Low and medium energy galactic gamma-ray observations

Abstract

Observation of 0.2-100 MeV diffuse gamma radiation emitted from the Galaxy can provide information on the intensities of 5-50 MeV/nucleon cosmic-rays and 50 MeV electrons in interstellar space. Recent measurements of gamma-rays emitted from the galactic center region provide evidence for a diffuse continuum between 10 and 100 MeV. The intensities of the recently reported nuclear line gamma rays, also observed in the direction of the galactic center, require the presence of intense fluxes of low-energy cosmic-rays in the inner Galaxy if the gamma-rays are produced on a galactic scale. Current detection techniques for 0.1-100 MeV gamma-ray measurements are summarized and their capabilities for measuring the diffuse galactic emission are evaluated.