Kristopher Youakim (Stockholm University): Galactic archaeology in the stellar halo of the Milky Way

Thursday 14 Sept 2023, 14:00 → 15:00 Europe/Stockholm

101190Å (Ångströmlaboratoriet)

Title: Galactic archaeology in the stellar halo of the Milky Way 
Speaker: Kristopher Youakim
Affiliation: Stockholm University
Time: Thursday 14 September 2023, 1400 to 1500
Location: 101190Å

Abstract: The Milky Way Galaxy is a prime place to study galaxy structure and evolution, since our Galaxy and its immediate surroundings are currently the only place where we can obtain detailed observations of individual stars. According to the Lambda-CDM framework, galaxies are built-up in a bottom-up fashion, with smaller galaxies merging over time to create larger ones. If this is correct, it implies that stars in the halo of our Galaxy should still exhibit chemical and kinematic signatures from these past and ongoing merger events.

In this talk, I will show how detailed observations of large numbers of stars in our Galaxy from the ESA Gaia satellite and large scale spectroscopic surveys are facilitating the discovery and characterization of substructures and past accretion events like never before. I will also discuss my current work using unsupervised machine learning to search for tidal debris ejected from the nearby star cluster Omega Centauri, which allows us to study its interaction with the Milky Way and place constraints on Omega Cen's mass and time of accretion.