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.

arXiv comment15 pages, ApJ Letters, accepted

References in corpus (22)

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• A 7mm line survey of the shocked and disrupted molecular gas towards the W28 field TeV gamma-ray sources
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Cited by in corpus (16)

• Modeling Bright Gamma-ray and Radio Emission at Fast Cloud Shocks
• Is molecular cloud turbulence driven by external supernova explosions?
• Numerical simulations of supernova remnants in turbulent molecular clouds
• 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
• GeV γ-ray Emission Detected by Fermi-LAT Probably Associated with the Thermal Composite Supernova Remnant Kesteven 41 in a Molecular Environment
• NuSTAR Detection of a Hard X-ray Source in the Supernova Remnant - Molecular Cloud Interaction Site of IC 443
• Post-adiabatic supernova remnants in an interstellar magnetic field: oblique shocks and non-uniform environment
• SNR G39.2-0.3, an Hadronic Cosmic Rays Accelerator
• Gamma-ray emission from middle-aged supernova remnants interacting with molecular clouds: the challenge for current models
• Interaction between Molecular Clouds and MeV-TeV Cosmic-ray Protons Escaped from Supernova Remnants
• Electron Acceleration in Middle-age Shell-type $\gamma$-Ray Supernova Remnants
• The role of the diffusive protons in the gamma-ray emission of supernova remnant RX J1713.7$-$3946 --- a two-zone model
• FERMI-LAT Observations of Supernova Remnant G5.7-0.1, Believed to be Interacting with Molecular Clouds
• A new look at the integrated radio/microwave continuum spectrum of Galactic supernova remnant IC443
• Limits on compression of cosmic rays in supernova remnants