Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Red Clump Stars in the Sagittarius Tidal Streams   We have probed a section (l ~ 150, b ~ -60) of the trailing tidal arm of the
Sagittarius dwarf spheroidal galaxy by identifying a sample of Red Clump stream
stars. Red Clump stars are not generally found in the halo field, but are found
in significant numbers in both the Sagittarius galaxy and its tidal streams,
making them excellent probes of stream characteristics. Our target sample was
selected using photometric data from the Sloan Digital Sky Survey, Data Release
6, which was constrained in color to match the Sagittarius Red Clump stars.
Spectroscopic observations of the target stars were conducted at Kitt Peak
National Observatory using the WIYN telescope. The resulting spectroscopic
sample is magnitude limited and contains both main sequence disk stars and
evolved Red Clump stars. We have developed a method to systematically separate
these two stellar classes using kinematic information and a Bayesian approach
for surface gravity determination. The resulting Red Clump sample allows us to
determine an absolute stellar density of {\rho} = 2.7 +/- 0.5 RC stars kpc-3 at
this location in the stream. Future measurements of stellar densities for a
variety of populations and at various locations along the streams will lead to
a much improved understanding of the original nature of the Sagittarius galaxy
and the physical processes controlling its disruption and subsequent stream
generation.

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The categories of this paper are: hep-ex
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The categories of this paper are: hep-lat
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The categories of this paper are: alg-geom
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The categories of this paper are: quant-ph
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The categories of this paper are: acc-phys
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The categories of this paper are: ao-sci
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The categories of this paper are: patt-sol
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The categories of this paper are: gr-qc
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The categories of this paper are: funct-an
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The categories of this paper are: comp-gas
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The categories of this paper are: physics
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The categories of this paper are: cmp-lg
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The categories of this paper are: q-fin
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The categories of this paper are: hep-th
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The categories of this paper are: econ
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The categories of this paper are: cond-mat