The galactic microquasar GRS1915+105 has been in a continuous state of outburst since 1992, over 20 times longer than any other black hole X-ray transient. Assuming that the outburst is powered via accretion of an irradiated gaseous disc, we calculate how the predicted outburst duration varies according to the efficiency of the self-irradiation mechanism. At least one current model leads to the...

4U1630−47 is a black-hole X-ray transient with one of the shortest recurrence times. Despite its regular outburst behaviour little is known about this source. Only recently has attention to this system increased. I discuss there the basic known (X-ray) properties of 4U 1630−47 and report on X-ray and radio observations obtained during its recent outburst, starting in 1998 February. These observ...