CHEMIN, L.; SOUBIRAN, C.; CRIFO, Françoise; JASNIEWICZ, Gérard; KATZ, David; HESTROFFER, Daniel; UDRY, Stéphane

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CHEMIN, L.
sSE 2011

SOUBIRAN, C.
M2A 2011

CRIFO, Françoise
Galaxies, Etoiles, Physique, Instrumentation [GEPI]
Observatoire de Paris - Site de Paris [OP]

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Communication dans un congrès

Ce document a été publié dans

SF2A-2011: Proceedings of the Annual meeting of the French Society of Astronomy and Astrophysics, SF2A-2011: Proceedings of the Annual meeting of the French Society of Astronomy and Astrophysics, SF2A 2011: Annual meeting of the French Society of Astronomy and Astrophysics, 2011-06-20, Paris. 2011-12p. 271-274

Résumé en anglais

The Radial Velocity Spectrometer (RVS) on board of Gaia will perform a large spectroscopic survey to determine the radial velocities of some 1.5 × 10^8 stars. We present the status of ground-based observations of a sample of 1420 candidate standard stars designed to calibrate the RVS. Each candidate star has to be observed several times before Gaia launch (and at least once during the mission) to ensure that its radial velocity remains stable during the whole mission. Observations are performed with the high-resolution spectrographs SOPHIE, NARVAL and CORALIE, completed with archival data of the ELODIE and HARPS instruments. The analysis shows that about 7% of the current catalogue exhibits variations larger than the adopted threshold of 300 m s^{-1}. Consequently, those stars should be rejected as reference targets, due to the expected accuracy of the Gaia RVS. Emphasis is also put here on our observations of bright asteroids to calibrate the ground-based velocities by a direct comparison with celestial mechanics. It is shown that the radial velocity zero points of SOPHIE, NARVAL and CORALIE are consistent with each other, within the uncertainties. Despite some scatter, their temporal variations remain small with respect to our adopted stability criterion.< Réduire

Mots clés en anglais

Galaxy : kinematics and dynamics

Galaxy : structure

Stars: kinematics and dynamics

Minor planets

asteroids: general

Surveys

Techniques: radial velocities

Origine

Importé de hal

Unités de recherche

Laboratoire d'Astrophysique de Bordeaux (LAB) - UMR 5804