Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: A first study of the galaxy HRG 2304 and its companion AM 1646-795
  (NED01)   Aims. We report the first study of the peculiar ring-like galaxy HRG 2304
(NED02),which was previously classified as a ring galaxy with an elliptical
smooth ring. This object was selected to prove that it is a candidate for the
Solitaire-type ring galaxies in an early stage of ring formation. The main goal
of this work is to provide the spectral characteristics of the current object
and its companion AM 1646-795 (NED01). Methods. The study is based on
spectroscopic observations in the optical band to highlight the characteristics
of this interacting galaxy. To investigate the star formation history of HRG
2304 we used the stellar population synthesis code STARLIGHT. The direct V and
B broad band images were used to enhance some fine structures. Results. Along
the entire long-slit signal, the spectra of HRG 2304 and its companion resemble
that of an early-type galaxy. We estimated a heliocentric systemic redshift of
z = 0.0415, corresponding to heliocentric velocities of 12449 km s-1 for HRG
2304 (NED02) and 12430 km s-1 for AM1646-795 (NED01). The spatial variation in
the contribution of the stellar population components for both objects are
dominated by an old stellar population 2x10^9 < t < 13x10^9 yr. The observed
radial-velocity distribution and the fine structures around HRG 2304 suggest an
ongoing tidal interaction of both galaxies. Conclusions.The spectroscopic
results and the morphological peculiarities of HRG 2304 can be adequately
interpreted as an ongoing interaction with the companion galaxy. Both galaxies
are early-type, the companion is elliptical, and the smooth distribution of the
material around HRG 2304 and its off-center nucleus in the direction of
AM1646-795 (NED01) characterize HRG 2304 as a Solitaire-type galaxy candidate
in an early stage of ring formation.

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The categories of this paper are: hep-th
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The categories of this paper are: hep-ex
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The categories of this paper are: alg-geom
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The categories of this paper are: math-ph
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The categories of this paper are: physics
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The categories of this paper are: q-alg
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The categories of this paper are: chem-ph
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The categories of this paper are: cond-mat
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The categories of this paper are: funct-an
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The categories of this paper are: patt-sol
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The categories of this paper are: solv-int
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The categories of this paper are: cs
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The categories of this paper are: stat
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The categories of this paper are: atom-ph
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The categories of this paper are: plasm-ph
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The categories of this paper are: mtrl-th