Diffuse cosmic rays shining in the Galactic center: A novel interpretation of H.E.S.S. and Fermi-LAT -ray data
Feb 3, 2017
5 pages
Published in:
- Phys.Rev.Lett. 119 (2017) 3, 031101
- Published: Jul 17, 2017
e-Print:
- 1702.01124 [astro-ph.HE]
Report number:
- CERN-TH-2017-034
View in:
Citations per year
Abstract: (APS)
We present a novel interpretation of the γ-ray diffuse emission measured by Fermi-LAT and H.E.S.S. in the Galactic center (GC) region and the Galactic ridge (GR). In the first part we perform a data-driven analysis based on PASS8 Fermi-LAT data: We extend down to a few GeV the spectra measured by H.E.S.S. and infer the primary cosmic-ray (CR) radial distribution between 0.1 and 3 TeV. In the second part we adopt a CR transport model based on a position-dependent diffusion coefficient. Such behavior reproduces the radial dependence of the CR spectral index recently inferred from the Fermi-LAT observations. We find that the bulk of the GR emission can be naturally explained by the interaction of the diffuse steady-state Galactic CR sea with the gas present in the central molecular zone. Although we confirm the presence of a residual radial-dependent emission associated with a central source, the relevance of the large-scale diffuse component prevents to claim a solid evidence of GC pevatrons.Note:
- 5 pages, 3 figures, accepted for publication in Physical Review Letters
- cosmic radiation: primary
- galaxy
- GLAST
- HESS
- position dependence
- transport theory
- power spectrum
- background
- diffusion
- gamma ray
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Figures(3)
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