Presentation Archive

Studying Dark Matter Substructure with Globular Clusters

Jeremy Webb (University of Toronto)

May 23, 2019

Abstract: Leading cosmological models predict that the dark matter halos of galaxies are presently made up of a large number of sub-halos. While massive sub-halos take the form of satellite galaxies, the majority of the predicted sub-halo population remains unaccounted for as sub-halos do not contain luminous matter, challenging our understanding of dark matter and galaxy formation. Traditional methods for searching for substructure (modelling tidal streams, gravitational lensing) have been unable to agree on the current substructure composition of the Milky Way. I will discuss how globular clusters can be used to directly and indirectly compliment the search for dark matter substructure. The effect (or lack thereof) of dark matter substructure on globular cluster evolution can help constrain the properties of dark matter substructure and validate the use of tidal fields extracted from cosmological simulations when modelling cluster evolution. To this end, I will also a discuss the development of a new model for how clusters respond to tidal shocks. Furthermore, modelling the complete evolution of globular clusters to dissolution (and beyond) will demonstrate what stream properties can and cannot be used to study dark matter substructure as well. Finally I will discuss what streams can tell us about their progenitor clusters.