Hard X-ray observations of X-ray Nova Ophiuchi 1993 (GRS 1716-249) with GRANAT/SIGMA.

The results of observations of X-ray Nova Ophiuchi 1993 (GRS 1716-249) in hard X-ray/low γ-ray energy domain with the SIGMA telescope aboard the GRANAT observatory are reported. The hard X-ray emission from the source has been observed by SIGMA during a bright flare in 1993 and one year later - during the reappearance of the source in 1994. Combining the SIGMA data with results of quasi contemporaneous TTM (MIR-KVANT) observations the spectral behavior of the source is studied in the 2-400 keV energy band. Both in 1993 and 1994 the broad-band spectrum of GRS 1716-249 was quite similar to the low (hard) state spectrum of Cyg X-1, although subtle spectral variations, possibly correlated with the luminosity, were clearly detected.