Dynamical heating across the Milky Way disc

The high [{alpha}/Fe] disc component's flat AVRs and constant {sigma}_z_/{sigma}_R_ clearly indicate an entirely different heating history. Outer disc populations also have flatter radial AVRs than those in the inner disc, likely due to the waning effect of spiral arms. Our detailed measurements of AVRs and {sigma}_z_/{sigma}_R_ across the disc indicate that low [{alpha}/Fe], inner disc (R~<10kpc) stellar populations are likely dynamically heated by both giant molecular clouds and spiral arms, while the observed trends for outer disc populations require a significant contribution from another heating mechanism such as satellite perturbations.

We also find that outer disc populations have slightly positive mean vertical and radial velocities likely because they are part of the warped disc.