Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: The lenticular galaxy NGC3607: stellar population, metallicity and
  ionised gas   In this work we derive clues to the formation scenario and ionisation source
of the lenticular galaxy NGC 3607 by means of metallicity gradients, stellar
population and emission lines properties. We work with long-slit spectroscopy
from which we (i) study the radial distribution of the equivalent widths of
conspicuous metallic absorption features, (ii) infer on the star-formation
history (with a stellar population synthesis algorithm), and (iii) investigate
the ionisation source responsible for a few strong emission lines. Negative
radial gradients are observed for most of the absorption features of NGC 3607.
Compared to the external parts, the central region has a deficiency of alpha
elements and higher metallicity, which implies different star-formation
histories in both regions. At least three star formation episodes are detected,
with ages within 1-13 Gyr. The dynamical mass and the $Mg_2$ gradient slope are
consistent with mergers being important contributors to the formation mechanism
of NGC 3607. Emission-line ratios indicate the presence of a LINER at the
centre of NGC 3607. Contribution of hot, old stars to the gas ionisation
outside the central region is detected. Evidence drawn from this work suggest
small mergers as important contributors to the formation of NGC 3607, a
scenario consistent with the star-formation episodes.

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The categories of this paper are: hep-lat
17
The categories of this paper are: q-fin
18
The categories of this paper are: econ
27
The categories of this paper are: comp-gas
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The categories of this paper are: nucl-th
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The categories of this paper are: stat
1
The categories of this paper are: cs
7
The categories of this paper are: hep-th
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The categories of this paper are: eess
34
The categories of this paper are: chem-ph
4
The categories of this paper are: cond-mat
20
The categories of this paper are: acc-phys
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The categories of this paper are: mtrl-th
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The categories of this paper are: dg-ga
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The categories of this paper are: funct-an
10
The categories of this paper are: q-bio