Energetic non-thermal process in galactic objects and ground-based gamma-ray astronomy

Very high energy gamma-rays at TeV energies so far have been detected from pulsar nebula, supernova remnants and active galactic nuclei, and explained by the emission of the electron and positron progenitor. The copious produ ction of the energetic, nonthermal electrons and positrons generally implie s an intense radiation field in the source region and a considerable amount of optical depth for high energy gamma-rays to affect their energy spectru m. The possibility of new classes of gamma-ray sources at TeV energies are also argued in relevance to cosmic rays.