Excess GeV radiation and cosmic ray origin
arXiv:astro-ph/0108321 · doi:10.1051/0004-6361:20011125
Abstract
Recent EGRET observations of the diffuse Galactic gamma-ray emission reveal a spectrum which is incompatible with the assumption that the cosmic ray spectra measured locally hold throughout the Galaxy: the spectrum above 1 GeV, where the emission is supposedly dominated by pi^0-decay, is harder than that derived from the local cosmic ray proton spectrum. We demonstrate that in case of a SNR origin of cosmic ray nucleons part of this gamma-ray excess may be attributed to the dispersion of the spectral indices in these objects. In global averages, as are gamma-ray line-of-sight integrals, this dispersion leads to a positive curvature in the composite spectrum, and hence to modified pi^0-decay gamma-ray spectra.
accepted for publication in Astronomy and Astrophysics
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Cited by in corpus (15)
- Cosmic-ray propagation and interactions in the Galaxy
- Indirect signals from light neutralinos in supersymmetric models without gaugino mass unification
- Understanding TeV-band cosmic-ray anisotropy
- Cosmic ray spectral hardening due to dispersion in the source injection spectra
- Diffractive Interaction and Scaling Violation in pp->pi^0 Interaction and GeV Excess in Galactic Diffuse Gamma-Ray Spectrum of EGRET
- Cosmic-ray propagation properties for an origin in SNRs
- No evidence yet for hadronic TeV gamma-ray emission from SNR RX J1713.7-3946
- Adiabatic compression and indirect detection of supersymmetric dark matter
- Spectral softening in core-collapse supernova remnant expanding inside wind-blown bubble
- Gamma-ray lines from cosmic-ray interactions with interstellar dust grains
- A comparison between direct and indirect dark matter search
- Gamma-ray detection from neutralino annihilation in non--universal SUGRA scenarios
- Particle acceleration, escape and non-thermal emission from core-collapse supernovae inside non-identical wind-blown bubbles
- Unresolved Unidentified Source Contribution to the Gamma-ray Background
- Gamma-ray Spectra due to Cosmic-ray Interactions with Dense Gas Clouds