New evidence on the galactic cosmic ray distribution from COS-B gamma-ray data.

The end of the COS-B mission and the near completion of the first analysis stage of its data base prompts a critical review of the work done on the topic of the diffuse gamma-ray emission from the IS galactic gas. The local (<1 kpc) ISM features are mapped for the first time in gamma-ray light, requiring a CR intensity similar to that observed at the Sun. On a wider galactic scale, however, and especially in the anticenter direction it now seems that the COS-B gamma-ray data do not reveal the expected radial decrease of the proton CR component, as expected from the standard galactic origin theory.