An Overview and Perspectives of the CANGAROO Observations

Tadashi Kifune

University of Tokyo

Recent observation of high energy gamma rays has revealed that the sky is bright to have more than 200 point-like sources at GeV energies, as discovered by EGRET insturment of Compton Gamma Ray Observatory, with several sources at even higher energies of TeV. The current status of very high energy gamma ray astronomy (in about 1 TeV region) is described by using as example results of CANGAROO (Collaboration of Australia and Nippon for a GAmma Ray Observatory in the Outback). Gamma rays at TeV energies, emitted through inverse Compton effect of electrons or $\pi ^0$ decay from proton interaction, provide direct evidence on energetic non-thermal processes of the Universe, as well as environmental features, such as the strength of magnetic field in the emission region, for the non-thermal processes.