Gamma astronomy from space and from ground

Abstract

Ground based observations has come of age with the advent of the Whipple imaging telescope 10 years ago. The decade that followed has been a period of consolidation, with several detectors of performance comparable to that of the Whipple, mostly HEGRA and CAT in the Northern hemisphere and Cangaroo and Mark-6 in the South. A few important results have been obtained, but the number of firmly established sources remain quite scarce. EGRET has collected an impressive amount of data mostly concerning the blazars, but it has left many questions open, and many of the observed sources remain unidentified. The new decade will bring in major progress, with the new satellites AGILE and GLAST and with large arrays of telescopes in both hemispheres. In the same time, new ground based techniques are under study either for better angular coverage or lower energy threshold. Finally, new sites are setting in, which have to find their part to play in this context.