Colloquium – Leandro e Silva – Co-formation of the Milky Way’s thin and thick discs

Speaker: Dr. Leandro Beraldo e Silva (University of Michigan)

Title: Co-formation of the Milky Way’s thin and thick discs

Abstract:

Thin disc stars are younger than thick disc stars on average, and some models predict the thin disc to start forming only after the thick disc has formed, around 10 Gyr ago. According to these sequential scenarios, no significant old thin disc population should exist. In this talk, I will show recent observational evidence for the presence, in the MW, of an old thin disc population. I will discuss how the observed trends disfavour sequential scenarios but can be nicely accommodated in a scenario where the early MW had massive gas clumps with high star formation. Incidentally, I will also show evidence, in the MW, for radial migration in both thin and thick disc populations.