Gamma Ray Astronomy

Recent observations have marked the transition of gamma ray astronomy from a discovery phase to an exploratory one. This has been the result of the development of a number of very sophisticated sensitive telescopes and the opportunity to place them on space platforms. A survey of the instruments developed for this research is given together with a brief summary of the current status of the observational results. These include the studies of galactic gamma ray emission, the diffuse, presumably extragalactic, gamma radiation and localized gamma ray sources. The study of the spatial distribution of galactic gamma radiation is beginning to provide a new means for the study of galactic structure and dynamics. The diffuse emission may provide evidence of gamma ray emission in the cosmological past, although improved observations must be obtained before the picture can be clarified. The study of localized sources has shown NP0532, the Crab radio pulsar, to be a gamma ray pulsar also and strong emission from Vela may be due to supernova produced cosmic rays interacting with the remnant gas.