XMM-Newton observations of HESS J1813-178 reveal a composite Supernova remnant

Abstract

We present X-ray and 12CO(J=1-0) observations of the very-high-energy (VHE) γ-ray source HESS J1813-178 with the aim of understanding the origin of the γ-ray emission. We discuss the scenario in which the γ-rays originate in the shell of the SNR, and that in which they originate in the central object, in terms of a time-dependent one-zone leptonic model. We demonstrate, that in order to connect the core X-ray emission to the VHE γ-ray emission electrons have to be accelerated to energies of at least 1 PeV.