Query : 2001A&A...377.1056B

2001A&A...377.1056B - Astronomy and Astrophysics, volume 377, 1056-1062 (2001/10-3)

Excess GeV radiation and cosmic ray origin.


Abstract (from CDS):

Particle acceleration at supernova remnant (SNR) shock waves is regarded as the most probable mechanism for providing Galactic cosmic rays at energies below 1015 eV. The Galactic cosmic ray hadron component would in this picture result from the injection of relativistic particles from many SNRs. It is well known that the superposition of individual power law source spectra with dispersion in the spectral index value, which behaviour is observed in the synchrotron radio spectra of shell SNR, displays a positive curvature in the total spectrum and in particular shows a hardening at higher energies. Recent observations made with the EGRET instrument on the Compton Gamma-Ray Observatory of the diffuse Galactic γ-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 1GeV, where the emission is supposedly dominated by π0-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 γ-ray excess may be attributed to the dispersion of the spectral indices in these objects. In global averages, as are γ-ray line-of-sight integrals, this dispersion leads to a positive curvature in the composite spectrum, and hence to modified π0-decay γ-ray spectra.

Abstract Copyright:

Journal keyword(s): ISM: cosmic rays - ISM: supernova remnants - gamma rays: theory

Simbad objects: 4

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Number of rows : 4
N Identifier Otype ICRS (J2000)
ICRS (J2000)
Mag U Mag B Mag V Mag R Mag I Sp type #ref
1850 - 2023
1 ESO 134-11 HII 14 40 29 -62 38.7           ~ 551 1
2 SNR G315.0-02.3 SNR 14 43 00 -62 30.0           ~ 360 1
3 NAME Lupus SN SNR 15 02 22.1 -42 05 49           ~ 1297 1
4 SNR G347.3-00.5 SNR 17 12 27 -39 41.2     12.27     ~ 694 1

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