Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: The Detailed Evolution of E+A Galaxies into Early Types   Post-starburst, or E+A galaxies, are the best candidates for galaxies in
transition from being gas-rich and star-forming to gas-poor and
passively-evolving via galaxy-galaxy mergers. To determine what E+A galaxies
become after their young stellar populations fade away, we present the detailed
morphologies of 21 E+As using HST images. We find that E+As are similar to
early types in that they have large bulge fractions (median B/T = 0.59), high
Sersic index (n > 4), and high concentration indices (C > 4.3). The large
fraction (70%) of E+As with positive color gradients (i.e., bluer nuclei)
indicates that the young stellar populations are more concentrated than the old
populations. We show that these positive color gradients can evolve into the
negative gradients typical in E/S0s if the central parts of these galaxies are
metal enhanced. E+A galaxies stand apart from the E/S0s in the edge-on
projection of the Fundamental Plane, implying that E+As have, on average, a M/L
that is ~3.8 times smaller than that of E/S0s. The tilt of the E+A FP indicates
that the variation among stellar populations in these galaxies is closely tied
to their structural parameters such that smaller or less massive galaxies have
smaller M/L. We find a population of unresolved compact sources in nine E+As
(45%). Their colors and luminosities are consistent with the hypothesis that
these are newly formed star clusters. The bright end of the cluster LF is
fainter in redder E+A's, suggesting that the young star cluster systems have
faded or been disrupted as the merger remnant aged. In summary, the
morphologies, color profiles, scaling relations, and cluster populations are
all consistent with the hypothesis that E+As galaxies are the results of
mergers that evolve into early-type galaxies.

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The categories of this paper are: mtrl-th
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The categories of this paper are: hep-ph
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The categories of this paper are: q-alg
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The categories of this paper are: dg-ga
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The categories of this paper are: hep-lat
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The categories of this paper are: acc-phys
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The categories of this paper are: nlin
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The categories of this paper are: math
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The categories of this paper are: plasm-ph
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The categories of this paper are: cmp-lg
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The categories of this paper are: hep-ex
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The categories of this paper are: gr-qc
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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: hep-th
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The categories of this paper are: adap-org