Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Wide Field CCD Surface Photometry of the Giant Elliptical Galaxy NGC
  4472 in the Virgo Cluster   We present deep wide field (16'.4 x 16'.4) Washington CT1 CCD surface
photometry of the giant elliptical galaxy NGC 4472, the brightest member in the
Virgo cluster. Our data cover a wider field than any previous CCD photometry as
well as going deeper. Surface brightness profiles of NGC 4472 are not well fit
by a single King model, but they can be fit approximately by two King models:
with separate models for the inner and outer regions. Surface brightness
profiles for the outer region can also be fit approximately by a deVaucouleurs
law. There is clearly a negative color gradient within 3' of NGC 4472, in the
sense that the color gets bluer with increasing radius. The slope of the color
gradient for this region is derived to be $\Delta \mu (C-T_1)$ = -0.08 mag
arcsec$^{-2}$ for $\Delta \log r =1$, which corresponds to a metallicity
gradient of $\Delta$ [Fe/H] $= -0.2$ dex. However, the surface color gets
redder slowly with increasing radius beyond 3'. A comparison of the structural
parameters of NGC 4472 in C and T1 images has shown that there is little
difference in the ellipse shapes between isochromes and isophotes. In addition,
photometric and structural parameters of NGC 4472 have been determined.

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The categories of this paper are: cmp-lg
15
The categories of this paper are: nucl-ex
19
The categories of this paper are: eess
11
The categories of this paper are: hep-lat
9
The categories of this paper are: nlin
8
The categories of this paper are: hep-ex
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The categories of this paper are: chem-ph
31
The categories of this paper are: ao-sci
16
The categories of this paper are: stat
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The categories of this paper are: dg-ga
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The categories of this paper are: acc-phys
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The categories of this paper are: mtrl-th
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The categories of this paper are: gr-qc
18
The categories of this paper are: econ
7
The categories of this paper are: hep-th
33
The categories of this paper are: plasm-ph