Correlation of γ-ray flux and molecular hydrogen column densities in the Galactic plane

Abstract

Results on cosmic gamma rays have been taken with data, available for the first time, on the distribution of molecular hydrogen over a significant region of the Galactic plane, to study the distribution of cosmic rays in the Galaxy. It is found that there is strong evidence for a lower cosmic-ray intensity in the outer Galaxy, suggestive of a Galactic origin for the particles.