Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Discovery of a ~5 day characteristic timescale in the Kepler power
  spectrum of Zw 229-15   We present time series analyses of the full Kepler dataset of Zw 229-15. This
Kepler light curve --- with a baseline greater than three years, composed of
virtually continuous, evenly sampled 30-minute measurements --- is
unprecedented in its quality and precision. We utilize two methods of power
spectral analysis to investigate the optical variability and search for
evidence of a bend frequency associated with a characteristic optical
variability timescale. Each method yields similar results. The first
interpolates across data gaps to use the standard Fourier periodogram. The
second, using the CARMA-based time-domain modeling technique of Kelly et al.
(2014), does not need evenly-sampled data. Both methods find excess power at
high frequencies that may be due to Kepler instrumental effects. More
importantly both also show strong bends ({\Delta}{\alpha} ~ 2) at timescales of
~5 days, a feature similar to those seen in the X-ray PSDs of AGN but never
before in the optical. This observed ~5 day timescale may be associated with
one of several physical processes potentially responsible for the variability.
A plausible association could be made with light-crossing, dynamical or thermal
timescales, depending on the assumed value of the accretion disk size and on
unobserved disk parameters such as {\alpha} and H/R. This timescale is not
consistent with the viscous timescale, which would be years in a ~10^7 Solar
mass AGN such as Zw 229-15. However there must be a second bend on long (>~1
year) timescales, and that feature could be associated with the viscous
timescale.

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The categories of this paper are: cmp-lg
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The categories of this paper are: nlin
11
The categories of this paper are: hep-lat
4
The categories of this paper are: cond-mat
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The categories of this paper are: bayes-an
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The categories of this paper are: econ
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The categories of this paper are: chao-dyn
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The categories of this paper are: q-alg
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The categories of this paper are: hep-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: math-ph
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The categories of this paper are: q-fin
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The categories of this paper are: adap-org
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The categories of this paper are: stat
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The categories of this paper are: mtrl-th