Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Subsonic accretion and dynamical friction for a black hole moving
  through a self-interacting scalar dark matter cloud   We investigate the flow around a black hole moving through a cloud of
self-interacting scalar dark matter. We focus on the large scalar mass limit,
with quartic self-interactions, and on the subsonic regime. We show how the
scalar field behaves as a perfect gas of adiabatic index $\gamma_{\rm ad}=2$ at
large radii while the accretion rate is governed by the relativistic regime
close to the Schwarzschild radius. We obtain analytical results thanks to
large-radius expansions, which are also related to the small-scale relativistic
accretion rate. We find that the accretion rate is greater than for
collisionless particles, by a factor $c/c_s \gg 1$, but smaller than for a
perfect gas, by a factor $c_s/c \ll 1$, where $c_s$ is the speed of sound. The
dynamical friction is smaller than for a perfect gas, by the same factor $c_s/c
\ll 1$, and also smaller than Chandrasekhar's result for collisionless
particles, by a factor $c_s/(cC)$, where $C$ is the Coulomb logarithm. It is
also smaller than for fuzzy dark matter, by a factor $v_0/c \ll 1$.

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The categories of this paper are: funct-an
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The categories of this paper are: chem-ph
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The categories of this paper are: dg-ga
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The categories of this paper are: q-alg
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The categories of this paper are: quant-ph
19
The categories of this paper are: eess
18
The categories of this paper are: econ
32
The categories of this paper are: atom-ph
15
The categories of this paper are: nucl-ex
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The categories of this paper are: patt-sol
1
The categories of this paper are: cs
3
The categories of this paper are: physics
2
The categories of this paper are: math
0
The categories of this paper are: hep-ph
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The categories of this paper are: alg-geom
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The categories of this paper are: ao-sci