Theory of cosmic ray production in the supernova remnant RX J1713.7-3946

¹ Yu. G. Shafer Institute of Cosmophysical Research and Aeronomy, 31 Lenin Ave., 677980 Yakutsk, Russia e-mail: berezhko@ikfia.ysn.ru
² Max Planck Institut für Kernphysik, Postfach 103980, 69029 Heidelberg, Germany e-mail: Heinrich.Voelk@mpi-hd.mpg.de

Received: 26 November 2005
Accepted: 30 January 2006

Abstract

Aims.A nonlinear kinetic theory of cosmic ray (CR) acceleration in supernova remnants (SNRs) is employed to investigate the properties of SNR RX J1713.7-3946.

Methods.Observations of the nonthermal radio and X-ray emission spectra as well as the HESS measurements of the very high energy γ-ray  emission are used to constrain the astronomical and the particle acceleration parameters of the system.

Results.Under the assumptions that RX J1713.7-3946 was a core collapse supernova (SN) of type II/Ib with a massive progenitor, has an age of  yr and is at a distance of  kpc, the theory gives indeed a consistent description for all the existing observational data. Specifically it is shown that an efficient production of nuclear CRs, leading to strong shock modification, and a large downstream magnetic field strength  μG can reproduce in detail the observed synchrotron emission from radio to X-ray frequencies together with the γ-ray   spectral characteristics as observed by the HESS telescopes. Small-scale filamentary structures observed in nonthermal X-rays provide empirical confirmation for the field amplification scenario which leads to a strong depression of the inverse Compton and Bremsstrahlung fluxes. Going beyond that and using a semi-empirical relation for young SNRs between the resulting CR pressure and the amplified magnetic field energy upstream of the outer SN shock as well as a moderate upper bound for the mechanical explosion energy, it is possible to also demonstrate the actual need for a considerable shock modification in RX J1713.7-3946. It is consistent with RX J1713.7-3946 being an efficient source of nuclear cosmic rays.