Origin of 6.4 keV Line Emission from Molecular Clouds in the Galactic Center

Abstract

Abstract We analyze the 6.4 keV line and continuum emission from the molecular cloud Sgr B2 and the source HESS J1745$-$303, which is supposed to be a complex of molecular gas. From the HESS results it follows that Sgr A$^\ast$ is a source of high energy protons, which penetrate into molecular clouds producing there a TeV gamma-ray flux. We present arguments that Sgr A$^\ast$ may also produce a flux of subrelativistic protons which generate the 6.4 keV line and bremsstrahlung continuum emission from the clouds.