Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: The condensation of the corona for the correlation between the hard
  X-ray photon index $\Gamma$ and the reflection scaling factor $\Re$ in active
  galactic nuclei   Observationally, it is found that there is a strong correlation between the
hard X-ray photon index $\Gamma$ and the Compton reflection scaling factor
$\Re$ in active galactic nuclei. In this paper, we propose that the
$\Gamma-\Re$ correlation can be explained within the framework of the
condensation of the hot corona onto the cold accretion disc around a
supermassive black hole. In the model, it is presumed that, initially, a
vertically extended hot gas (corona) is supplied to the central supermassive
black hole by capturing the interstellar medium and stellar wind. In this
scenario, when the initial mass accretion rate $\dot M/ \dot M_{\rm Edd}
\gtrsim 0.01$, at a critical radius $r_{\rm d}$, part of the hot gas begins to
condense onto the equatorial disc plane of the black hole, forming an inner
cold accretion disc. Then the matter is accreted in the form of the disc-corona
structure extending down to the innermost stable circular orbits of the black
hole. The size of the inner disc is determined by the initial mass accretion
rate. With the increase of the initial mass accretion rate, the size of the
inner disc increases, which results in both the increase of the Compton
reflection scaling factor $\Re$ and the increase of the hard X-ray photon index
$\Gamma$. By comparing with a sample of Seyfert galaxies with well-fitted X-ray
spectra, it is found that our model can roughly explain the observations.
Finally, we discuss the possibility to apply our model to high mass X-ray
binaries, which are believed to be fueled by the hot wind from the companion
star.

11
The categories of this paper are: hep-lat
14
The categories of this paper are: math-ph
29
The categories of this paper are: funct-an
9
The categories of this paper are: nlin
4
The categories of this paper are: cond-mat
7
The categories of this paper are: hep-th
12
The categories of this paper are: nucl-th
27
The categories of this paper are: comp-gas
28
The categories of this paper are: alg-geom
19
The categories of this paper are: eess
23
The categories of this paper are: solv-int
10
The categories of this paper are: q-bio
36
The categories of this paper are: cmp-lg
18
The categories of this paper are: econ
16
The categories of this paper are: stat
13
The categories of this paper are: quant-ph