The Sixth Data Release of the Radial Velocity Experiment (RAVE). I. Survey Description, Spectra, and Radial Velocities

The Radial Velocity Experiment (Rave) is a magnitude-limited (9 I <12) spectroscopic survey of Galactic stars randomly selected in Earth's southern hemisphere. The Ravemedium-resolution spectra (R similar to 7500) cover the Ca-triplet region (8410-8795 angstrom). The sixth and final data release (DR6) is based on 518,387 observations of 451,783 unique stars. Raveobservations were taken between 2003 April 12 and 2013 April 4. Here we present the genesis, setup, and data reduction of Raveas well as wavelength-calibrated and flux-normalized spectra and error spectra for all observations in RaveDR6. Furthermore, we present derived spectral classification and radial velocities for the Ravetargets, complemented by cross-matches with Gaia DR2 and other relevant catalogs. A comparison between internal error estimates, variances derived from stars with more than one observing epoch, and a comparison with radial velocities of Gaia DR2 reveals consistently that 68% of the objects have a velocity accuracy better than 1.4 km s(-1), while 95% of the objects have radial velocities better than 4.0 km s(-1). Stellar atmospheric parameters, abundances and distances are presented in a subsequent publication. The data can be accessed via the Ravewebsite (http://rave-survey.org) or the Vizier database.