Title: Weighing the Solar Neighborhood while Embracing Disequilibrium Features

Speaker: Dr. Haochuan Li (Queen’s University)

Time: 14:00pm, September 6, 2023

Location: 3-402, PMO Xianlin Campus

Abstract: In early stages of Galactic Dynamics, it was assumed that the Milky Way was in dynamical equilibrium and that the Solar Neighborhood stars had separable in-plane and vertical motions. However, neither assumptions are exactly true. The unprecedented sample size brought by the Gaia space telescope sparked the novel approach of fitting the potential and distribution function simultaneously. With this approach, we measured the matter distribution profile and the distribution of Solar Neighborhood stars simultaneously, in both the 1D vertical phase space and the complete 6D phase space. The fitting residuals revealed well-known disequilibrium features. By plotting them in frequency-angle coordinates, we were able to determine the age of perturbation that lead to the observed features.