Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: The Photometric Plane of Elliptical Galaxies   The Sersic r^(1/n) index n of an elliptical galaxy (or bulge) has recently
been shown to correlate strongly (r=0.8) with a galaxy's central velocity
dispersion. This index could therefore prove extremely useful and
cost-effective (in terms of both telescope time and data reduction) for many
fields of extragalactic research. It is a purely photometric quantity which
apparently not only traces the mass of a bulge but has additionally been shown
to reflect the degree of bulge concentration. This paper explores the affect of
replacing the central velocity dispersion term in the Fundamental Plane with
the Sersic index n. Using a sample of early-type galaxies from the Virgo and
Fornax clusters, various (B-band) `Photometric Planes' were constructed and
found to have a scatter of 0.14-0.17 dex in log(r_e), or a distance error of
38-48% per galaxy (the higher values arising from the inclusion of the S0
galaxies). The corresponding Fundamental Plane yielded a 33-37% error in
distance for the same galaxy (sub-)samples (i.e. ~15-30% less scatter). The
gains in using a hyperplane (i.e. adding the Sersic index to the Fundamental
Plane as a fourth parameter) were small, giving a 27-33% error in distance,
depending on the galaxy sample used. The Photometric Plane has been used here
to estimate the Virgo-Fornax distance modulus; giving a value of
\Delta\mu=0.62(+/-0.30) mag (cf. 0.51(+/-0.21), HST Key Project on the
Extragalactic distance Scale). The prospects for using the Photometric Plane at
higher redshift appears promising. Using published data on the intermediate
redshift cluster Cl 1358+62 (z=0.33) gave a Photometric Plane distance error of
35-41% per galaxy.

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The categories of this paper are: plasm-ph
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The categories of this paper are: quant-ph
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The categories of this paper are: atom-ph
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The categories of this paper are: eess
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The categories of this paper are: cond-mat
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The categories of this paper are: patt-sol
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The categories of this paper are: alg-geom
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The categories of this paper are: q-fin
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The categories of this paper are: cmp-lg
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The categories of this paper are: cs
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The categories of this paper are: math-ph
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The categories of this paper are: chao-dyn
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The categories of this paper are: hep-ph
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The categories of this paper are: hep-th
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The categories of this paper are: funct-an
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The categories of this paper are: adap-org