Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Effects of Magnetic Coupling on Radiation from Accretion Disc around a
  Kerr Black Hole   The effects of magnetic coupling (MC) process on the inner edge of the disc
are discussed in detail. It is shown that the inner edge can deviate from the
innermost stable circular orbit (ISCO) due to the magnetic transfer of energy
and angular momentum between a Kerr black hole (BH) and its surrounding
accretion disc. It turns out that the inner edge could move inward and outward
for the BH spin $a_{*}$ being greater and less than 0.3594, respectively. The
MC effects on disc radiation are discussed based on the displaced inner edge. A
very steep emissivity can be provided by the MC process, which is consistent
with the observation of MCG-6-30-15. In addition, the BH spins of GRO J1655-40
and GRS 1915+105 are detected by X-ray continuum fitting based on this model.

17
The categories of this paper are: q-fin
33
The categories of this paper are: plasm-ph
5
The categories of this paper are: gr-qc
11
The categories of this paper are: hep-lat
22
The categories of this paper are: chao-dyn
31
The categories of this paper are: ao-sci
35
The categories of this paper are: mtrl-th
10
The categories of this paper are: q-bio
24
The categories of this paper are: dg-ga
8
The categories of this paper are: hep-ex
12
The categories of this paper are: nucl-th
1
The categories of this paper are: cs
2
The categories of this paper are: math
3
The categories of this paper are: physics
13
The categories of this paper are: quant-ph
19
The categories of this paper are: eess