BATSE observations of transient hard X-ray sources

Abstract
Many transient sources have been detected and monitored by the Burst and Transient Source Experiment (BATSE) since launch using the Earth occultation technique. These include x‐ray novae, pulsars, and other galactic sources. We present preliminary results of the temporal and spectral characteristics for seven transients which are potentially black hole candidates due to their hard spectra, lack of pulsations, and the appearance of their light curves. The seven transients are: GRO J0422+32 (X‐Ray Nova Persei 1992), GS/GRS 1124−68 (Nova Muscae 1991), GX 339−4, 4U 1543−47, GRS 1915+105, GRO J1719−24=GRS 1716−249 (X‐Ray Nova Ophiuchi 1993) and GRS 1009−45 (X‐Ray Nova Velorum 1993). We search for signatures in their spectra and light curves which are found to be common to black hole candidates. Generally, these objects appear to divide into two classes based on their light curves: the x‐ray nova‐type transients with fast rise and approximately exponential decay, and the slow rising, long duration bright transients.