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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. and Bonifacio, P., et al. (2015) In Astronomy & Astrophysics 580.
Abstract
Context. The Gaia-ESO Survey (GES) is a large public spectroscopic survey at the European Southern Observatory Very Large Telescope. Aims. A key aim is to provide precise radial velocities (RVs) and projected equatorial velocities (v sin i) for representative samples of Galactic stars, which will complement information obtained by the Gaia astrometry satellite. Methods. We present an analysis to empirically quantify the size and distribution of uncertainties in RV and v sin i using spectra from repeated exposures of the same stars. Results. We show that the uncertainties vary as simple scaling functions of signal-to-noise ratio (S/N) and v sin i, that the uncertainties become larger with increasing photospheric temperature, but that the... (More)
Context. The Gaia-ESO Survey (GES) is a large public spectroscopic survey at the European Southern Observatory Very Large Telescope. Aims. A key aim is to provide precise radial velocities (RVs) and projected equatorial velocities (v sin i) for representative samples of Galactic stars, which will complement information obtained by the Gaia astrometry satellite. Methods. We present an analysis to empirically quantify the size and distribution of uncertainties in RV and v sin i using spectra from repeated exposures of the same stars. Results. We show that the uncertainties vary as simple scaling functions of signal-to-noise ratio (S/N) and v sin i, 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 Student's t-distributions than by normal distributions. Conclusions. Parametrised results are provided, which enable estimates of the RV precision for almost all GES measurements, and estimates of the v sin i precision for stars in young clusters, as a function of S/N, v sin i and stellar temperature. The precision of individual high S/N GES RV measurements is 0.22-0.26 km s(-1), dependent on instrumental configuration. (Less)
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subject
keywords
stars: kinematics and dynamics, open clusters and associations: general
in
Astronomy & Astrophysics
volume
580
publisher
EDP Sciences
external identifiers
  • wos:000360020200075
  • scopus:84938867148
ISSN
0004-6361
DOI
10.1051/0004-6361/201526248
language
English
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yes
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83c70f3a-b90a-476b-958e-031793c28b22 (old id 8080425)
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2015-10-26 14:24:55
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2017-05-28 03:54:29
@article{83c70f3a-b90a-476b-958e-031793c28b22,
  abstract     = {Context. The Gaia-ESO Survey (GES) is a large public spectroscopic survey at the European Southern Observatory Very Large Telescope. Aims. A key aim is to provide precise radial velocities (RVs) and projected equatorial velocities (v sin i) for representative samples of Galactic stars, which will complement information obtained by the Gaia astrometry satellite. Methods. We present an analysis to empirically quantify the size and distribution of uncertainties in RV and v sin i using spectra from repeated exposures of the same stars. Results. We show that the uncertainties vary as simple scaling functions of signal-to-noise ratio (S/N) and v sin i, 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 Student's t-distributions than by normal distributions. Conclusions. Parametrised results are provided, which enable estimates of the RV precision for almost all GES measurements, and estimates of the v sin i precision for stars in young clusters, as a function of S/N, v sin i and stellar temperature. The precision of individual high S/N GES RV measurements is 0.22-0.26 km s(-1), dependent on instrumental configuration.},
  articleno    = {A75},
  author       = {Jackson, R. J. and Jeffries, R. D. and Lewis, J. and Koposov, S. E. and Sacco, G. G. and Randich, S. and Gilmore, G. and Asplund, M. and Binney, J. and Bonifacio, P. and Drew, J. E. and Feltzing, Sofia and Ferguson, A. M. N. and Micela, G. and Neguerela, I. and Prusti, T. and Rix, H. -W. and Vallenari, A. and Alfaro, E. J. and Prieto, C. Allende and Babusiaux, C. and Bensby, Thomas and Blomme, R. and Bragaglia, A. and Flaccomio, E. and Francois, P. and Hambly, N. and Irwin, M. and Korn, A. J. and Lanzafame, A. C. and Pancino, E. and Recio-Blanco, A. and Smiljanic, R. and Van Eck, S. and Walton, N. and Bayo, A. and Bergemann, M. and Carraro, G. and Costado, M. T. and Damiani, F. and Edvardsson, B. and Franciosini, E. and Frasca, A. and Heiter, U. and Hill, V. and Hourihane, A. and Jofre, P. and Lardo, C. and de Laverny, P. and Lind, K. and Magrini, L. and Marconi, G. and Martayan, C. and Masseron, T. and Monaco, L. and Morbidelli, L. and Prisinzano, L. and Sbordone, L. and Sousa, S. G. and Worley, C. C. and Zaggia, S.},
  issn         = {0004-6361},
  keyword      = {stars: kinematics and dynamics,open clusters and associations: general},
  language     = {eng},
  publisher    = {EDP Sciences},
  series       = {Astronomy & Astrophysics},
  title        = {The Gaia-ESO Survey: Empirical determination of the precision of stellar radial velocities and projected rotation velocities},
  url          = {http://dx.doi.org/10.1051/0004-6361/201526248},
  volume       = {580},
  year         = {2015},
}