On the gamma-ray spectra radiated by protons accelerated in SNR shocks near molecular clouds: The case of SNR RX J1713.7-3946

Abstract

Cosmic rays (CRs) are thought to be accelerated in SNRs. The most favorable situation for proving that the main, hadronic CR component is accelerated there is when CRs interact with dense gases, such as molecular clouds (MC) which surround the SN shock. Here, a new mechanism of spectrum formation in partially ionized gases near SNRs is proposed. Using an analytic model of nonlinear diffusive shock acceleration, we calculate the spectra of protons and estimate the resulting $\gamma$-ray emission occurring when the SNR shock approaches a MC. We show that the spectrum develops a break in the TeV range and that its GeV component is suppressed. These modifications to the standard theory occur because of the proximity of the partially ionized MC-gas and because of the physics of particle and Alfven wave propagation inside the gas. Possible applications of the new spectra to the recent CANGAROO and HESS observations of the SNR RX J1713.7-3946 are discussed.

arXiv comment11 pages 1 figure accepted by ApJL

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Cited by in corpus (29)

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• Cosmic Ray Protons in the Inner Galaxy and the Galactic Center Gamma-Ray Excess
• Study of Nonthermal Emission from SNR RX J1713.7-3946 with Suzaku
• Analytic Solution for Self-regulated Collective Escape of Cosmic Rays from their Acceleration Sites
• Theory of cosmic ray production in the supernova remnant RX J1713.7-3946
• H.E.S.S. observations of RX J1713.7-3946 with improved angular and spectral resolution; evidence for gamma-ray emission extending beyond the X-ray emitting shell
• Escaping the accelerator; how, when and in what numbers do cosmic rays get out of supernova remnants?
• Mechanism for spectral break in cosmic ray proton spectrum from Supernova remnant W44
• Fundamentals of collisionless shocks for astrophysical application, 2. Relativistic shocks
• A joint spectro-imaging analysis of the XMM-Newton and HESS observations of the supernova remnant RX J1713.7-3946
• A cosmic ray current driven instability in partially ionised media
• Discovery of a Radio Supernova Remnant and Non-thermal X-rays Coincident with the TeV Source HESS J1813-178
• Unified model for the gamma-ray emission of supernova remnants
• Neutrinos from galactic sources of cosmic rays with known gamma-ray spectra
• Probing Nearby CR Accelerators and ISM Turbulence with Milagro Hot Spots
• Improved Cosmic-Ray Injection Models and the Galactic Center Gamma-Ray Excess
• Cosmic Ray Acceleration by Supernova Shocks
• A young SNR illuminating nearby Molecular Clouds with cosmic rays
• Dynamics of Mesoscale Magnetic Field in Diffusive Shock Acceleration
• Arguments against a dominantly hadronic origin of the VHE radiation from the supernova remnant RX J1713-3946
• Collisionless shocks in partly ionized plasma with cosmic rays: microphysics of non-thermal components
• Non-Thermal X-ray Emission from the Northwestern Rim of the Galactic Supernova Remnant G266.2-1.2 (RX J0852.0-4622)
• On the mechanism for breaks in the cosmic ray spectrum
• Environmental limits on the non-resonant cosmic-ray current-driven instability
• Method to extract the primary cosmic ray spectrum from very high energy gamma-ray data and its application to SNR RX J1713.7-3946
• Stochastic Acceleration of Cosmic Rays in the Central Molecular Zone of the Galaxy
• Time-dependent shock acceleration of particles. Effect of the time-dependent injection, with application to supernova remnants
• CANGAROO-III observation of TeV gamma rays from the unidentified gamma-ray source HESS J1614-518