From Newton to Einstein – N-body dynamics in galactic nuclei and SPH using new special hardware and astrogrid-D

The dynamics of galactic nuclei containing multiple supermassive black holes is modelled including relativistic dynamics. It is shown that for certain initial conditions there is no stalling problem for the relativistic coalescence of supermassive black hole binaries. This astrophysical application and another one using a smoothed particle hydrodynamics code are our first use cases on a new computer architecture using GRAPE and new MPRACE accelerator cards based on reconfigurable chips, developed in the GRACE project. We briefly discuss our science applications and first benchmarks obtained with the new hardware. Our present architecture still relies on the GRAPE special purpose hardware (not reconfigurable), but next generations will focus on new architectural approaches including custom network and computing architectures. The new hardware is embedded into national and international grid infrastructures.