Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Excess GeV radiation and cosmic ray origin   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.

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The categories of this paper are: gr-qc
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The categories of this paper are: hep-th
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The categories of this paper are: adap-org
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The categories of this paper are: chao-dyn
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The categories of this paper are: q-bio
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The categories of this paper are: funct-an
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The categories of this paper are: acc-phys
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The categories of this paper are: q-fin
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The categories of this paper are: atom-ph
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The categories of this paper are: plasm-ph
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The categories of this paper are: physics
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The categories of this paper are: hep-lat
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The categories of this paper are: patt-sol
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The categories of this paper are: econ
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The categories of this paper are: cmp-lg
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The categories of this paper are: nlin