Diffuse gamma ray emission : Implications on cosmic ray origin

Abstract

The Compton Gamma Ray Observatory (CGRO) produced the first full sky survery in gamma rays resulting in significantly improved data on the spectral and spatial distribution of diffuse gamma-rays from our galaxy. The intense diffuse gamma-ray emission arising from the Galaxy is understood as primarily arising from the interaction of energetic cosmic rays with the interstellar matter and radiation and is an excellent tool to study cosmic ray spectral characteristics and its distribution within the Galaxy. Comparison of the new data with simple cosmic ray models have led to important conclusions on the spectrum of cosmic-ray protons and electrons. We discuss the current understanding of these models and its implications for a galactic origin of cosmic rays