The radial distribution of galactic gamma rays. IV. The whole galaxy.
Strong, A. W.; Grenier, I. A.; Hermsen, W.; Pollock, A. M. T.; Lebrun, F.; Bloemen, J. B. G. M.; Thaddeus, P.; Nyman, L. -Å.; Dame, T. M.
Germany, United States, Netherlands, France
Abstract
The correlation between diffuse galactic γ-rays and gas tracers is studied using the final COS-B database and H I and CO surveys covering the entire galactic plane. A good quantitative fit to the γ-rays is obtained, with a small gradient in the γ-ray emissivity per hydrogen atom. The average ratio of H2 column density to integrated CO temperature is determined. The corresponding mass of molecular hydrogen in the inner Galaxy, derived using both 1st and 4th quadarants, is 1.0×109M_sun;.