Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: The First Generation of Virgo Cluster Dwarf Elliptical Galaxies?   In the light of the question whether most early-type dwarf (dE) galaxies in
clusters formed through infall and transformation of late-type progenitors, we
search for an imprint of such an infall history in the oldest, most centrally
concentrated dE subclass of the Virgo cluster: the nucleated dEs that show no
signatures of disks or central residual star formation. We select dEs in a
(projected) region around the central elliptical galaxies, and subdivide them
by their line-of-sight velocity into fast-moving and slow-moving ones. These
subsamples turn out to have significantly different shapes: while the fast dEs
are relatively flat objects, the slow dEs are nearly round. Likewise, when
subdividing the central dEs by their projected axial ratio into flat and round
ones, their distributions of line-of-sight velocities differ significantly: the
flat dEs have a broad, possibly two-peaked distribution, whereas the round dEs
show a narrow single peak. We conclude that the round dEs probably are on
circularized orbits, while the flat dEs are still on more eccentric or radial
orbits typical for an infalling population. In this picture, the round dEs
would have resided in the cluster already for a long time, or would even be a
cluster-born species, explaining their nearly circular orbits. They would thus
be the first generation of Virgo cluster dEs. Their shape could be caused by
dynamical heating through repeated tidal interactions. Further investigations
through stellar population measurements and studies of simulated galaxy
clusters would be desirable to obtain definite conclusions on their origin.

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The categories of this paper are: atom-ph
1
The categories of this paper are: cs
20
The categories of this paper are: acc-phys
2
The categories of this paper are: math
11
The categories of this paper are: hep-lat
7
The categories of this paper are: hep-th
9
The categories of this paper are: nlin
10
The categories of this paper are: q-bio
26
The categories of this paper are: bayes-an
4
The categories of this paper are: cond-mat
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The categories of this paper are: plasm-ph
15
The categories of this paper are: nucl-ex
30
The categories of this paper are: q-alg
8
The categories of this paper are: hep-ex
37
The categories of this paper are: supr-con
27
The categories of this paper are: comp-gas