characteristics of bursts observed by the smm gamma-ray spectrometerThe Gamma Ray Spectrometer (GRS) on the SMM completed close to 10 years of highly successful operation when the spacecraft reentered the atmosphere on December 2, 1989. During this period the GRS detected 177 events above 300 keV which have been classified as cosmic gamma-ray bursts. A catalog of these events is in preparation which will include time profiles and spectra for all events. Visual inspection of the spectra indicates that emission typically extends into the MeV range, without any evidence for a high-energy cutoff; 17 of these events are also observed above 10 MeV. We find no convincing evidence for line-like emission features in any of the time-integrated spectra.
Share, G. H. (U.S. Navy E.O. Hulburt Center for Space Research, Washington, United States)
Messina, D. C. (SFA, Inc. Landover, MD, United States)
Iadicicco, A. (U.S. Navy E.O. Hulburt Center for Space Research, Washington, United States)
Matz, S. M. (Northwestern Univ. Evanston, IL, United States)
Rieger, E. (Max-Planck-Inst. for Extraterrestrial Physics Garching, Germany)
Forrest, D. J. (New Hampshire Univ. Durham, United States)