AbstractA strong, confirmed gamma-ray burst was observed by a background-monitoring scintillation detector on the Spacelab 2 mission. The peak of the burst was at 00:56:38 UT on August 5, 1985. The large size of the detector allowed observations up to 16 MeV with high efficiency. A high data rate provided time-resolved observations over the energy range from 60 keV to 16 MeV, limited only by counting statistics.The burst was dominated by a single peak, ∼2 s wide, with softer, lower-level emission lasting ∼20 s> after the main peak. There was no evidence for time structure less than ∼0.2 s anywhere in the burst in any energy range. These characteristics are similar to a sizeable fraction (∼25%) of burst seen in the Konus catalog and we suggest that they are distinct from the more complex, “spiky” bursts and may have a different emission mechanism.In the energy range from ∼560 keV to ∼10 meV, the burst peaks ∼0.3 s before the peak at lower energies. Radiation in the energy range ∼10 to ∼16 MeV was detected at a confidence level of >96%, about 3 s before the lower energy radiation with roughly the same pulse width. This radiation is not detected during the main part of the burst. The energy of this burst in the range above 1 MeV is a significant fraction of the total burst energy, confirming the earlier SMM results.
AbstractWe report on the preliminary analysis of fast temporal fluctuations observed in hard X-ray bursts, as recorded by the Burst and Transient Source Experiment (BATSE) on the Compton Gamma Ray Observatory.
AbstractData from the burst and transient source experiment (BATSE) onboard the Compton Gamma-Ray Observatory (CGRO) have been used to set upper limits on emission in the 20–1800 keV energy range from the collision of Comet Shoemaker–Levy 9 with Jupiter. For an impulsive event of 1 sec duration we place a 4 sigma upper limit on the equivalent isotropic energy release of 5 × 1020ergs in the 20–50 keV energy band. The upper limit on steady emission observed during the week of the collision is 2 × 1019erg/sec (20–50 keV). We discuss the implications of these observations for impact effects on the jovian atmosphere.
AbstractThe Energetic X-ray Imaging Survey Telescope (EXIST), under study to be the Black Hole Finder Probe in NASA’s Beyond Einstein Program, would image the sky every 95 min in the energy range 10–600 keV. Although the main scientific objectives of EXIST are the systematic, all-sky survey of heavily obscured AGNs and gamma-ray bursts, there is a substantial capability of EXIST for the observation of transient and persistent hard X-ray lines from several astrophysical sources.