Sub-halo Dynamics

Here at Yale I have also worked with Frank van den Bosch on investigating dark matter substructure in numerical simulations. Recently it has become clear the large cosmological simulations do not properly resolve sub-halo and they are prone to troublesome numerical artifacts. Therefore the detailed behavior of sub-halos in these large volume simulations shouldn’t be trusted! I was part of the team to create the DASH library which is a suite of high resolution simulations focused specifically on subhalloes to better understand theier numerics and dynamics.

Self-Friction

I lead a study exploring the effects of dynamical self-friction: when a sub-halo’s previously stripped material interacts with the still bound remnant causing it to lose angular momentum and decay in radius. This adds another complication to the already difficult process of modelling galaxy mergers. We have published these results in Miller et al. 2020. Self-friction always leads to orbital decay, sapping angular momentum from the subhalo. While we find that in general self-friction is a 10% effect compared to normal dynamical friction it is important for radial orbits close to their pericentric passage.