Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: The distribution of the coronal temperature in Seyfert 1 galaxies   The Active Galactic Nuclei (AGN) produce copious amounts of X-rays through
the corona that is the hot gas that lies close to the accretion disk. The
temperature of the corona can be accurately determined by the cut-off signature
in the X-ray spectrum. Owing to the large temperatures of the corona,
observations well above 10 keV are necessary. Here, we explore the NuSTAR
observations of 118 Gehrels/Swift selected Seyfert 1 AGN. We model the spectrum
using a single power-law with an exponential cut-off modified by neutral and
ionised absorption as well as a reflection component. We find secure spectral
cut-off estimates in 62 sources while for the remaining ones we derive only
lower limits. The mean value is 103 keV with a skewed distribution towards
large energies with large dispersion. When we consider the lower limits using
survival analysis techniques, the mean cut-off energy becomes significantly
larger, about 200 keV. Because of various limitations (e.g. limited spectral
passband, photon statistics, model degeneracies) we perform extensive
simulations to explore the underlying spectral cut-off distribution. We find
that an intrinsic spectral cut-off distribution which has a Maxwell-Boltzmann
shape with a mean value in the range of 160 - 200 keV can reproduce
sufficiently well the observations. Finally, our spectral analysis places very
stringent constraints on both the photon index (Gamma=1.77+/-0.01) as well as
on the reflection component (R=0.69+/-0.04) of the Seyfert 1 population. From
the values of the spectral cut-off and the photon-index we deduce that the mean
optical depth of the AGN corona is approximately tau=1.82+/-0.14 and its mean
temperature approximately kT=65+/-10 keV.

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The categories of this paper are: plasm-ph
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The categories of this paper are: alg-geom
27
The categories of this paper are: comp-gas
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The categories of this paper are: cmp-lg
7
The categories of this paper are: hep-th
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The categories of this paper are: funct-an
5
The categories of this paper are: gr-qc
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The categories of this paper are: solv-int
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The categories of this paper are: bayes-an
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The categories of this paper are: mtrl-th
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The categories of this paper are: q-fin
0
The categories of this paper are: hep-ph
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The categories of this paper are: hep-ex
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The categories of this paper are: nlin
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The categories of this paper are: ao-sci
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The categories of this paper are: cs