Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: The ATLAS3D Project - XXI. Correlations between gradients of local
  escape velocity and stellar populations in early-type galaxies   We explore the connection between the local escape velocity, V_esc, and the
stellar population properties in the ATLAS3D survey, a complete, volume-limited
sample of nearby early-type galaxies. We make use of ugriz photometry to
construct Multi-Gaussian Expansion models of the surface brightnesses of our
galaxies. We are able to fit the full range of surface brightness profiles
found in our sample, and in addition we reproduce the results of
state-of-the-art photometry in the literature with residuals of 0.04 mags. We
utilise these photometric models and SAURON integral-field spectroscopy,
combined with Jeans dynamical modelling, to determine the local V_esc derived
from the surface brightness. We find that the local V_esc is tightly correlated
with the Mgb and Fe5015 linestrengths and optical colours, and anti-correlated
with the Hbeta linestrength. In the case of the Mgb and Colour - V_esc
relations we find that the relation within individual galaxies follows the
global relation between different galaxies. We intentionally ignored any
uncertain contribution due to dark matter since we are seeking an empirical
description of stellar population gradients in early-type galaxies that is
ideal for quantitative comparison with model predictions. We identify a
population of galaxies that occur only at low V_esc that exhibit negative
gradients in the Mgb - and Colour -V_esc relations. These galaxies typically
have young central stellar populations and contain significant amounts of
molecular gas and dust. Combining these results with N-body simulations of
binary mergers we use the Mgb-V_esc relation to constrain the possible number
of dry mergers experienced by the local early-type galaxy population - a
typical massive ETG can have experienced only ~1.5 major mergers before
becoming a significant outlier in the Mgb-V_esc relation. [Abridged]

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The categories of this paper are: hep-lat
29
The categories of this paper are: funct-an
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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: q-bio
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The categories of this paper are: acc-phys
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The categories of this paper are: dg-ga
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The categories of this paper are: gr-qc
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The categories of this paper are: cmp-lg
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The categories of this paper are: q-alg
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The categories of this paper are: chao-dyn
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The categories of this paper are: solv-int
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The categories of this paper are: nlin
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The categories of this paper are: ao-sci
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The categories of this paper are: physics
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The categories of this paper are: nucl-ex