J/A+A/580/A75 Velocity precision in the Gaia-ESO Survey (Jackson+, 2015)
The Gaia-ESO Survey: Empirical determination of the precision of stellar
radial velocities and projected rotation velocities.
Jackson R.J., Jeffries R.D., Lewis J., Koposov S.E., Sacco G.G.,
Randich S., Gilmore G., Asplund M., Binney J., Bonifacio P., Drew J.E.,
Feltzing S., Ferguson A.M.N., Micela G., Neguerela I., Prusti T., Rix H-W.,
Vallenari A., Alfaro E.J., Allende Prieto C., Babusiaux C., Bensby T.,
Blomme R., Bragaglia A., Flaccomio E., Francois P., Hambly N., Irwin M.,
Korn A.J., Lanzafame A.C., Pancino E., Recio-Blanco A., Smiljanic R.,
Van Eck S., Walton N., Bayo A., Bergemann M., Carraro G., Costado M.T.,
Damiani F., Edvardsson B., Franciosini E., Frasca A., Heiter U., Hill V.,
Hourihane A., Jof P., Lardo C., de Laverny P., Lind K., Magrini L.,
Marconi G., Martayan C., Masseron T., Monaco L., Morbidelli L.,
Prisinzano L., Sbordone L., Sousa S.G., Worley C.C., Zaggia S.
<Astron. Astrophys. 580, A75 (2015)>
=2015A&A...580A..75J 2015A&A...580A..75J
ADC_Keywords: Clusters, open
Keywords: stars: kinematics and dynamics -
open clusters and associations: general
Abstract:
Description:
The Gaia-ESO Survey (GES) is a large public spectroscopic survey at
the European Southern Observatory Very LargeTelescope. A key aim is to
provide precise radial velocities (RVs) and projected equatorial
velocities (vsini) for representative samples of Galactic stars, which
will complement information obtained by the Gaia astrometry satellite.
We present an analysis to empirically quantify the size and
distribution of uncertainties in RV and vsini using spectra from
repeated exposures of the same stars. We show that the uncertainties
vary as simple scaling functions of signal-to-noise ratio (S/N) and
vsini, that the uncertainties become larger with increasing
photospheric temperature, but that the dependence on stellar gravity,
metallicity and age is weak. The underlying uncertainty distributions
have extended tails that are better represented by Students
t-distributions than by normal distributions. Parametrised results are
provided, which enable estimates of the RV precision for almost all
GES measurements, and estimates of the vsini precision for stars in
young clusters, as a function of S/N, vsini and stellar temperature.
The precision of individual high S/N GES RV measurements is
0.22-0.26km/s, dependent on instrumental configuration.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table2.dat 71 439 Log of VLT/Flames observations used in the
analysis of RV and vsini measurement precision
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See also:
J/A+A/561/A94 : Velocities and photometry in Trumpler 20 (Donati+, 2014)
J/A+A/563/A94 : Kinematics of the Gamma Vel cluster (Jeffries+, 2014)
J/A+A/566/A50 : Classification of stellar spectra 644-681nm (Damiani+, 2014)
J/A+A/567/A55 : Metallicity of the gamma Vel cluster (Spina+, 2014)
J/A+A/569/A17 : Gaia-ESO Survey: NGC6705 (Cantat-Gaudin+, 2014)
J/A+A/572/A33 : Abundances from Gaia-ESO Survey (Mikolaitis+, 2014)
J/MNRAS/441/3127 : FeI oscillator strengths for Gaia-ESO (Ruffoni+, 2014)
J/A+A/573/A115 : Radial velocities in seven globular clusters (Lardo+, 2015)
J/A+A/574/L7 : Gaia-ESO Survey: Li-rich stars in NGC2547 (Sacco+, 2015)
J/A+A/575/A4 : Activity and accretion in gamma Vel and ChaI (Frasca+, 2015)
Byte-by-byte Description of file: table2.dat
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Bytes Format Units Label Explanations
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1- 5 A5 --- Filter Name of order sorting filter of spectrograph
("HR10", "HR15N" or "HR21")
7- 17 A11 "D/M/Y" Obs.date Date of observation (UTC)
19- 26 A8 "h:m:s" Obs.time Universal standard time of observation
27- 29 A3 --- --- [.0]
31- 32 I2 h RAh Right ascension field centre (J2000)
34- 35 I2 min RAm Right ascension field centre (J2000)
37- 40 F4.1 s RAs Right ascension field centre (J2000)
42 A1 --- DE- Declination sign of field centre (J2000)
43- 44 I2 deg DEd Declination field centre (J2000)
46- 47 I2 arcmin DEm Declination field centre (J2000)
49- 52 F4.1 arcsec DEs Declination field centre (J2000)
54- 57 I4 s Texp [600/2700] Exposure time of individual exposures
59 I1 --- Nexp [2/3] Number of exposures per observation block
61- 63 I3 --- Ntar [15/119] Number of stellar targets
with allocated fibres
65- 71 A7 --- Cluster Short name for cluster for targets in cluster
("Cha_I", "gam2vel", "rho_oph", "ic4665",
"ngc2264", "ngc2516", "ngc2547" or "ngc6633")
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Acknowledgements:
Richard Jackson, r.j.jackson(at)keele.ac.uk
(End) Richard Jackson [Keele University], Patricia Vannier [CDS] 20-Jul-2015