15.3.12 RAVE DR6
The Radial Velocity Experiment (RAVE) is a magnitude-limited () survey of Galactic stars randomly selected in the southern hemisphere. The Rave medium-resolution spectra () cover the Ca-triplet region ( nm) and span the complete time frame from the start of RAVE observations on 2003 April 12 to their completion on 2013 April 4. The sixth and final data release (DR6) is based on 518 387 observations of 451 783 unique stars and it contains the derived spectral classification and radial velocities for the RAVE targets. The data products of the release are obtained by using a suite of advanced reduction pipelines focusing on stellar atmospheric parameters, in particular purely spectroscopically derived stellar atmospheric parameters (effective temperature, surface gravity, and the overall metallicity), enhanced stellar atmospheric parameters inferred via a Bayesian pipeline using Gaia DR2 astrometric priors, and asteroseismically calibrated stellar atmospheric parameters for giant stars based on asteroseismic observations for 699 K2 stars. Furthermore, abundances of the elements Fe, Al, and Ni, as well as an overall ratio, obtained using a new pipeline based on the GAUGUIN optimization method that is able to deal with variable signal-to-noise ratios, are provided. The RAVE DR6 catalogues are complemented by orbital parameters and effective temperatures based on the infrared flux method. The RAVE spectra were taken using the multi-object spectrograph 6dF (6 degree fields) on the 1.2 m UK Schmidt Telescope of the Australian Astronomical Observatory (AAO). Each fibre has a diameter of 100 m (6.7in the sky) and can be placed accurately (to within 10 m, or 0.7) on star positions anywhere within the 6diameter field.
Catalogue cleaning and Join table
The catalogue has two identifiers: RAVEID (which is not unique in the catalogue and indicates a source) and RAVE_OBS_ID (which is unique in the catalogue and indicates different observations of a given source). Therefore, we choose to associate to each RAVEID the astrometry of the first observation collected, i.e. the coordinates of the RAVE_OBS_ID corresponding to the RAVE_OBS_ID1 field listed in ravedr6.dr6_repeats table. However, there are few sources (10), with different RAVEIDs, that are closer than 3.5 (i.e. less than half the fiber diameter). We treated such cases as suspected duplicates and use only one of them for cross-match calculations.
A convenience table is available that can be used to join RAVE DR6 catalogue with the cross-match results. The table links the external catalogue original sourceId (original_ext_source_id), which is the RAVE_OBS_ID, to the corresponding additional numerical identifier (ravedr6_oid). Both original_ext_source_id and ravedr6_oid are present in the cross-match output tables (ravedr6_best_neighbour and ravedr6_neighbourhood). In the case of the known multiple observation of the same source (same RAVEID, but different RAVE_OBS_ID and the few cases of suspected RAVE DR6 duplicates) different original_ext_source_id will correspond to the same ravedr6_oid.
According to the definition used in this work, RAVE DR6 is a sparse survey. In the cross-match algorithm RAVE DR6 is thus the leading catalogue. This means that counterparts for RAVE DR6 objects are searched for in Gaia. For this catalogue the special treatment to account for the small issues in Gaia astrometry, especially for bright stars, was applied.