REVIEW OF GRANAT OBSERVATIONS OF GAMMA-RAY BURSTS

The GRANAT observatory was launched into a high apogee orbit on 1 Dece mber, 1989. Three instruments onboard GRANAT - PHEBUS, WATCH and SIGMA . are able to detect gamma-ray bursts in a very broad energy range fro m 6 keV up to 100 MeV. Over 250 gamma-ray bursts were detected. We dis cuss the results of the observations of the time histories and spectra l evolution of the detected events provided by the different instrumen ts in different energy ranges. Short Gamma-Ray Bursts (< 2 s) have 10 ms structure in their time histories. They have harder energy spectra than the long (> 2 s) events. Evidence of the existence of four differ ently behaving componenents in gamma-ray burst spectra is discussed. S tatistical properties of the gamma-ray burst sources based on the 5 ye ars of observations with (similar to 10(-6) erg/cm(2)) sensitivity as well as the results of high sensitivity (similar to 10(-8) erg/cm(2)) search for Gamma-Ray Bursts within the SIGMA telescope field of view a re reviewed.