Towards a Better Understanding of Dark Matter Halo Structures around Galaxies

Abstract

There is substantial evidence that the stars, dust, and gas visible in galaxies are enveloped in “halos†of unseen dark matter. The goal of this research is to explore the effects varying initial conditions have on final equilibrium distributions of simulated dark matter halo density and velocity, and to assess how well analytical models fit these data. In particular, we pay special attention to the velocity distributions of our models, something often overlooked in other studies. Eighty separate computer simulations representing dark matter halos were made under various initial conditions, involving two halo types and three variables. Analytical density and velocity models were fitted to the 80 halos, including de Vaucouleurs, Plummer, generalized Navarro- Frenk-White, and non-extensive thermodynamics models. Statistical chi-squared (χ2 ) tests, quantifying how well a model fits data, were applied. Relative χ2 values for each model were plotted, reflecting which analytical models performed best for various simulations.