On the nature of the galactic gamma-ray sources.

Available data constrain possible models of the gamma-ray point (or pointlike) sources found by COS B. Apart from the pulsars (Crab, Vela) and possibly the quasar 3C 273, which are "compact" objects, and which have been identified at other photon energies, there are some 20-odd other sources with no accepted or acceptable counterpart, as yet. This class of "gamma-ray objects" may be due to cosmic ray interaction with aggregates of diffuse interstellar matter - i.e., clouds. The constraints on this hypothesis, both observationally and theoretically, are discussed for various scenarios.