Galaxy-scale challenges and alternatives to cold dark matter

Cold-dark-matter cosmology explains much of the large-scale Universe, yet galaxy observations expose persistent tensions. This seminar examines baryonic scaling relations, halo profiles, diverse rotation curves, satellite planes, galactic bars and gas content. It asks whether better modelling of galaxy formation can resolve these discrepancies or whether different dark-matter properties or modified gravity are needed. Warm, ultralight and self-interacting dark matter are considered alongside the new questions each alternative raises.