J/AJ/136/1645 Spectroscopy of bright QUEST RR Lyrae stars (Vivas+, 2008)
Spectroscopy of bright QUEST RR Lyrae stars:
velocity substructures toward Virgo.
Vivas A.K., Jaffe Y.L., Zinn R., Winnick R., Duffau S., Mateu C.
<Astron. J., 136, 1645-1657 (2008)>
=2008AJ....136.1645V 2008AJ....136.1645V
ADC_Keywords: Stars, variable ; Radial velocities ; Abundances, [Fe/H]
Keywords: Galaxy: halo - Galaxy: kinematics and dynamics - Galaxy: structure -
stars: variables: other
Abstract:
Using a sample of 43 bright (V<16.1, distance <13kpc) RR Lyrae
stars (RRLs) from the QUasar Equatorial Survey with spectroscopic
radial velocities and metallicities, we find that several separate
halo substructures contribute to the Virgo overdensity (VOD). While
there is little evidence of a halo substructure in the spatial
distribution of these stars, their distribution in radial velocity
reveals two moving groups. These results are reinforced when the
sample is combined with a sample of blue horizontal branch stars that
were identified in the Sloan Digital Sky Survey, and the combined
sample provides evidence for one additional moving group.
Description:
We obtained a total of 88 spectra of the 44 RRLs with three different
telescopes between 2001 and 2007.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table3.dat 85 43 Position, distance, velocity and metallicity
of the 43 RRLs
table2.dat 48 86 Individual observations of the sample of 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: table3.dat
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Bytes Format Units Label Explanations
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1- 3 I3 --- [VZA2004] QUEST Identification number
5- 14 F10.6 deg RAdeg Right Ascension in decimal degrees (J2000)
16- 24 F9.6 deg DEdeg Declination in decimal degrees (J2000)
26- 30 F5.2 mag Vmag Extinction corrected mean V band magnitude
32- 33 A2 --- Type Type of RR Lyrae star
35- 41 F7.5 d Per Period
43- 54 F12.4 d HJD0 Heliocentric Julian Date at maximum light
56- 59 F4.1 kpc Dist Distance from the Sun
61 I1 --- Nsp Number of spectra available
63 I1 --- Nfit Number of spectra used to fit radial velocity
curve
65- 68 I4 km/s Vgamma Systemic velocity
70- 71 I2 km/s sigfit ? Error in fit of radial velocity curve
73- 74 I2 km/s e_Vgamma The 1σ error in Vgamma
76- 79 I4 km/s Vgsr Velocity in galactic rest frame
81- 85 F5.2 [Sun] [Fe/H] ? Metallicity
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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] QUEST Identification number
5- 16 F12.4 d JD Julian Date of observation
18- 21 I4 s Texp Exposure time
23- 28 A6 --- Tel Telescope used to make observation
30- 33 F4.2 --- Phase Pulsation phase of observation
35- 38 I4 km/s HRV Heliocentric radial velocity
40- 41 I2 km/s e_HRV The 1σ error in HRV
43- 47 F5.2 [Sun] [Fe/H] ? Metallicity
48 A1 --- u_[Fe/H] Uncertainty flag on [Fe/H] (1)
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Note (1): Uncertain measurements due to low SNR of the spectrogram. This
measurement was not taken into account for calculation of the mean
[Fe/H] unless it was the only available measurement for the star.
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History:
From electronic version of the journal
(End) Greg Schwarz [AAS], Patricia Vannier [CDS] 08-Apr-2011