Speaker: Michel-Andrès Breton (LAM, Marseille)
Title: Propagating light through the large-scale structures of the Universe.
Abstract:
On the largest cosmic scales we assume the statistical isotropy and homogeneity of the matter density field. However, our knowledge comes mostly from observing the universe via messengers like photons which can be disturbed during their propagation, resulting in a distortion in our perception of the Universe. In order to extract cosmological information from observations, it is therefore mandatory to precisely model our Universe, from the formation of structures to the propagation of photons. During this talk I will discuss numerical methods to achieve both, emphasizing on the latter and presenting the ray-tracing code Magrathea, a powerful relativistic library to compute null geodesics and optimized for HPC. Directly integrating null geodesics enables a wide range of analysis beyond standard weak lensing and relies on less approximations. I will present several types of possible analyses, using Magrathea on large N-body simulations.