The galactic gamma-ray source population

A procedure has been developed to estimate the contribution to the galactic gamma-ray emission by discrete sources under the assumption that the sources are distributed spatially like the total emission, but without regard to the nature of the individual sources. In particular, an analytical method is developed for calculating the fraction of the total galactic gamma-ray emission above 70 MeV that originates in the COS B-like sources. The COS B longitude flux profile for energies between 70 MeV and 5 GeV is unfolded to give the galactocentric emissivity distribution. It is found that about 25-30 percent of the total gamma-ray emission of the galaxy is due to COS B-like sources, representing a total luminosity of about 2.5 x 10 to the 38th ergs/s. These results are found to be relatively independent of the luminosity function of the source population for average source luminosities below 10 to the 37th ergs/s.