Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: TeV Gamma Rays from BL Lac Objects due to Synchrotron Radiation of
  Extremely High Energy Protons   One of remarkable features of the gamma ray blazar Markarian 501 is the
reported shape of the TeV spectrum, which during strong flares of the source
remains essentially stable despite dramatic variations of the absolute
gamma-ray flux. I argue that this (to a large extent unexpected) behavior of
the source could be explained assuming that the TeV gamma-ray emission is a
result of synchrotron radiation of extremely high energy protons in highly
magnetized compact regions of the jet.

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The categories of this paper are: cond-mat
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The categories of this paper are: alg-geom
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The categories of this paper are: cs
17
The categories of this paper are: q-fin
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The categories of this paper are: q-alg
35
The categories of this paper are: mtrl-th
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The categories of this paper are: stat
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The categories of this paper are: hep-ph
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The categories of this paper are: nlin
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The categories of this paper are: hep-ex
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The categories of this paper are: chem-ph
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The categories of this paper are: chao-dyn
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The categories of this paper are: acc-phys
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The categories of this paper are: math
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The categories of this paper are: adap-org
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The categories of this paper are: hep-th