Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Substructure and Tidal Streams in the Andromeda Galaxy and its
  Satellites   Tidal streams from existing and destroyed satellite galaxies populate the
outer regions of the Andromeda galaxy (M31). This inhomogeneous debris can be
studied without many of the obstacles that plague Milky Way research. We review
the history of tidal stream research in M31, and in its main satellite
galaxies. We highlight the numerous tidal streams observed around M31, some of
which reside at projected distances of up to 120 kpc from the center of this
galaxy. Most notable is the Giant Stellar Stream, a signature of the most
recent significant accretion event in the M31 system. This event involved an
early-type progenitor of ~10^9 solar masses that came within a few kpc of M31's
center roughly a gigayear ago; almost all of the inner halo debris (within 50
kpc) in M31 can be tied either directly or indirectly to this event. We draw
attention to the fact that most of M31's outer halo globular clusters lie
preferentially on tidal streams and discuss the potential this offers to use
these systems as probes of the accretion history. Tidal features observed
around M33, M32, NGC 205 and NGC 147 are also reviewed. We conclude by
discussing future prospects for this field.

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The categories of this paper are: nucl-th
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The categories of this paper are: bayes-an
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The categories of this paper are: mtrl-th
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The categories of this paper are: adap-org
31
The categories of this paper are: ao-sci
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The categories of this paper are: stat
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The categories of this paper are: gr-qc
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The categories of this paper are: hep-ex
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The categories of this paper are: dg-ga
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The categories of this paper are: physics
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The categories of this paper are: chao-dyn
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The categories of this paper are: hep-th
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The categories of this paper are: comp-gas
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The categories of this paper are: cond-mat
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The categories of this paper are: atom-ph
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The categories of this paper are: funct-an