Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Effects of Homogeneous Plasma on Strong Gravitational Lensing of Kerr
  Black Holes   Considering a Kerr black hole surrounded by the homogenous unmagnetised
plasma medium, we study the strong gravitational lensing on the equatorial
plane of the Kerr black hole. We find that the presence of the uniform plasma
increases the photon-sphere radius $r_{ps}$, the coefficient $\bar{a},\bar{b}$,
the angular position of the relativistic images $\theta_{\infty}$, the
deflection angle $\alpha(\theta)$ and the angular separation $s$. However the
relative magnitudes $r_m$ decrease in presence of the uniform plasma medium. It
is also shown that the impact of the uniform plasma on the effect of strong
gravitational become smaller as the spin of the Kerr black increace in prograde
orbit($a>0$). Especially, for the extreme black hole(a=0.5), the effect of
strong gravitational lensing in homogenous plasma medium is the same as the
case in vacuum for the prograde orbit.

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The categories of this paper are: alg-geom
25
The categories of this paper are: patt-sol
37
The categories of this paper are: supr-con
17
The categories of this paper are: q-fin
33
The categories of this paper are: plasm-ph
15
The categories of this paper are: nucl-ex
18
The categories of this paper are: econ
21
The categories of this paper are: adap-org
12
The categories of this paper are: nucl-th
16
The categories of this paper are: stat
6
The categories of this paper are: astro-ph
20
The categories of this paper are: acc-phys
0
The categories of this paper are: hep-ph
3
The categories of this paper are: physics
35
The categories of this paper are: mtrl-th
31
The categories of this paper are: ao-sci