We revisit the discovery outburst of the X-ray transient XTE J1550-564 during which relativistic jets were observed in 1998 September, and review the radio images obtained with the Australian Long Baseline Array, and lightcurves obtained with the Mol
onglo Observatory Synthesis Telescope and the Australia Telescope Compact Array. Based on HI spectra, we constrain the source distance to between 3.3 and 4.9 kpc. The radio images, taken some two days apart, show the evolution of an ejection event. The apparent separation velocity of the two outermost ejecta is at least 1.3c and may be as large as 1.9c; when relativistic effects are taken into account, the inferred true velocity is >0.8c. The flux densities appear to peak simultaneously during the outburst, with a rather flat (although still optically thin) spectral index of -0.2.
The INTEGRAL observatory has been (re-)discovering new X-ray sources since the beginning of nominal operations in early 2003. These sources include X-ray binaries, Active Galactic Nuclei, cataclysmic variables, etc. Amongst the X-ray binaries, the tr
ue nature of many of these sources has remained largely elusive, though they seem to make up a population of highly absorbed high-mass X-ray binaries. One of these new sources, IGR J19140+0951, was serendipitously discovered on 2003 Mar 6 during an observation of the galactic microquasar GRS 1915+105. We observed IGR J19140+0951 with UKIRT in order to identify the infrared counterpart. Here we present the H- and K-band spectra. We determined that the companion is a B0.5-type bright supergiant in a wind-fed system, at a distance $la$ 5 kpc.
