The Universe Viewed in Gamma-Rays 1 Relativistic and Non-Relativistic Shock Acceleration in Various Objects

The acceleration of energetic charged particles at relativistic and nonrelativistic shock waves plays an important role in powering esztablished and potential cosmic TeV-gamma-ray sources as supernova remnants, jets of active galactic nuclei and gamma-ray bursts. We therefore review some recent results on non-relativistic shock acceleretion and describe the current standing of the theory for relativistic shock acceleration. From the experience with non-relativistic shocks we emphasize that the microphysics of the interaction of plasma wave turbulence with the shock wave is important not only for the resulting momentum spectrum of accelerated particles but also for the shock wave structure itself.