High resolution gamma-ray astronomy in the energy range 0.05 to 10 mev

Abstract

An analysis of the detection properties of an actively shielded 86cm (^3) germanium detector is given. Results are presented of observations of the Crab Nebula, its associated pulsar PSR0531+21, the Seyfert galaxy NGC1275, and the COS B source 2CG195+5. Evidence is presented for gamma-ray line emission from the Crab at energies of 404.7 and 1049.8 keV with intensities at the top of the atmosphere of (7.2 ± 2.1) x 10(^-3) and (2.03 ± 0.46) X 10(^-2) s (^-1) respectively. A line at 78.9 keV has also been detected at the 4.1o level which shows time variability. The peak flux at the top of the atmosphere was measured to be (1.1 ± 0.26) x 10(^-2) photons cm"(^-2)s(^-1) .We report the detection of redshifted annihilation radiation from the type II Seyfert galaxy, NGC 1275.The measured flux at the top of the atmosphere is (7.1 ± 2.2) x 10(^-3)photons cm(^-2)s(^-1),