Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Search for gamma-rays above 10 TeV from Markarian 421 in a high state
  with the CANGAROO-II telescope   A preliminary result from Markarian 421 observations in the energy region
above 10 TeV with the CANGAROO-II 10 m telescope is presented. In January 2001,
the HEGRA group reported that Markarian 421 had become very active, with flux
levels up to 4 times that of the Crab Nebula. As a result, we observed Mkn 421
during six nights from January 24th to February 1st, and four nights from March
1st to 4th. Observations were carried out using the very large zenith angle
technique ($\sim$70 degree) and the energy threshold is estimated from Monte
Carlo simulations to be around 10 TeV. We have detected gamma-ray emission in
this energy range.

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The categories of this paper are: nlin
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The categories of this paper are: funct-an
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The categories of this paper are: dg-ga
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The categories of this paper are: chao-dyn
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The categories of this paper are: adap-org
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The categories of this paper are: eess
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The categories of this paper are: stat
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The categories of this paper are: q-bio
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The categories of this paper are: atom-ph
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The categories of this paper are: cs
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The categories of this paper are: plasm-ph
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The categories of this paper are: cond-mat
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The categories of this paper are: q-fin
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The categories of this paper are: hep-ex
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The categories of this paper are: q-alg
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The categories of this paper are: quant-ph