Tracing Supermassive Black Holes in cosmological simulations.

Supermassive black holes (SMBHs) represent one of the most mysterious topics in modern astrophysics. The feedback from active galactic nuclei (AGN) fed by SMBHs has been proposed as a major cause of the regulation and extinction of star formation rates in massive galaxies. Cosmological hydrodynamical simulations are successful tools for investigating the evolution of galaxies in a cosmological context and due to the co-evolution of BHs and host galaxies, simulations must correctly include the effect of BHs. However, the introduction of BHs into simulations runs up against numerical limitations imposed by mass and spatial resolution asking for ad hoc sub-resolution techniques. Recently, new methods have been developed to reproduce the dynamical friction force that binds BHs at the centre of galaxies and drives the early stages of mergers. Accurate reconstruction of BH dynamics proves to be not only a necessary ingredient to recover the AGN feedback that influences structure growth, but also a powerful tool to fully exploit the new window offered by gravitational wave astrophysics for the study of the formation and evolution of cosmic structures.