Résumé / Abstract Seminaire_IAP
« Dark Matter Dynamics »

Tom Abel
chair Institut Lagrange - Stanford University (Stanford, Etats-Unis d'Amérique)

To the best of our knowledge dark matter is a relatively cold collisionless fluid. Gravity is likely the only relevant force acting on it and determining its large scale dynamics. The non-linear behavior of this fluid is well ordered in phase space which appears quite complicated when projected to its three spatial coordinates. As the fluid evolves more and more caustics form and inside dark matter halos an extraordinary large number of streams can be found crossing at individual points. After introducing some of the general constraints we have on dark matter I will describe a novel approach to collisionless fluid dynamics which allows us to measure and describe collisionless fluid dynamics at unprecedented fidelity. The new approach also leads naturally to new numerical algorithms that overcome some of the major shortcomings of the standard N-body technique used for decades. These new methods allow us to give dark matter halo mass functions in models with a small scale perturbation cut-off such as in warm dark matter models. They also enable us to study in detail phase space mixing during the relaxation of dark matter halos over time.
vendredi 21 juin 2013 - 11:00
Amphithéâtre Henri Mineur, Institut d'Astrophysique de Paris
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