Dark matter and Galaxy formation

The "standard" model of cold dark matter LCDM is today the best to account for the formation of large-scale structures of the universe. However, there remain unsolved problems at the scale of galaxies. The distribution of baryons and dark matter in galaxies predicted by numerical simulations is far from what is observed. The model predicts a large excess of dark matter in galaxies, and a large number of satellites, with orders of magnitude discrepancy with observations. I will discuss how baryonic physics (Star Formation and AGN feedback) confronted to observations can constrain the nature of dark matter. Alternative models with modified gravity will also be discussed.