J/AJ/132/714 QUEST RR Lyrae survey. II. Halo overdensities (Vivas+, 2006)
The QUEST RR Lyrae survey. II. The halo overdensities in the first catalog.
Vivas A.K., Zinn R.
<Astron. J., 132, 714-728 (2006)>
=2006AJ....132..714V 2006AJ....132..714V
ADC_Keywords: Stars, variable ; Positional data ; Stars, distances
Keywords: Galaxy: halo - Galaxy: structure - stars: variables: other
Abstract:
The first catalog of the RR Lyrae stars (RRLSs) in the Galactic halo
by the Quasar Equatorial Survey Team (QUEST) has been searched for
significant overdensities that may be debris from disrupted dwarf
galaxies or globular clusters. These RRLSs are contained in a band 23
wide in declination that spans 165° in right ascension and lie 4
to 60kpc from the Sun. Away from the major overdensities, the
distribution of these stars is adequately fitted by a smooth halo
model, in which the flattening of the halo decreases with increasing
galactocentric distance (as reported by Preston et al.,
1991ApJ...375..121P 1991ApJ...375..121P). This model was used to estimate the background
of RRLSs on which the halo overdensities are overlaid. A procedure was
developed for recognizing groups of stars that constitute significant
overdensities with respect to this background. To test this procedure,
a Monte Carlo routine was used to make artificial RRLS surveys that
follow the smooth halo model but with Poissondistributed noise in the
numbers of RRLSs and, within limits, random variations in the
positions and magnitudes of the artificial stars. The 104 artificial
surveys created by this routine were examined for significant groups
in exactly the same way as the QUEST survey.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table2.dat 51 457 Galactic coordinates and distances of the RRLS
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See also:
J/AJ/127/1158 : QUEST RR Lyrae Survey first catalog (Vivas+, 2004)
Byte-by-byte Description of file: table2.dat
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Bytes Format Units Label Explanations
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1- 3 I3 --- [VZA2004] Identification number (same as Paper I,
Vivas et al., Cat. J/AJ/127/1158)
5- 10 F6.2 deg GLON Galactic longitude
12- 17 F6.2 deg GLAT Galactic latitude
19- 23 F5.2 mag Vmag0 Extinction corrected V band magnitude
25- 29 F5.1 kpc x Galactocentric X coordinate
31- 35 F5.1 kpc y Galactocentric Y coordinate
37- 41 F5.1 kpc z Galactocentric Z coordinate
43- 46 F4.1 kpc RHel Heliocentric distance
48- 51 F4.1 kpc RGal Galactocentric distance
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History:
From electronic version of the journal
(End) Greg Schwarz [AAS], Patricia Vannier [CDS] 11-Jan-2008