Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Blazar observations above 60 GeV: the Influence of CELESTE's Energy
  Scale on the Study of Flares and Spectra   The CELESTE atmospheric Cherenkov detector ran until June 2004. It has
observed the blazars Mrk 421, 1ES 1426+428 and Mrk 501. We significantly
improved our understanding of the atmosphere using a LIDAR, and of the optical
throughput of the detector using stellar photometry. The new data analysis
provides better background rejection. We present our light curve for Mrk 421
for the 2002-2004 season and a comparison with X-ray data and the 2004
observation of 1ES 1426+428. The new analysis will allow a more sensitive
search for a signal from Mrk 501.

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The categories of this paper are: dg-ga
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The categories of this paper are: cs
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The categories of this paper are: math-ph
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The categories of this paper are: physics
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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: supr-con
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The categories of this paper are: gr-qc
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The categories of this paper are: econ
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The categories of this paper are: hep-ph
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The categories of this paper are: hep-lat
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The categories of this paper are: alg-geom
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The categories of this paper are: quant-ph
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The categories of this paper are: stat
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The categories of this paper are: q-fin
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The categories of this paper are: hep-ex