When:
Tuesday, October 31, 2017
4:00 PM - 5:00 PM CT
Where: Technological Institute, F160, 2145 Sheridan Road, Evanston, IL 60208 map it
Audience: Faculty/Staff - Student - Public - Post Docs/Docs - Graduate Students
Contact:
Pamela Villalovoz
(847) 491-3644
Group: Physics and Astronomy Astrophysics Seminars
Category: Academic
Title: Dark Matter Substructure: Cosmological Treasure Trove or a Pandora's Box?
Speaker: Frank van den Bosch, Yale University
Host: Sarah Wellons
Abstract: Hierarchical structure formation in a LCDM cosmology gives rise to virialized dark matter halos that contain a wealth of subtructure. Being able to accurately predict the abundance and demographics of dark matter subhaloes is of paramount importance for many fields of astrophysics: gravitational lensing, galaxy evolution, and even constraining the nature of dark matter. Dark matter substructure is subject to tidal stripping and tidal heating, which are highly non-linear processes and therefore best studied using numerical N-body simulations. Unfortunately, as I will demonstrate, state-of-the-art cosmological simulations are unable to adequately resolve the dynamical evolution of dark matter substructure. They suffer from a dramatic amount of artificial subhalo disruption as a consequence of both inadequate force softening and discreteness noise amplification in the presence of a tidal field. I present criteria that can be used to assess the reliability of subhaloes in numerical simulations, discuss implications for a variety of astrophysical applications, and briefly suggest potential ways forward.
Keywords: Physics, Astronomy, Astrophysics