On the causal origin of properties of dark matter halos and galaxies
 

ABSTRACT

Large-cosmological simulations, such as Illustris-TNG or Horizon-AGN, allows to draw relations between the formation history of galaxies and their host haloes (number of mergers, formation time) and their properties (galaxy morphology, halo concentration). These relations are however statistical in nature, as no two galaxies share the same formation history. In this seminar, I will present an alternative approach to draw causal links instead of statistical ones. Indeed, by carefully modifying the initial conditions of cosmological simulations, one can control the subsequent formation of halos and galaxies in the simulation, thus allowing one to conduct controlled numerical experiments. Using this approach, I will present fundamental results on the origin of the angular momentum and concentration parameter of dark matter halos, before presenting results on the properties of galaxies, and in particular their spin.