Hadronic gamma-rays from RX J1713.7-3946?

Abstract

RX J1713.7-3946 is a key object to check the supernova remnant paradigm of the origin of Galactic cosmic rays. While the origin of its gamma-ray emission (hadronic versus leptonic) is still debated, the hard spectrum at GeV energies reported by the Fermi collaboration is generally interpreted as a strong argument in favour of a leptonic scenario. On the contrary, we show that hadronic interactions can naturally explain the gamma-ray spectrum if gas clumps are present in the supernova remnant shell. The absence of thermal X-rays from the remnant fits well within this scenario.