Research: Computational Astrophysics

CITA's expertise and computing infrastructure continue to drive a strong analysis and simulation effort, including large scale parallel N-body and hydrodynamics, and numerical simulations of binary black holes.

Numerical Relativity

Numerical Relativity is concerned with solving Einstein's equations on computers in situations of astrophysical interest. Binary black hole simulations aiding gravitational wave detectors like LIGO are one key research area of CITA's numerical relativity group. Some research results are presented in the General Relativity section. Here we highlight some of the computational aspects involved:

Harald Pfeiffer, with collaborators at Cornell and Albuquerque further developed implicit time-stepping algorithms for Einstein's equations. In the latest paper (accepted to PRD), they deal with single black holes, where the implicit methods were able to take time-steps several 100--times larger than the Courant limit. These techniques have the -- --potential to speed up binary black hole simulations -- --significantly.

Abdul Mroue has continued to develop algorithms for evolving binary black holes on GPUs. For certain parts of the black hole evolution code, speed-ups in excess of a factor 10 have already been realized.

Abdul Mroue, in collaboration with the Numerical Relativity groups of Cornell and Caltech, has performed a largest set of binary black hole simulations worldwide. Apart of their large number (about 100 runs) these simulations are also of exquisite quality (far longer and more accurate than previous simulations). Once the data has been processed, these runs will represent an important community resource for the study of binary black hole systems, helping in particular to address how well LIGO can detect precessing black hole binaries.