Positions and evidence for a steady component for X-ray burst sources

During observations of the galactic center region during February and March 1976 in an experiment on the satellite Ariel V x-ray fluxes were observed from two sources near the sources MXB 1730-335 and MXB 1728-34. The observations represented integrations over periods of about one satellite orbit (100 min). The intensity of the source near MXB 1730-335 corresponded to an energy of approximately 3 x 10-9 erg/cm2/sec over the range 1.5 to 20 keV. This intensity is consistent with the reported burst activity, together with a steady non-burst component. An improved determination was obtained for this source. In the case of the second source each burst lasted for a few seconds and the mean integrated flux associated with the bursts was at least two orders of magnitude lower than for MXB 1730-335, although the intensity integrated over one orbit was similar, although somewhat more variable. If the source represents flux from MXB 1728-34 it must be due to a non-burst background emission. (U.K.)