Improved and new RVs for the GALAH+ survey

Its third data release provides reduced spectra with new derivations of stellar parameters and abundances of 30 chemical elements for 584015 dwarfs and giants, 88 per cent of them in the Gaia magnitude range 11 < G < 14. Here, we use these improved values of stellar parameters to build a library of observed spectra which is useful to study variations of individual spectral lines with stellar parameters.

This and other improvements are used to derive radial velocities with uncertainties which are generally within 0.1 km/s or ~25 per cent smaller than in the previous release. Median differences in radial velocities measured here and by the Gaia DR2 or APOGEE DR16 surveys are smaller than 30 m/s, a larger offset is present only for Gaia measurements of giant stars. We identify 4483 stars with intrinsically variable velocities and 225 stars for which the velocity stays constant over => 3 visits spanning more than a year.