Speaker
Description
Nuclear and globular star clusters (NSC and GC) are spectacular self-gravitating stellar systems in our Galaxy and across the Universe - in many respects. They populate disks and spheroids of galaxies as well as almost every galactic center. In massive elliptical galaxies NSCs harbor supermassive black holes, which might influence the evolution of their host galaxies as a whole. The evolution of star clusters is not only governed by the aging of their stellar populations and simple Newtonian dynamics. For increasing particle number, unique gravitational effects of collisional many-body systems begin to dominate the early cluster evolution. Direct N-body simulations are the most computationally expensive but also the most astrophysically advanced method to simulate GC and NSC evolution, using massively parallel supercomputers with GPU acceleration. While most objects in our simulations are sufficiently treated by using a combination of Newtonian dynamics and stellar astrophysics, it is observed that quite a number of compact binaries consisting of black holes or neutron stars forms and evolves. Their relativistic dynamics, including gravitational wave emission and final coalescence is modelled with Post-Newtonian dynamics in various degrees of approximation. Methods and problems to couple such relativistic objects to the global Newtonian simulations are discussed as well as selected published results. Latest unpublished data are shown including spin-orbit and spin-spin interactions. The new DRAGON-III project is introduced, which will use the same methods to model EMRI's and IMRI's in galactic nuclei.