Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: CCD Photometry of the Globular Cluster NGC 4833 and Extinction Near the
  Galactic Plane   We present CCD photometry for the Galactic globular cluster NGC 4833. Our BVI
color magnitude diagrams (CMD) extend from above the red giant branch (RGB) tip
to several magnitudes below the main sequence turnoff. The principal sequences
of the cluster show the effects of differential reddening. We have created a
local extinction map, consistent with IRAS and COBE/DIRBE dust maps of the
region. We use our map to correct the colors and magnitudes of each star to the
value at the cluster center. The cluster horizontal branch (HB) is
predominately blueward of the instability strip with 13 confirmed RR Lyrae
variables and 5 additional RR Lyrae candidates. Using the 11 confirmed RR
Lyraes measured on our images, and the differential reddening corrected
photometry we calculate V(HB) = 15.56 +/- 0.063. We have used the simultaneous
reddening and metallicity method of Sarajedini (1994) to find the mean
reddening of the cluster E(B-V) = 0.32 +/- 0.03, and the mean metallicity
[Fe/H] = -1.83 +/- 0.14. As for the age of NGC 4833, we find provisional
evidence that NGC 4833 is 2 +/- 1 Gyr older than the average of M92 and M5. A
more definitive conclusion must await higher resolution imaging of the cluster
core where the effects of differential reddening are minimized.

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The categories of this paper are: eess
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The categories of this paper are: hep-ex
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The categories of this paper are: atom-ph
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The categories of this paper are: mtrl-th
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The categories of this paper are: cmp-lg
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The categories of this paper are: solv-int
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The categories of this paper are: math-ph
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The categories of this paper are: cond-mat
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The categories of this paper are: physics
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The categories of this paper are: chao-dyn
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The categories of this paper are: stat
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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: nucl-th
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The categories of this paper are: acc-phys
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The categories of this paper are: hep-ph