Published online by Cambridge University Press: 14 August 2015
It has long been expected that gamma-ray astronomy will visualize the mysterious cosmic-ray (CR) sources. Indeed, on the basis of COS-B observations, it has been proposed that CR acceleration within the Rho Oph cloud complex (ROCC) is required to account for its gamma-ray luminosity (Cassé and Paul, 1980, herein after CP, Bignami and Morfill, 1980). However, Issa et al. (1980) have suggested that the size of the ROCC has been underestimated by a factor ≃2, and that the cloud mass is a factor ≃ 4 higher than given by Myers et al. (1978), making unnecessary CR acceleration and trapping in the cloud interior.