Theory of cosmic ray and γ-ray production in the supernova remnant RX J0852.0-4622

Aims: The properties of the Galactic supernova remnant (SNR) RX J0852.0-4622 are theoretically analysed.
Methods: An explicitly time-dependent, nonlinear kinetic model of cosmic ray (CR) acceleration in SNRs is used to describe the properties of SNR RX J0852.0-4622, the accelerated CRs, and the nonthermal emission. The source is assumed to be at a distance of ≈ 1 kpc in the wind bubble of a massive progenitor star. An estimate of the thermal X-ray flux in this configuration is given.
Results: We find that the overall synchrotron spectrum of RX J0852.0-4622 as well as the filamentary structures in hard X-rays lead to an amplified magnetic field B > 100 ~μG in the SNR interior. This implies that the leptonic very high energy (VHE) γ-ray emission is suppressed, and that the VHE γ-rays are hadronically dominated. The energy spectrum of protons produced over the lifetime of the remnant until now may well reach “knee” energies. The derived γ-ray morphology is consistent with the HESS measurements. The amount of energy in energetic particles corresponds to about 35% of the hydrodynamic explosion energy. A remaining uncertainty concerns the thermal X-ray flux at 1 keV. A rough estimate, which is possibly not quite appropriate for the assumed wind bubble configuration, is found to be higher than the nonthermal flux at this energy.
Conclusions: It is concluded that this SNR expanding into the wind bubble of a massive star in a dense gas environment can be a hadronic γ-ray source that is consistent with all existing multiwavelength constraints, except possibly the thermal X-ray emission.

Now at Institut für Astronomie und Astrophysik, Universität Tübingen, Sand 1, 72076 Tübingen, Germany.