Related papers: State Transitions of GRS 1739$-$278 in the 2014 Ou…
We investigate the behaviour of the accretion discs in the outbursts of the low-mass black-hole X-ray binaries (BHXRB), an overview of which we have presented previously. Almost all of the systems in which there are sufficient observations…
To understand the bursting behavior of the microquasar GRS 1915+105, we calculate time evolution of a luminous, optically thick accretion disk around a stellar mass black hole undergoing limit-cycle oscillations between the high- and low-…
We studied X-ray reverberation lags in the BHXRB GX 339-4 at the end of the 2014-2015 outburst. We analysed data from a XMM-Newton campaign covering the end of the transition from the soft to the hard state, and the decrease of luminosity…
The neutron star binary SAX J1747.0-2853, located in the Galactic Center region at about 0.5 deg from Sgr A* and at a distance of 9 kpc, has been observed in outburst four times (1998, 1999, 2000 and 2001) by BeppoSAX and RossiXTE. At the…
Based on data from the SWIFT, INTEGRAL, MAXI/ISS orbital observatories, and the ground-based RTT-150 telescope, we have investigated the broadband (from the optical to the hard X-ray bands) spectrum of the X-ray nova MAXI J1828-249 and its…
We report BeppoSAX and optical observations of the black hole candidate GX 339-4 during its X-ray `off' state in 1999. The broad-band (0.8-50 keV) X-ray emission can be fitted by a single power law with spectral index, \alpha ~1.6. The…
We report the quasi-simultaneous INTEGRAL, SWIFT, and NuSTAR observations showing spectral state transitions in the neutron star low mass X-ray binary 1RXS J180408.9-342058 during its 2015 outburst. We present results of the analysis of…
Here we report on Swift and Suzaku observations near the end of an outburst from the black hole transient 4U 1630-47 and Chandra observations when the source was in quiescence. 4U 1630-47 made a transition from a soft state to the hard…
MAXI J1813-095 is an X-ray transient discovered during an outburst in 2018. We report on X-ray and optical observations obtained during this event, which indicate that the source is a new low-mass X-ray binary. The outburst lasted ~70 d and…
The black hole candidate (BHC) X-ray transient 4U 1630-47 continuously produced strong X-ray emission for over 2 years during 2002-2004. We use observations made with the Rossi X-ray Timing Explorer (RXTE) to study the source throughout the…
Constraining the accretion flow geometry of black hole binaries in outburst is complicated by the inability of simplified multi-colour disc models to distinguish between changes in the inner disc radius and alterations to the emergent…
We report the results of observations with the Rossi X-ray Timing Explorer of the black-hole candidate GX 339-4 during the state transition of 1998. We find that both the X-ray spectrum and the characteristic of the time variability after…
The black-hole X-ray binary transient GRO J1655-40 underwent an outburst beginning in early 2005. We present the results of our multi-wavelength observational campaign to study the early outburst spectral and temporal evolution, which…
Due to observational challenges our knowledge of low-level accretion flows around neutron stars is limited. We present Nustar, Swift and Chandra observations of the low-mass X-ray binary IGR J17062-6143, which has been persistently…
The black hole candidate X-ray transient XTE J1817-330 was observed by the Swift satellite over 160 days of its 2006 outburst with the XRT and UVOT instruments. At the start of the observations, the XRT spectra show that the 0.6-10 keV…
The key aspect of the very successful truncated disc model for the low/hard X-ray spectral state in black hole binaries is that the geometrically thin disc recedes back from the last stable orbit at the transition to this state. This has…
IGR J17091-3624 is the only black hole X-ray binary candidate, aside from the well-studied black hole system GRS 1915+105, observed to exhibit a wide range of structured variability patterns in its light curves. In 2025, the source…
The black hole X-ray binary 4U 1755$-$338 underwent an outburst in 2020 after 25 years of quiescence. The comprehensive spectral analysis revealed that the system has a low interstellar neutral hydrogen column density of $0.34\pm0.01…
We report results from a broadband spectral analysis of the low mass X-ray binary MXB 1658-298 with the Swift/XRT and NuSTAR observations made during its 2015-2017 outburst. The source showed different spectral states and accretion rates…
In this work, we present a spectral and temporal analysis of {\it Swift}/XRT and {\it NuSTAR} observations of GRS 1716--249 during its recent 2016--2017 outburst. This low mass X-ray binary underwent an extraordinary outburst after a long…