Physics Colloquium: Dr. Liliya Williams, University of Minnesota


Location: 118 Nieuwland Science Hall (View on map )

Dark Matter Halos from First Principles

Dr. Liliya Williams
University of Minnesota

The evolution and equilibrium structure of dark matter halos, which host galaxies and clusters of galaxies, has been extensively studied using N-body simulations over the past couple of decades. However, gaining a theoretical understanding of these structures has been more challenging. A decade ago we showed that the equilibrium structure of dark matter halos can be obtained using statistical mechanics, and the principle of maximum entropy. This model, DARKexp, provides very good fits to all averaged properties of N-body simulated halos: the density and velocity dispersion as a function of distance from the center, and the energy distribution of particles. In this talk I will extend those results and define a non-equilibrium functional---a type of free energy, or entropy---which is maximized for DARKexp, and which increases monotonically during the evolution towards equilibrium for idealized collisionless self-gravitating systems. 

Hosted by Prof. Howk

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