Related papers: The 2015 hard-state only outburst of GS 1354-64
We study in detail the evolution of the 2015 outburst of GS 1354-64 (BW Cir) at optical, UV and X-ray wavelengths using Faulkes Telescope South/LCOGT, SMARTS and Swift. The outburst was found to stay in the hard X-ray state, albeit being…
We present the results of Rossi X-ray Timing Explorer observations of GS 1354-644 during a modest outburst in 1997-1998. The source is one of a handful of black hole X-ray transients that are confirmed to be recurrent in X-rays. A 1987…
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 Galactic transient black hole GS 1354-64 recently showed a new outburst, which has been continuously monitored by {\it MAXI}, {\it NuSTAR} and {\it Insight-HXMT} missions. The ongoing $2025-26$ outburst shows a slow-rise with an unusual…
Black hole transients during bright outbursts show distinct changes of their spectral and variability properties as they evolve during an outburst, that are interpreted as evidence for changes in the accretion flow and X-ray emitting…
We present observations of the 1997 outburst of the X-ray transient GS 1354-64 (BW Cir) at X-ray, optical and, for the first time, radio wavelengths; this includes upper limits to the linear and circular polarisation of the radio data. The…
We perform broadband ($0.7-100$ keV) spectral analysis of five hard state observations of the low-mass back hole X-ray binary GX~339--4 taken by AstroSat during the rising phase of three outbursts from $2019$ to $2022$. We find that the…
We perform a comprehensive timing and broadband spectral analysis using an AstroSat observation of the low-mass black hole X-ray binary H~1743--322 during 2017 outburst. Additionally, we use two Swift/XRT observations, one of which is…
We report on a campaign of X-ray and soft gamma-ray observations of the black hole candidate H 1743-322 (also named IGR J17464-3213), performed with the RXTE, INTEGRAL and Swift satellites. The source was observed during a short outburst…
We present the results of a NuSTAR study of the dynamically confirmed stellar-mass black hole GS 1354-645. The source was observed during its 2015 "hard" state outburst; we concentrate on spectra from two relatively bright phases. In the…
The black hole candidate Swift J1753.5-0127 went into outburst in 2005 June. Rather than fade into quiescence as most black-hole-candidate transients do, it has remained in a low hard spectral state for most of the $\sim$ 9 years after…
We have performed a joint spectral and timing analysis of the outburst of GRS 1739-278 in 2014 based on Swift and INTEGRAL data. We show that during this outburst the system exhibited both intermediate states: hard and soft. Peaks of…
The well-known black hole X-ray binary GRS 1915+105 is a unique source in the sense that it cannot be classified within the standard picture of black hole binary states. In this work we study archival XMM-Newton observations taken between…
We report on the spectroscopic analysis of the black hole binary GX 339-4 during its recent 2017-2018 outburst, observed simultaneously by the Swift and NuSTAR observatories. Although during this particular outburst the source failed to…
We present Swift observations of the black hole X-ray transient, GRO J1655-40, during the recent outburst. With its multiwavelength capabilities and flexible scheduling, Swift is extremely well-suited for monitoring the spectral evolution…
The extent of the accretion disk in the low/hard state of stellar mass black hole X-ray binaries remains an open question. There are some evidence suggesting that the inner accretion disk is truncated and replaced by a hot flow, while the…
The black hole low-mass X-ray binary (LMXB) candidate IGR J17091-3624 experienced a hard-state-only outburst in 2025. In this paper, we show that IXPE detected a series of intermittent X-ray dips, spanning a total interval of ~1 day.…
We have analysed RXTE archival data to study the aperiodic variability of the black-hole binary GRO J1655-40 during the hard state of the 2005 outburst. We computed the 0.008-64 Hz power spectral density during the rise and decay of the…
While the standard X-ray variability of black hole X-ray binaries (BHXBs) is stochastic and noisy, there are two known BHXBs that exhibit exotic `heartbeat'-like variability in their light curves: GRS 1915+105 and IGR J17091-3624. In 2022,…
Four persistent (Cygnus X-1, GX 339-4, GRS 1758-258 and 1E 1740.7-2942) and three transient (GS 2023+38, GRO J0422+32 and GS 1354-64) black hole X-ray binary systems have been extensively observed at radio wavelengths during extended…