Neutral iron line in the supernova remnant IC 443 and implications for MeV cosmic rays

Abstract

We report a discovery of bright blob-like enhancements of an Fe I K$\alpha$ line in the northwest and the middle of the supernova remnant (SNR) IC 443. The distribution of the line emission is associated with molecular clouds interacting with the shock front, and is totally different from that of the plasma. The Fe I K$\alpha$ line has a large equivalent width. The most plausible scenario for the origin of the line emission is that the MeV protons accelerated in the shell leak into the molecular clouds and ionize the Fe atoms therein. The observed Fe I K$\alpha$ line intensity is consistent with the prediction of a theoretical model, in which MeV protons are accelerated along with GeV and TeV protons at the SNR.

arXiv comment13 pages, 3 figures, accepted for publication in PASJ

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Cited by in corpus (5)

• Intrusion of MeV-TeV Cosmic-Rays into Molecular Clouds Studied by Ionization, the Neutral Iron Line, and Gamma-Rays
• Multiwavelength studies of G298.6$-$0.0: An old GeV supernova remnant interacting with molecular clouds
• Probing Cosmic Rays with Fe K$\alpha$ Line Structures Generated by Multiple Ionization Process
• Initial state of the recombining plasma in supernova remnant W 28
• Suzaku Observations of Fe K-shell Lines in the Supernova Remnant W51C and Hard X-ray Sources in the Proximity