Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Detection of a quasi-periodic oscillation in gamma-ray light curve of
  the high redshift blazar B2 1520+31   We detected a possible quasi-periodic oscillation (QPO) of ~ 71 days in the
0.1 -- 300 GeV gamma-ray Fermi-LAT light curve of the high redshift flat
spectrum radio quasar B2 1520+31. We identify and confirm that quasi-period by
Lomb Scargle periodogram (LSP), and weighted wavelet z-transform (WWZ)
analyses. Using this QPO period, and assuming it originates from accretion-disc
fluctuations at the innermost stable circular orbit, we estimate the central
supermassive black hole mass to range between ~ 5.4 * 10$^{9}$ M$_{\odot}$ for
a non-rotating black hole and ~ 6.0 * 10$^{10}$ M$_{\odot}$ for a maximally
rotating black hole. We briefly discuss other possible radio-loud active
galactic nuclei emission models capable of producing a gamma-ray QPO of such a
period in a blazar.

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The categories of this paper are: econ
33
The categories of this paper are: plasm-ph
14
The categories of this paper are: math-ph
13
The categories of this paper are: quant-ph
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The categories of this paper are: chao-dyn
31
The categories of this paper are: ao-sci
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The categories of this paper are: acc-phys
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The categories of this paper are: dg-ga
0
The categories of this paper are: hep-ph
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The categories of this paper are: cmp-lg
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The categories of this paper are: q-alg
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The categories of this paper are: comp-gas
2
The categories of this paper are: math
9
The categories of this paper are: nlin
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The categories of this paper are: solv-int
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The categories of this paper are: q-fin