One expects that SMBHs in galactic nuclei should harbour both stars and gas. The former can be modelled as a star cluster while the latter most likely forms a disc around the central object. The evolution of mass and spin of the central SMBH depends crucially on the way mass is accreted through the disc, which, in turns, depends not only on the disc properties but also on the star-disc interaction.

People involved: Luca Naso, Rainer Spurzem, Peter Berczik, Gareth Kennedy; Hzi-Yu Schive, Harry Sun.