  The Radial Velocity Spectrograph (RVS) on board of Gaia needs to be
calibrated using stable reference stars known in advance. The catalogue
presented here has being built for that purpose. It includes 1420 radial
velocity standard star candidates selected on strict criteria in order to
fulfill the Gaia-RVS requirements. A large programme of ground based
observations is underway since 2006 to monitor these stars and verify their
stability which has to be better than 300 m/s over several years. The
observations have been made on the echelle spectrographs ELODIE and SOPHIE on
the 1.93-m telescope at Observatoire de Haute-Provence (OHP), NARVAL on the
Telescope Bernard Lyot at Observatoire du Pic du Midi and CORALIE on the
Euler-Swiss Telescope at La Silla. Data from the OHP and Geneva Observatory
archives have also been retrieved as well as HARPS spectra from the ESO
archive. We provide for each star a mean radial velocity in the SOPHIE scale,
derived from the combination of velocities measured with those instruments,
after having carefully estimated their differences of zero-points. In total
10214 radial velocity measurements have been obtained for the 1420 stars. With
a mean time baseline of 6.35 years, 92.9% of the candidates fulfill a target
stability criterion of 300 m/s. 343 stars are found to be constant at the level
of 100 m/s over 10 years. Comparisons with the catalogues of Nidever et
al.(2002) and Chubak et al.(2012) show an excellent agreement for FGK stars,
with zero-point differences lower than 100 m/s and a remarkably low RMS scatter
of 33 m/s in the case of Nidever et al.(2002), suggesting that the precision of
the catalogue presented here is better than this value. This catalog will
likely be useful for other large-scale spectroscopic surveys such as APOGEE,
Gaia-ESO, HERMES and LAMOST.
