Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Quasi-periodic oscillations in the $\gamma$-ray light curves of bright
  active galactic nuclei   The detection of quasi-periodic oscillations (QPOs) in the light curves of
active galactic nuclei (AGNs) can provide insights on the physics of the
super-massive black-holes (SMBHs) powering these systems, and could represent a
signature of the existence of SMBH binaries, setting fundamental constraints on
SMBH evolution in the Universe. Identification of long term QPOs, with periods
of the order of months to years, is particularly challenging and can only be
achieved via all-sky monitoring instruments that can provide unbiased,
continuous light-curves of astrophysical objects. The Fermi-LAT satellite,
thanks to its monitoring observing strategy, is an ideal instrument to reach
such a goal, and we aim to identify QPOs in the $\gamma$-ray light-curves of
the brightest AGNs within the Fermi-LAT catalog. We analyze the light curves of
the thirty-five brightest Fermi-LAT AGNs, including data from the beginning of
the Fermi mission (August 2008) to April 2020, and energies from 100 MeV to 300
GeV. Two time binnings are investigated, 7 and 30 days. The search for
quasi-periodic features is then performed using the continuous wavelet
transform. The significance of the result is tested via Monte Carlo simulations
of artificial light curves with the same power spectral density and probability
distribution function as the original light curves. We identify thirty quasars
with candidate QPOs. We confirm several QPO candidates discussed in the
literature: PKS 2247-131, B2 1520+31, PKS 0426-380, PKS 0537-441, S5 0716+714,
Mrk 421, PKS 1424-418, PG 1553+113, Mrk 501 and PKS 2155-304. The most
significant QPO (> 4$\sigma$ in the global wavelet spectrum, with a period of
about 1100 days) is observed in the quasar S5 1044+71, and is reported here for
the first time.

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The categories of this paper are: quant-ph
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The categories of this paper are: alg-geom
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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: mtrl-th
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The categories of this paper are: hep-lat
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The categories of this paper are: funct-an
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The categories of this paper are: econ
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The categories of this paper are: plasm-ph
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The categories of this paper are: cs
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The categories of this paper are: gr-qc
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The categories of this paper are: adap-org
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The categories of this paper are: hep-th
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The categories of this paper are: math
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The categories of this paper are: chem-ph
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The categories of this paper are: acc-phys