The GALAH+ Survey: A New Library of Observed Stellar Spectra Improves Radial Velocities and Reveals Motions within M67

GALAH+ is a magnitude-limited survey of high resolution stellar spectra obtained by the HERMES spectrograph at the Australian Astronomical Observatory. Its third data release provides reduced spectra with new derivations of stellar parameters and abundances of 30 chemical elements for 584,015 dwarfs and giants, 88% of them in the Gaia magnitude range 11 =3 visits spanning more than a year. The combination of radial velocities from GALAH+ with distances and sky plane motions from Gaia enables studies of dynamics within streams and clusters. For example, we show that the open cluster M67 has a total mass of ~3300 Msun and seems to be slowly contracting and rotating. This is likely a consequence of a perturbation during the cluster's last passage through the Galactic disc ~40 Myr ago.