Akaxia is a Flatiron Research Fellow at the Center for Computational Astrophysics and a Future Faculty in the Physical Sciences Postdoctoral Fellow in the Princeton University Department of Physics. She will be visiting Yale December 8th through the 12th.
Title: Exploring solutions to the dwarf galaxy diversity problem
Abstract: Overwhelming observational evidence suggests that 85% of all matter in the Universe is dark matter (DM), a mysterious form of matter whose microscopic properties remain poorly constrained. The current, widely assumed paradigm of a collisionless, cold DM (CDM) and dark energy cosmology called LCDM agrees remarkably well with observational data on large scales, however non-linear, galactic scales have often challenged the LCDM paradigm. For example, numerical CDM-only simulations predict identical rotation curves for fixed dark matter halo mass yet observed dwarf galaxies exhibit diverse rotation curves. Numerical simulations which model complex galaxy formation (baryonic) physics may be the solution to the diversity of rotation curves problem, though previous CDM simulations with baryons have struggled to simultaneously reproduce the most steeply and slowly rising rotation curves, and compact and extended galaxies at fixed stellar mass. An alternative solution is dark matter self-interactions which collisionally thermalize dark matter particles and alter central halo densities. In this seminar, I will discuss a suite of high-resolution cosmological zoom-in simulations aimed to consistently explore dwarf galaxy diversity in CDM and multiple models of self-interacting dark matter with baryons. We find CDM and low cross-section SIDM simulations with baryons both produce steeply and slowly rising rotation curves, prompting further exploration of galactic properties which may distinguish the two DM models.
