Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: A Numerical Study of Boson Stars: Einstein Equations with a Matter
  Source   The study of the properties and dynamics of self-gravitating bosonic objects
in Einstein gravity was conducted. We studied self-coupled boson stars and
determined the quasinormal mode (QNM) frequencies of stable boson stars in
spherical symmetry. The study was carried out in the standard Einstein theory
of General Relativity and in Brans-Dicke theory. We also studied the formation
of these objects in Brans-Dicke theory showing that they can form from the
self-gravitation of bosonic matter. We also studied the studied the possibility
of a bosonic halo surrounding galaxies.
  After an extensive study in spherical symmetry we carried out numerical
studies of boson star dynamics in full 3+1 dimension. One focus of the 3D study
was on the validation of the numerical code constructed to solve Einstein
equations with matter sources. Boson Stars do not suffer from the surface
problems of neutron stars or the singularities of black holes. The code was
first tested with spherical perturbations and compared with the spherical
results. We determined the coordinate conditions needed to provide stable
evolutions. We then went on to study their behavior under non-spherical
perturbations. We reproduced the QNM frequencies of the stars, as determined by
perturbation studies carried out by other groups. The energy generated by the
perturbation was studied with different radiation indicators. We also observed
the collapse to black holes of unstable boson-star configurations. We simulated
the collision of two boson stars. This is of interest as the two body problem
is as yet unresolved in general relativity.

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The categories of this paper are: mtrl-th
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The categories of this paper are: bayes-an
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The categories of this paper are: comp-gas
6
The categories of this paper are: astro-ph
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The categories of this paper are: q-fin
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The categories of this paper are: ao-sci
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The categories of this paper are: nucl-th
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The categories of this paper are: eess
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The categories of this paper are: cmp-lg
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The categories of this paper are: q-bio
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The categories of this paper are: cond-mat
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The categories of this paper are: acc-phys
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The categories of this paper are: hep-lat
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The categories of this paper are: physics
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The categories of this paper are: nlin
1
The categories of this paper are: cs