Special Universe Talk: Dark Matter Substructure and the Clustering Crisis

by Frank van den Bosch (Yale University)

Monday 17 Oct 2016, 15:00 → 16:00 Europe/Berlin

seminar room, ground floor (MIAPP building, Boltzmannstr. 2, Garching)

Hierarchical structure formation in a LambdaCDM cosmology gives rise to virialized dark matter halos that contain a wealth of subtructure. Dark matter subhalos are believed to host satellite galaxies, and their demographics is therefore directly linked to the small-scale clustering of galaxies. Frank will demonstrate a crisis in our understanding of this small scale clustering, and argue that it arises from numerical issues in cosmological simulations that are used to model subhalo demographics. He will present a detailed discussion of both physical and numerical effects that lead to subhalo disruption, and show that current simulations are unable to accurately resolve the dynamical evolution of dark matter substructure. Frank will end with a discussion of implications for our ability to do precision cosmology using clustering data on small, non-linear scales.