COS-B gamma-ray sources and interstellar gas in the first galactic quadrant. Caravane collaboration for the COS-B satellite.

The consequences are considered for the high-energy gamma-ray sources of the recently established correlation between the intensity above 300 MeV, and tracers of atomic and molecular gas, in the first quadrant of the Galaxy. Using a likelihood method on the complete set of COS-B data, it is shown that there are point-like gamma-ray sources which do not have counterparts in the gas data. They may be due to localized enhancements of the cosmic-ray density or, alternatively, may be quite independent of the gas. There are two sources near the edges of the Cygnus X complex and one near M17, all of which correspond to COS-B sources in the 2CG catalog, but whose positions and fluxes the present work is better able to define. Three other 2CG sources appear to be explained above 300 MeV by the gas alone. Two transient or variable sources have also been observed.