The assembly of dynamically distinct stellar components: insights from cosmological simulations

by Katy Proctor (Stockholm University)

Friday 10 Oct 2025, 10:30 → 11:30 Europe/Stockholm

FC61 (AlbaNova Main Building)

Deep observations reveal that galaxies are surrounded by a faint, diffuse stellar component known as the intra-halo light (IHL). Often referred to as stellar haloes around galaxies and the intra-cluster light in clusters, the IHL is thought to originate largely from disrupted satellites, making it a key tracer of galaxy assembly. In this talk, I will present a dynamical decomposition method that separates the main structural components of simulated galaxies, which I use to study their present-day properties and formation pathways. I will show that while the IHL is typically dominated by accreted stars, contributions from stars formed in the central galaxy can be significant, with formation mechanisms that vary with galaxy mass. I will conclude by discussing the limitations of using the IHL to infer galaxy merger histories and highlight preliminary results from new simulations that probe these processes with higher resolution and improved physics.