Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: NGC 4051: Black hole mass and photon index-mass accretion rate
  correlation   We present a discovery of the correlation between the X-ray spectral (photon)
index and mass accretion rate observed in AGN NGC 4051. We analyzed spectral
transition episodes observed in NGC 4051 using XMM/Newton, Suzaku and RXTE. We
applied a scaling technique for a black hole (BH) mass evaluation which uses a
correlation between the photon index and normalization of the seed (disk)
component, which is proportional to a mass accretion rate. We developed an
analytical model that shows the spectral (photon) index of the BH emergent
spectrum undergoes an evolution from lower to higher values depending on
  a mass accretion rate in the accretion disk. We considered Cygnus X-1 and
GRO~J1550-564 as reference sources for which distances, inclination angles and
the BH masses are evaluated by dynamical measurements. Application of the
scaling technique for the photon index-mass accretion rate correlation provides
an estimate of the black hole mass in NGC 4051 to be more than 6x10^5 solar
masses.

26
The categories of this paper are: bayes-an
1
The categories of this paper are: cs
16
The categories of this paper are: stat
14
The categories of this paper are: math-ph
34
The categories of this paper are: chem-ph
3
The categories of this paper are: physics
15
The categories of this paper are: nucl-ex
29
The categories of this paper are: funct-an
32
The categories of this paper are: atom-ph
12
The categories of this paper are: nucl-th
24
The categories of this paper are: dg-ga
10
The categories of this paper are: q-bio
20
The categories of this paper are: acc-phys
4
The categories of this paper are: cond-mat
18
The categories of this paper are: econ
19
The categories of this paper are: eess