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The Gaia-ESO Survey: Empirical determination of the precision of stellar radial velocities and projected rotation velocities

Jackson, RJ, Jeffries, RD, Lewis, J, Koposov, SE, Sacco, GG, Randich, S, Gilmore, G, Asplund, M, Binney, J, Bonifacio, P, Drew, JE, Feltzing, S, Ferguson, AMN, Micela, G, Neguerela, I, Prusti, T, Rix, H-W, Vallenari, A, Alfaro, EJ, Prieto, CA , Babusiaux, C, Bensby, T, Blomme, R, Bragaglia, A, Flaccomio, E, Francois, P, Hambly, N, Irwin, M, Korn, AJ, Lanzafame, AC, Pancino, E, Recio-Blanco, A, Smiljanic, R, Van Eck, S, Walton, N, Bayo, A, Bergemann, M, Carraro, G, Costado, MT, Damiani, F, Edvardsson, B, Franciosini, E, Frasca, A, Heiter, U, Hill, V, Hourihane, A, Jofre, 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, SG, Worley, CC and Zaggia, S (2015) The Gaia-ESO Survey: Empirical determination of the precision of stellar radial velocities and projected rotation velocities. Astronomy & Astrophysics, 580. ISSN 1432-0746

1505.07019v1.pdf - Accepted Version

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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, that 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, that 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, dependent on instrumental configuration.

Item Type: Article
Uncontrolled Keywords: 0201 Astronomical And Space Sciences
Subjects: Q Science > QB Astronomy
Q Science > QC Physics
Divisions: Astrophysics Research Institute
Publisher: EDP Sciences
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Date Deposited: 23 Nov 2016 09:34
Last Modified: 04 Sep 2021 12:15
DOI or ID number: 10.1051/0004-6361/201526248
URI: https://researchonline.ljmu.ac.uk/id/eprint/4845
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