X-Ray Outburst of Aquila X-1 (4U 1908+00)

M. Oda and the Hakucho Team, University of Tokyo, report that, following the discovery of an optical outburst of Aql X-1 by B. Margon (cf. IAUC 3478), extensive observations were made by Hakucho. From May 20 to 22 the x-ray intensity at 3-6 keV remained at ~ 0.12 Crab, and the intensity then declined to ~ 0.08, 0.04 and < 0.02 Crab on May 24, 26 and 28, respectively. During the observations two intense x-ray bursts were recorded, on May 23d20h53m and 24d23h52m UT. The peak intensity of the bursts was ~ 2.5 Crab in the 3-6 keV range. The location of the source of these bursts is consistent with that of the source of the persistent emission, thus excluding the possibility that the bursts came from the nearby x-ray burster MXB1905+000.