ray-tracing simulations to investigate X-ray time lags in Active Galactic Nuclei (AGN). This model consists of two axial point sources illuminating an accretion disc that produce the…

We investigate the accretion disk geometry in Galactic black hole sources by measuring the time delay between soft and hard X-ray emissions. Similar to the recent discoveries of anti-correlated hard X-ray time lags in Cyg X-3 and GRS…

We report the few hundred second anti-correlated soft lags between soft and hard energy bands in the source GX 339-4 using RXTE observations. In one observation, anti-correlated soft lags were observed using the ISGRI/INTEGRAL hard energy…

Multi-wavelength observations of Galactic black hole candidate sources indicate a close connection between the accretion disk emission and the jet emission. The recent discovery of an anti-correlated time lag between the soft and hard…

With Rossi X-ray Timing Explorer (RXTE) data, we systematically study the cross-correlation and time lag in all spectral states of black hole X-ray binary (BHXB) XTE J1859+226 in detail during its entire 1999-2000 outburst that lasted for…

Using simultaneous observations in X-rays and optical, we have performed a homogeneous analysis of the cross-correlation behaviours of four X-ray binaries: SWIFT J1753.5-0127, GX 339-4, Sco X-1, and Cyg X-2. With high time-resolution…

We present a detailed and systematic investigation of correlated spectral and timing properties of the Z source GX 349+2, using a huge amount (about 40 ks) of good quality data from September 29, 1998 to October 13, 1998, obtained with the…

We investigated the time lags and the evolution of the cross spectra of Z source GX~5-1, observed by the Rossi X-ray Timing Explorer (RXTE), when it is in the horizontal branch oscillations. We showed that the time lags of 3 horizontal…

We report a broadband investigation of the Z-type neutron star (NS) low mass X-ray binary (LMXB) GX 349+2 using AstroSat and NICER. AstroSat observed the source exhibiting large scale variability in its normal branch (NB) /flaring branch…

We report the cross-correlation function studies of a Neutron star low mass X-ray binary, a Z source GX 5-1 using SXT and LAXPC energy bands onboard AstroSat. For the first time, we report the lag between soft (0.8-2.0 keV, SXT) and hard…

We present the results of a systematic investigation of spectral evolution in the Z source GX 349+2, using data obtained during 1998 with Proportional-Counter-Array (PCA) on-board the RXTE satellite. The source traced a extended normal…

We analyze the cross-correlation function between the soft and hard X-rays of atoll source 4U 1735-44 with RXTE data, and find the anti-correlated soft and hard time lags of about hecto-second. On the island state, the observations do not…

We performed the timing and spectral studies of a Z source GX 17+2 observed from Astrosat LAXPC instrument. Cross-Correlation function (CCF) was performed using soft (3-5 keV) and hard (16-40 keV) X -ray bands across the hardness intensity…

Simultaneous X-ray and optical observations of black hole X-ray binaries have shown that the light curves contain multiple correlated and anti-correlated variation components when the objects are in the hard state. In the case of the black…

Sco X-2 (GX 349+2) is a low-mass X-ray binary and Z source. We have analysed 156 ks of Rossi X-ray Timing Explorer data, obtained in 1998 January, on this source. We investigated the fast-time variability as a function of position on the Z…

The scaling relations between the black hole (BH) mass and soft lag properties for both active galactic nuclei (AGNs) and BH X-ray binaries (BHXRBs) suggest the same underlying physical mechanism at work in accreting BH systems spanning a…

Understanding the spectral evolution along the `Z'-shaped track in the hardness-intensity diagram of Z-sources, which are a class of luminous neutron star low-mass X-ray binaries, is crucial to probe accretion processes close to the neutron…