12-20 July 2017
Asia/Seoul timezone
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BEXCO - Room E(106/107)

[GA052] Hard Cosmic Ray Sea in the Galactic Center: a consistent interpretation of H.E.S.S. and Fermi-LAT gamma-ray data


  • Dario GRASSO

Primary authors



We present a novel interpretation of the gamma-ray diffuse emission measured by H.E.S.S. in the Galactic Center (GC) and the Central Molecular Zone (CMZ) regions. We start with a data driven analysis based on PASS8 Fermi-LAT data which allows to extend down to few GeV the spectra measured by H.E.S.S. and to infer the primary Cosmic Ray (CR) radial distribution above 100 GeV. We compare those results with a CR transport model assuming a spatial dependent scaling of the diffusion coefficient with rigidity. Such a behaviour allows to reproduce the radial dependence of the CR spectral index recently inferred from Fermi-LAT measurements in the inner Galactic plane. We find that, in this scenario, the bulk of the CMZ emission can be naturally explained by the interaction of the diffuse, steady-state Galactic CR sea interacting with the gas present in the CMZ. Under these conditions, the evidence of a GC Pevatron is significantly weaker than that found adopting a conventional (softer) CR sea. (Based mainly on arXiv:1702.01124 , accepted for publication in Phys. Rev. Lett. )