Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Hard X-ray and Gamma-ray Emission Induced by Ultra-High Energy Protons
  in Cluster Accretion Shocks and their Detectability   Protons can be plausibly accelerated to $\sim 10^{18}$-$10^{19}$ eV in strong
accretion shocks surrounding massive clusters of galaxies. Such protons
efficiently produce very high energy pairs through interactions with the CMB,
which then radiate synchrotron and inverse Compton emission with hard spectra,
peaking respectively in hard X-rays and TeV gamma-rays. We discuss the
prospects for detecting this emission from nearby clusters with current and
future facilities such as HESS and NeXT, which should provide a clear signature
of ultra-high energy proton acceleration and an important probe of magnetic
fields in the outermost regions of clusters.

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The categories of this paper are: solv-int
13
The categories of this paper are: quant-ph
1
The categories of this paper are: cs
28
The categories of this paper are: alg-geom
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The categories of this paper are: eess
12
The categories of this paper are: nucl-th
30
The categories of this paper are: q-alg
33
The categories of this paper are: plasm-ph
24
The categories of this paper are: dg-ga
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The categories of this paper are: chao-dyn
14
The categories of this paper are: math-ph
3
The categories of this paper are: physics
32
The categories of this paper are: atom-ph
29
The categories of this paper are: funct-an
0
The categories of this paper are: hep-ph
4
The categories of this paper are: cond-mat