OVERVIEW OF THE 1ST RESULTS FROM EGRET

The Energetic Gamma Ray Experiment Telescope (EGRET), one of four instruments carried on the Compton Gamma Ray Observatory, is capable of detecting photons in the energy range from approximately 20 MeV to 30 GeV. After a period of about one month for test and calibration, a 15-month all sky survey was begun. The June 11, 1992 solar flare was observed in gamma rays with energies from the threshold of detection to energies over 1 GeV. Detailed time histories and energy spectra have been obtained for the Crab and Vela pulsars, with one of the Vela pulses being quite sharp, approximately 2% of the total period. Several gamma ray bursts have been recorded. In particular, the one on May 3, 1991 was seen in the spark chamber system of EGRET, allowing a position to be determined. The galactic plane diffuse gamma ray emission has been observed in many regions of the plane, and the galactic center region spectrum has been compared to that expected for cosmic rays interacting with matter and photons and found to agree well. The quasar 3C 279, which has a z of 0.538, was seen in high energy gamma rays in both June and October, 1992. It is time variable on times as short as 2 days, and has a hard energy spectrum. The quasars 3C 273, PKS 0208-512, 4C 38.41, PKS 0528+134, and 0836+710 also have been tentatively identified. 4C 38.41, with a z of 1.8, has a hard gamma ray energy spectrum.