Fermi Gamma-ray Space Telescope

Cosmic Rays Escape from Supernova Remnants in a Multiphase Interstellar Medium

Soonyoung Roh
Shu-ichiro Inutsuka, Tsuyoshi Inoue

Abstract:

Supernova remnants (SNRs) are one of the most powerful astrophysical event and are thought to be the dominant source of Galactic cosmic rays (CRs). A recent report by Funk et al. (2013) has shown an unequivocal signature of pion-decay in the gamma-ray spectra of SNRs. This provides strong evidence that high energy protons are accelerated in SNRs. On the other hand, Fukui et al. (2012) showed that pion decay from protons dominates in emission from SNR RX J1713 based on the spatial correlation of gamma-rays and molecular line emission. The actual gamma-ray emission from pion decay should depend on the diffusion of CRs in a multiphase interstellar medium with molecular clouds (Inoue et al. 2012). In order to quantitatively describe the diffusion of high energy CRs from acceleration sites, we have performed test particle numerical simulations using a three-dimensional magnetohydrodynamics (MHD) simulation data provided by Inoue et al. (2012). We analyze a realistic diffusion coefficient of cosmic rays in simulated SNRs, and discuss about superdiffusive process (Lazarian & Yan, 2014) for describing the CRs propagation and acceleration in Supernova Remnants.