Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Velocity Profile of the Ionized Disk and the Mass of the Black Hole in
  M87   We present a theoretical model for the ionized disk in M87 which includes
spiral shock waves. The line emission profiles computed from this model at
various positions on the disk are found to be in agreement with the recent
Hubble Space Telescope results. Based on this model, we find that the ionized
disk comprises two-armed giant spiral shock waves which extend from around
$0.1$ arc sec from the center to at least $1$ arc second or more. Our model
requires that the mass of the black hole be $(4 \pm 0.2) \times 10^9 M_\odot$
and the inclination angle to be $(42\pm 2)^{\deg}$. We predict the nature of
the line profiles at many other locations of the disk which could be verified
in future observations.

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The categories of this paper are: hep-ph
5
The categories of this paper are: gr-qc
22
The categories of this paper are: chao-dyn
9
The categories of this paper are: nlin
7
The categories of this paper are: hep-th
12
The categories of this paper are: nucl-th
25
The categories of this paper are: patt-sol
29
The categories of this paper are: funct-an
18
The categories of this paper are: econ
28
The categories of this paper are: alg-geom
21
The categories of this paper are: adap-org
31
The categories of this paper are: ao-sci
34
The categories of this paper are: chem-ph
15
The categories of this paper are: nucl-ex
35
The categories of this paper are: mtrl-th
3
The categories of this paper are: physics