Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: The X-ray continuum time-lags and intrinsic coherence in AGN   We present the results from a systematic analysis of the X-ray continuum
(`hard') time-lags and intrinsic coherence between the $2-4\,\mathrm{keV}$ and
various energy bands in the $0.3-10\,\mathrm{keV}$ range, for ten X-ray bright
and highly variable active galactic nuclei (AGN). We used all available
archival \textit{XMM-Newton} data, and estimated the time-lags following
Epitropakis \& Papadakis (2016). By performing extensive numerical simulations,
we arrived at useful guidelines for computing intrinsic coherence estimates
that are minimally biased, have known errors, and are (approximately) Gaussian
distributed. Owing to the way we estimated the time-lags and intrinsic
coherence, we were able to do a proper model fitting to the data. Regarding the
continuum time-lags, we are able to demonstrate that they have a power-law
dependence on frequency, with a slope of $-1$, and that their amplitude scales
with the logarithm of the light-curve mean-energy ratio. We also find that
their amplitude increases with the square root of the X-ray Eddington ratio.
Regarding the intrinsic coherence, we found that it is approximately constant
at low frequencies. It then decreases exponentially at frequencies higher than
a characteristic `break frequency.' Both the low-frequency constant
intrinsic-coherence value and the break frequency have a logarithmic dependence
on the light-curve mean-energy ratio. Neither the low-frequency constant
intrinsic-coherence value, nor the break frequency exhibit a universal scaling
with either the central black hole mass, or the the X-ray Eddington ratio. Our
results could constrain various theoretical models of AGN X-ray variability.

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The categories of this paper are: chao-dyn
32
The categories of this paper are: atom-ph
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The categories of this paper are: hep-lat
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The categories of this paper are: econ
26
The categories of this paper are: bayes-an
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The categories of this paper are: cmp-lg
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The categories of this paper are: hep-ex
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The categories of this paper are: adap-org
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The categories of this paper are: patt-sol
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The categories of this paper are: stat
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The categories of this paper are: chem-ph
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The categories of this paper are: eess
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The categories of this paper are: cond-mat
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The categories of this paper are: gr-qc
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The categories of this paper are: alg-geom
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The categories of this paper are: physics