Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Spectrophotometric Investigation of a Sample of Tidal Dwarf Galaxies   We define a Tidal Dwarf Galaxy (TDG) as a self-gravitating entity of
dwarf-galaxy mass built from tidal material expelled during interactions. We
then summarize our findings on broad-band imaging and spectroscopy of a sample
of TDG candidates in a sequence of interacting systems. Evidence for decoupled
kinematics in the ionized gas have been found in several objects. This could
indicate that they are bound galaxies and therefore genuine TDGs. As a detailed
example we analyze the system AM 1159-530, where surprisingly high velocity
gradients have been measured.

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The categories of this paper are: gr-qc
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The categories of this paper are: physics
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The categories of this paper are: mtrl-th
31
The categories of this paper are: ao-sci
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The categories of this paper are: eess
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The categories of this paper are: stat
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The categories of this paper are: chem-ph
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The categories of this paper are: q-alg
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The categories of this paper are: nucl-th
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The categories of this paper are: solv-int
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The categories of this paper are: q-bio
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The categories of this paper are: plasm-ph
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The categories of this paper are: hep-th
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The categories of this paper are: adap-org
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The categories of this paper are: atom-ph
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The categories of this paper are: nucl-ex