Speaker
Description
One of the most striking things that we have learned about the Milky Way from Gaia data is the extent to which its disc has been disturbed. The way we describe and characterise this disturbance seems to depend on how we are looking at it. We can at least agree that the Milky Way’s disc is rippling up and down, and a prime suspect for this disturbance is the Sagittarius dwarf galaxy shaking the disc as it passed by some time ago.
In this talk I will focus primarily on the outer Milky Way disc, and show how this disturbance can be seen here. I will present new work on the Milky Way's warp which shows that the position and kinematics of stars in the warp are inconsistent with the picture of a simple precessing warp. I will also show how there is a break of the velocity distribution into two clumps: one rotating slower around the galactic centre and moving downwards, and one rotating faster and moving upwards. I will show how these behaviours are replicated in simulations of the impact of the Sagittarius dwarf on the Milky Way disc, and argue that these disturbances will allow us to conduct ’Galactic-seismology’ and determine the structure and history of the Milky Way with new clarity.
