Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: VSOP monitoring of the compact BL Lac object AO 0235+164   In 1999, the highly compact and variable BL Lac object AO 0235+164 was
identified as the highest brightness temperature active galactic nucleus
observed with the VLBI Space Observatory Programme (VSOP), with T_B > 5.8 x
10^{13} K. The sub-milliarcsecond radio structure of this source has been
studied with dual-frequency (1.6 and 5 GHz), polarization-sensitive VSOP
observations during 2001 and 2002. Here we present the results of this
monitoring campaign. At the time of these observations, the source was weakly
polarized and characterized by a radio core that is clearly resolved on
space-ground baselines.

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The categories of this paper are: cond-mat
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The categories of this paper are: adap-org
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The categories of this paper are: hep-ex
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The categories of this paper are: hep-ph
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The categories of this paper are: ao-sci
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The categories of this paper are: plasm-ph
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The categories of this paper are: eess
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The categories of this paper are: mtrl-th
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The categories of this paper are: solv-int
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The categories of this paper are: cmp-lg
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The categories of this paper are: comp-gas
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The categories of this paper are: chao-dyn
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The categories of this paper are: nlin
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The categories of this paper are: physics
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The categories of this paper are: quant-ph
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The categories of this paper are: hep-lat