Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Galaxy Light Concentration. I. Index stability and the connection with
  galaxy structure, dynamics, and supermassive black holes   We explore the stability of different galaxy light concentration indices as a
function of the outermost observed galaxy radius. With a series of analytical
light-profile models, we show mathematically how varying the radial extent to
which one measures a galaxy's light can strongly affect the derived galaxy
concentration. The "mean concentration index", often used for parameterizing
high-redshift galaxies, is shown to be horribly unstable, even when modeling
one-component systems such as elliptical, dwarf elliptical and pure exponential
disk galaxies. The C_31 concentration index performs considerably better but is
also heavily dependent on the radial extent, and hence exposure depth, of any
given galaxy. We show that the recently defined central concentration index is
remarkably stable against changes to the outer radius, providing a meaningful
and reliable estimate of galaxy concentration. The index n from the r^(1/n)
models is shown to be monotonically related with the central concentration of
light, giving the index n a second and perhaps more tangible meaning. With a
sample of elliptical and dwarf elliptical galaxies, we present correlations
between the central light concentration and the global parameters: luminosity
(Pearson's r = -0.82), effective radius (r = 0.67), central surface brightness
(r = -0.88), and velocity dispersion (r = 0.80). The more massive elliptical
galaxies are shown to be more centrally concentrated. We speculate that the
physical mechanism behind the recently observed correlation between the central
velocity dispersion (mass) of a galaxy and the mass of its central supermassive
black hole may be connected with the central galaxy concentration. That is, we
hypothesize that it may not simply be the amount of mass in a galaxy but rather
how that mass is distributed that controls the mass of the central black hole.

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The categories of this paper are: econ
25
The categories of this paper are: patt-sol
31
The categories of this paper are: ao-sci
8
The categories of this paper are: hep-ex
13
The categories of this paper are: quant-ph
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The categories of this paper are: dg-ga
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The categories of this paper are: nucl-ex
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The categories of this paper are: funct-an
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The categories of this paper are: alg-geom
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The categories of this paper are: nlin
12
The categories of this paper are: nucl-th
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The categories of this paper are: eess
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The categories of this paper are: solv-int
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The categories of this paper are: hep-ph
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The categories of this paper are: atom-ph
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The categories of this paper are: q-fin