Dynamical evolution of rotating dense stellar systems with embedded black holes

Abstract

The evolution of self-gravitating rotating dense stellar systems (e.g. globular clusters, galactic nuclei) with embedded black holes is investigated. The interaction between the black hole and the stellar component in differentially rotating flattened systems is analysed. The interplay between velocity diffusion resulting from relaxation and black hole star accretion is investigated, together with cluster rotation, using 2D+1 (20 in space and time) Fokker-Planck numerical methods. The models can reproduce the Bahcall-Wolf solution f E 1/4 (n r -7/4 ) inside the zone of influence of the black hole. Gravo-gyro and gravo-thermal instabilities cause the system to have a faster evolution, leading to shorter collapse times with respect to non-rotating systems. Angular momentum transport and star accretion support the development of central rotation on relaxation time-scales. We explore system dissolution as a result of mass loss in the presence of an external tidal field (e.g. for globular clusters in galaxies).