GAIA SPECTROSCOPY: PROCESSING, PERFORMANCES AND SCIENTIFIC RETURNS

During the five years of the mission, the Gaia spectrograph, the Radial Velocity Spectrometer (RVS) will repeatedly survey the celestial sphere down to magnitude V similar to 47-18. This talk presents: (i) the system which is currently developed within the Gaia Data Processing and Analysis Consortium (DPAC) to reduce and calibrate the spectra and to derive the radial and rotational velocities, (ii) the RVS expected performances and (iii) scientific returns.