We report the discovery of a near-infrared (nIR) counterpart to the persistent neutron-star low-mass X-ray binary 4U 1705−440, at a location consistent with its recently determined Chandra X-ray position. The nIR source is highly variable, with Ks-band magnitudes varying between 15.2 and 17.3 and additional Jand H-band observations revealing color variations. A comparison with contemporaneous X...

We discuss the putative class of B[e] X-ray binaries, with reference to currently identified candidate systems, focusing on CI Cam and the newly identified class of highly obscured hard X-ray sources detected by INTEGRAL. We suggest that such a class will likely consist of two types of object in which the B[e] phenomenon is (i) intrinsic to the mass donor or (ii) a result of binarity. Finally, ...

I suggest that there are two classes of ultraluminous X–ray sources (ULXs), corresponding to super–Eddington mass inflow in two situations: (a) thermal–timescale mass transfer in high–mass X–ray binaries, and (b) long–lasting transient outbursts in low–mass X–ray binaries. These two classes are exemplified by SS433 and microquasars like GRS 1915+105 respectively. The observed ULX population is ...

The observed luminosity distributions of X-ray sources indicate the presence of several populations of X-ray binaries in the nearby galaxies. Each population has its formation and evolutionary history, depending on the host environment. The features seen in the log N(>S) – log S curves for different types of galaxies and for different galactic components can be reproduced by a birth-death model...

We combine our close binary population number synthesis code with the formation mechanism of X-radiation in young supernova remnants and in high mass X-ray binaries, to predict the hard X-ray luminosity emitted by starbursts. We demonstrate that the impact of interacting binaries is substantial. Therefore, observations of hard X-rays with energies larger than 2 keV of starburst regions may high...

We present a catalogue of 107 point-like X–ray sources derived from a systematic analysis of all the ROSAT PSPC observations of the galactic center region performed in 1992–1993. Besides SgrA*, the massive black hole at the galactic center, 41 X–ray sources have been positionally associated with already classified objects. Twenty are identified with foreground stars and five with known Low Mass...