From Random Walks to Dark Matter Haloes

Who: Antonio Riotto (CERN & Padua)
When: Monday, March 15, 2010 at 14:15
Where: The CP³ meeting room

In the current cosmological theory large-scale structures grew via gravitational instability from small-amplitude density fluctuations generated in the very early Universe. Dark matter haloes condense out of these initial fluctuations. This process can be studied by N-body simulations, but it is important to be able to understand the results in simpler terms. We describe a method which is based on the path-integral
formulation of field theory to compute the dark matter distribution and is mapped into the so-called first-passage time problem of a random walk in the presence of a barrier. We show that the resulting halo mass function is in remarkable agreement with the existing simulations, without any ad hoc coefficients.