4U 1608-52

M. Oda, Institute of Space and Aeronautical Science, University of Tokyo, communicates: "The Hakucho observing team (Japanese X-Ray Observatory, CORSA-B) has discovered intense x-ray bursts from a source in Norma located within an error circle of radius 0o.5 centered on the position of 4U 1608-52 (Fabbiano et al. 1978, Astrophys. J. 221, L49). Two burst events recorded on Apr. 9d08h29m41s and 16d18h09m51s UT are similar in size (intensity ~ 8 x Crab in the 2-12-keV range) and have a shape typical of a burster. The burst size is consistent with that previously recorded by Vela satellites (Belian et al. 1976, Astrophs. J. 206, L135). A bright and apparently steady x-ray source at 0.5 Crab has been present prior to and through the bursts within the same error circle and is most probably associated with the bursts. 4U 1608-52 has been previously identified with a reddened star of magnitude 18.2 (Grindlay and Liller 1978, Astrophys. J. 220, L127)." L. Kaluzienski and S. Holt, Goddard Space Flight Center, report the detection of an outburst from the region (error circle radius ~ 2o) centered on the position of the recurrent transient 4U 1608-52 with the Ariel 5 all-sky monitor. The flare commenced on Apr. 9 with a flux (3-6 keV) of ~ 0.2 Crab recorded at that time. A rapid brightening to a level of ~ 0.6 Crab was observed during Apr. 12-15, and the source was still bright when last observed on Apr. 22. It is noted that the last flare from 4U 1608-52 occurred in late January (IAUC 3328) and that both the latter event and the recent outburst of Aql X-1 (IAUC 3342) have been subsequently confirmed with the solid-state spectrometer aboard the Einstein Observatory HEAO 2.