Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Blue horizontal branch stars in the Sloan Digital Sky Survey: I. Sample
  selection and structure in the Galactic halo   We isolate samples of 733 bright (g < 18) and 437 faint (g > 18)
high-Galactic latitude blue horizontal branch stars with photometry and
spectroscopy in the Sloan Digital Sky Survey (SDSS). Comparison of independent
photometric and spectroscopic selection criteria indicates that contamination
from F and blue-straggler stars is less than 10% for bright stars (g<18) and
about 25% for faint stars (g>18), and this is qualitatively confirmed by proper
motions based on the USNO-A catalog as first epoch. Analysis of repeated
observations shows that the errors in radial velocity are approximately 26
km/s.
  A relation between absolute magnitude and color is established using the
horizontal branches of halo globular clusters observed by SDSS. Bolometric
corrections and colors are synthesized in the SDSS filters from model spectra.
The redder stars agree well in absolute magitude with accepted values for RR
Lyrae stars. The resulting photometric distances are accurate to about 0.2
magnitudes, with a median of about 25 kpc. Modest clumps in phase space exist
and are consistent with the previously reported tidal stream of the Sagittarius
dwarf galaxy.
  The sample is tabulated in electronic form in the online version of this
article, or by request to the authors.

24
The categories of this paper are: dg-ga
26
The categories of this paper are: bayes-an
25
The categories of this paper are: patt-sol
35
The categories of this paper are: mtrl-th
3
The categories of this paper are: physics
5
The categories of this paper are: gr-qc
34
The categories of this paper are: chem-ph
27
The categories of this paper are: comp-gas
12
The categories of this paper are: nucl-th
1
The categories of this paper are: cs
20
The categories of this paper are: acc-phys
13
The categories of this paper are: quant-ph
31
The categories of this paper are: ao-sci
33
The categories of this paper are: plasm-ph
17
The categories of this paper are: q-fin
8
The categories of this paper are: hep-ex