Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Radiation Magnetohydrodynamic Simulations of Sub-Eddington accretion
  Flows in AGN: Origin of Soft X-ray Excess and Rapid Time Variabilities   We investigate the origin of the soft X-ray excess component in Seyfert
galaxies observed when their luminosity exceeds 0.1% of the Eddington
luminosity ($L_{\mathrm{Edd}}$). The evolution of a dense blob in radiatively
inefficient accretion flow (RIAF) is simulated by applying a radiation
magnetohydrodynamic code, CANS+R. When the accretion rate onto a
$10^7M_{\odot}$ black hole exceeds 10% of the Eddington accretion rate ($\dot
M_{\rm Edd}=L_{\rm Edd}/c^2$, where $c$ is the speed of light)}, the dense blob
shrinks vertically because of radiative cooling and forms a Thomson thick,
relatively cool ($\sim10^{7-8}$ K) region. The cool region coexists with the
optically thin, hot ($T\sim10^{11}~\mathrm{K}$) RIAF near the black hole. The
cool disk is responsible for the soft X-ray emission, while hard X-rays are
emitted from the hot inner accretion flow. The soft X-ray emitting region
coexists with the optically thin, hot ($T \sim 10^{11}~\mathrm{K}$),
radiatively inefficient accretion flow (RIAF) near the black hole. Such a
hybrid structure of hot and cool accretion flows is consistent with the
observations of both hard and soft X-ray emissions from `changing-look' active
galactic nuclei (CLAGN). Furthermore, we find that quasi-periodic oscillations
(QPOs) are excited in the soft X-ray emitting region. These oscillations can be
the origin of rapid X-ray time variabilities observed in CLAGN.

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The categories of this paper are: nucl-ex
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The categories of this paper are: adap-org
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The categories of this paper are: bayes-an
33
The categories of this paper are: plasm-ph
20
The categories of this paper are: acc-phys
9
The categories of this paper are: nlin
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The categories of this paper are: q-alg
37
The categories of this paper are: supr-con
35
The categories of this paper are: mtrl-th
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The categories of this paper are: q-fin
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The categories of this paper are: nucl-th
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The categories of this paper are: hep-th
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The categories of this paper are: econ
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The categories of this paper are: physics
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The categories of this paper are: quant-ph
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The categories of this paper are: math