Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Diffuse {\gamma}-ray emission from self-confined cosmic rays around
  Galactic sources   The propagation of particles accelerated at supernova remnant shocks and
escaping the parent remnants is likely to proceed in a strongly non-linear
regime, due to the efficient self-generation of Alfv\'en waves excited through
streaming instability near the sources. Depending on the amount of neutral
hydrogen present in the regions around the sites of supernova explosions,
cosmic rays may accumulate an appreciable grammage in the same regions and get
self-confined for non-negligible times, which in turn results in an enhanced
rate of production of secondaries. Here we calculate the contribution to the
diffuse gamma-ray background due to the overlap along lines of sight of several
of these extended halos as due to pion production induced by self-confined
cosmic rays. We find that if the density of neutrals is low, the halos can
account for a substantial fraction of the diffuse emission observed by
Fermi-LAT, depending on the orientation of the line of sight with respect to
the direction of the Galactic centre.

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The categories of this paper are: hep-th
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The categories of this paper are: q-alg
28
The categories of this paper are: alg-geom
35
The categories of this paper are: mtrl-th
25
The categories of this paper are: patt-sol
18
The categories of this paper are: econ
19
The categories of this paper are: eess
29
The categories of this paper are: funct-an
5
The categories of this paper are: gr-qc
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The categories of this paper are: hep-lat
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The categories of this paper are: nucl-th
10
The categories of this paper are: q-bio
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The categories of this paper are: adap-org
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The categories of this paper are: acc-phys
4
The categories of this paper are: cond-mat
24
The categories of this paper are: dg-ga