Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: The binary black hole scenario for the BL Lacertae object AO 0235+16   Recent analysis of the long term radio lightcurve of the extremely variable
BL Lacertae object AO 0235+16 by Raiteri et al. (2001) have revealed the
presence of recurrent outbursts in this source with a period of ~ 5.7 +/- 0.5
yr. Periodicity analysis of the optical lightcurve also show evidence for a
shorter period. Here we discuss whether such a behavior can be explained by a
binary black hole model where the accretion disk of one of the supermassive
black holes is precessing due to the tidal effects of the companion. We
estimate the mass of the accreting hole and analyze under what constraints onto
the secondary mass and the orbital parameters of the system it is possible to
provide a viable interpretation of the available multiwavelength data.

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The categories of this paper are: chem-ph
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The categories of this paper are: cmp-lg
3
The categories of this paper are: physics
31
The categories of this paper are: ao-sci
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The categories of this paper are: comp-gas
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The categories of this paper are: q-alg
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The categories of this paper are: mtrl-th
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The categories of this paper are: adap-org
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The categories of this paper are: econ
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The categories of this paper are: math-ph
2
The categories of this paper are: math
0
The categories of this paper are: hep-ph
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The categories of this paper are: atom-ph
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The categories of this paper are: alg-geom
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The categories of this paper are: nucl-ex
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The categories of this paper are: hep-lat