Characteristics of the periodic hard X-ray sources discovered during the Prognoz-9 experiment: The results of a further analysis

During the Prognoz-9 experiment, we searched for periodic sources in the hard X-ray range (10-200 keV), No periodicities were detected during the observations of regions offset from the Galactic plane and the Galactic-"anticenter" region, A further analysis of the data refined the list of observed periodic sources in the Galactic-center region with periods of hours and days. In addition to the previously detected periodicities-152 h (Nova Ophiuchi 1977), 98 h, 82 h (4U 1700-37), 69 h, 62 h, 13.3 h, 9.36 h, 8.15 h (Cen X-4), 4.35 h (4U 1755-33), and 3.45 h-we found new periodic sources: 8.04, 4.38, and 1.47 h. The mean phase profiles (light curves) in various energy bands were constructed for all the observed periodicities. The mean phase profiles for most of the observed periodic sources differ in shape: from harmonic and purely "eclipsing" profiles, Evidence was obtained for the presence of peculiar phase features in some of the light curves.