COS-B gamma-ray measurements, cosmic rays and the local interstellar medium
Caraveo, P. A.; Bignami, G. F.; Strong, A. W.; Hermsen, W.; Lebrun, F.; Buccheri, R.; Kanbach, G.; Mayer-Hasselwander, H. A.; Paul, J. A.; Wills, R. D.
France, Italy, Netherlands, United Kingdom
Abstract
A study of the relation between galaxy counts and gamma rays measured by the COS-B satellite clearly shows that there exists a bidimensional correlation between these quantities. Though the 21 cm measurements are more accurate than galaxy counts they show a weaker correlation with gamma rays. A significant fraction of the local gas in molecular form, linked to the dust, can account for this situation: gamma rays and galaxy counts being total gas tracers. The gamma-ray emissivity per hydrogen atom is derived leading to an estimate of the spectrum of the cosmic-ray electrons contributing to the gamma-ray emission through bremsstrahlung interactions.