RSAA Colloquia / Seminars / Feast-of-Facts: Tuesday, 26 November 2019, 11:00-12:00; Duffield Lecture Theatre


Ortwin Gerhard

"Structure and Dynamics of the Barred Milky Way"

The Milky Way’s central box/peanut bulge together with the planar long bar are estimated to contain one third of our Galaxy’s stars. Dynamical models based on star count and radial velocity data have also set limits on the dark matter mass in the bulge, and determined a fairly large corotation radius of ~6kpc, which suggests that the Galactic bar will be important also for understanding solar neighbourhood dynamics. I will discuss the dynamics of the Milky Way’s barred components, including recent work on the pattern speed based on VVV and Gaia proper motions. I will also describe new results on stellar metallicities in the long bar, and on isolating the Galactic spiral arms in Gaia DR2.