Cosmic gamma rays from the Orion molecular cloud complex

Abstract

COS B results on the fluxes of cosmic gamma rays from the A and B clouds in the Orion complex have been used to study the extent to which known astronomical objects in the clouds are significant sources of cosmic-ray particles (sources such as T-Tauri stars, Herbig-Haro objects and radio sources). The method uses the ratio of the gamma -ray fluxes from the two clouds and is thus insensitive to systematic errors in the estimate of the masses of the clouds. It is found that there is no evidence favouring production of cosmic rays within the clouds to any significant extent; the clouds are probably inert in this respect and simply irradiated by the ambient cosmic-ray flux.