Substructure at High Speed II: The Local Escape Velocity and Milky Way Mass with Gaia DR2

Understand

Measuring the escape velocity of the Milky Way is critical in obtaining the mass of the Milky Way, understanding the dark matter velocity distribution, and building the dark matter density profile.

• In Necib $\&$ Lin (2021), we introduced a strategy to robustly measure the escape velocity.
• Our approach takes into account the presence of kinematic substructures by modeling the tail of the stellar distribution with multiple components, including the stellar halo and the debris flow called the Gaia Sausage (Enceladus).
• In doing so, we can test the robustness of the escape velocity measurement for different definitions of the "tail" of the velocity distribution, and the consistency of the data with different underlying models.