Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: The SAURON Project - XIV. No escape from V$_{\mathrm{esc}}$: a global
  and local parameter in early-type galaxy evolution   We present the results of an investigation of the local escape velocity
(Vesc) - line strength index relationship for 48 early type galaxies from the
SAURON sample, the first such study based on a large sample of galaxies with
both detailed integral field observations and extensive dynamical modelling.
Values of Vesc are computed using Multi Gaussian Expansion (MGE) photometric
fitting and axisymmetric, anisotropic Jeans' dynamical modelling simultaneously
on HST and ground-based images. We determine line strengths and escape
velocities at multiple radii within each galaxy, allowing an investigation of
the correlation within individual galaxies as well as amongst galaxies. We find
a tight correlation between Vesc and the line-strength indices. For Mgb we find
that this correlation exists not only between different galaxies but also
inside individual galaxies - it is both a local and global correlation. The
relation within individual galaxies has the same slope and offset as the global
relation to a good level of agreement, though there is significant intrinsic
scatter in the local gradients. We transform our line strength index
measurements to the single stellar population (SSP) equivalent age (t),
metallicity ([Z/H]) and enhancement ([$\alpha$/Fe]) and carry out a principal
component analysis of our SSP and Vesc data. We find that in this
four-dimensional parameter space the galaxies in our sample are to a good
approximation confined to a plane, given by $\log
\mathrm({V}_{\mathrm{esc}}/500\mathrm{km/s}) = 0.85 \mathrm{[Z/H]} + 0.43 \log
(\mathrm{t}/\mathrm{Gyrs})$ - 0.20. It is surprising that it is a combination
of age and metallicity that is conserved; this may indicate a 'conspiracy'
between age and metallicity or a weakness in the SSP models.

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The categories of this paper are: dg-ga
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The categories of this paper are: math-ph
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The categories of this paper are: hep-th
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The categories of this paper are: gr-qc
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The categories of this paper are: q-fin
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The categories of this paper are: acc-phys
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The categories of this paper are: atom-ph
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The categories of this paper are: stat
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The categories of this paper are: hep-ph
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The categories of this paper are: eess
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The categories of this paper are: mtrl-th
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The categories of this paper are: chem-ph
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The categories of this paper are: solv-int
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The categories of this paper are: hep-ex
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The categories of this paper are: plasm-ph
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The categories of this paper are: supr-con