We present a set of face-on models of the radiative transfer of stellar light in exponential discs, taking into account absorption and multiple scattering (diffusion) by dust. Attention has been directed towards the effects on the observable photometric properties of different distributions of stars and dust perpendicular to the galactic plane. A

We propose to detect and resolve the candidate radio counterpart of an ultraluminous X-ray source (ULX) at the outskirts of NGC 1313. This ULX is surrounded by a huge ionized nebula. We expect to find a corresponding synchrotron radio bubble, possibly inflated by a jet from the black hole, with additional core emission. By combining radio, optical

We report on recent radio observations of the newly-detected accreting millisecond X-ray pulsar, IGR J17511-3057 (ATels #2196, #2197, #2198, #2199, #2215, #2216, #2220, #2221). We used the Very Large Array (VLA) to observe the source under observing program AM971. The array was in its relatively compact 'C' and 'DNC' configurations, and the

We present the discovery of optical/X-ray flux correlations on rapid time-scales in the low/hard state of the Galactic black hole GX339-4. The source had recently emerged from outburst and was associated with a relatively faint counterpart with mag V ~ 17. The optical [Very Large Telescope (VLT)/ULTRACAM] and X-ray (Rossi X-ray Timing Explorer)

A rapid timing analysis of Very Large Telescope (VLT)/ULTRACAM (optical) and RXTE (X-ray) observations of the Galactic black hole binary GX339-4 in the low/hard, post-outburst state of 2007 June is presented. The optical light curves in the r',g' and u' filters show slow (~20s) quasi-periodic variability. Upon this is superposed fast flaring

We report the detection of orbital decay in the 12.75-minute, detached binary white dwarf (WD) SDSS J065133.338+284423.37 (hereafter J0651). Our photometric observations over a 13 month baseline constrain the orbital period to 765.206543(55) s and indicate that the orbit is decreasing at a rate of (- 9.8 ± 2.8) × 10-12 s s-1 (or -0.31 ± 0.09 ms yr