Gamma-Ray Emission from Supernova Remnant Interaction with Molecular Clumps

Abstract

Observations of the middle-aged supernova remnants IC 443, W28 and W51C indicate that the brightnesses at GeV and TeV energies are correlated with each other and with regions of molecular clump interaction, but not with the radio synchrotron brightness. We suggest that the radio emission is primarily associated with a radiative shell in the interclump medium of a molecular cloud, while the gamma-ray emission is primarily associated with the interaction of the radiative shell with molecular clumps. The shell interaction produces a high pressure region, so that the gamma-ray luminosity can be approximately reproduced even if shock acceleration of particles is not efficient, provided that energetic particles are trapped in the cooling region. In this model, the spectral shape \ga 2 GeV is determined by the spectrum of cosmic ray protons. Models in which diffusive shock acceleration determines the spectrum tend to underproduce TeV emission because of the limiting particle energy that is attained.

15 pages, ApJ Letters, accepted

References in corpus (4)

• Detection of the Characteristic Pion-Decay Signature in Supernova Remnants
• Parameterization of Gamma, e^+/- and Neutrino Spectra Produced by p-p Interaction in Astronomical Environment
• Discovery of 35 New Supernova Remnants in the Inner Galaxy
• Isolated X-ray -- infrared sources in the region of interaction of the supernova remnant IC 443 with a molecular cloud

Cited by in corpus (6)

• Modeling Bright Gamma-ray and Radio Emission at Fast Cloud Shocks
• TeV cosmic ray nuclei acceleration in shell-type supernova remnants with hard $\gamma$-ray spectra
• Time-dependent Diffusive Shock Acceleration in Slow Supernova Remnant Shocks
• SNR G39.2-0.3, an Hadronic Cosmic Rays Accelerator
• A new look at the integrated radio/microwave continuum spectrum of Galactic supernova remnant IC443
• Limits on compression of cosmic rays in supernova remnants