Gamma Rays from Molecular Clouds

Abstract

I discuss the spectral features of pi-0 decay gamma-radiation from clouds/targets located in proximity of relatively young proton accelerators, and speculate that such ``accelerator+target'' systems in our Galaxy can be responsible for a subset of unidentified EGRET sources. Also, I argue that the recent observations of high energy gamma-rays from the Orion complex contain evidence that the level of the ``sea'' of galactic cosmic rays may differ significantly from the flux and the spectrum of local (directly detected) particles.