##### Department of Mathematics,

University of California San Diego

****************************

### Center for Computational Mathematics Seminar

## Harald Pfeiffer

#### Dept of Physics, Caltech

## Binary black hole simulations and implicit time-stepping

##### Abstract:

Numerical simulations of black hole binaries have made tremendous progress over the last years. The usefulness of such simulations is limited by their tremendous computational cost, which ultimately results from a separation of time-scales: Emission of gravitational radiation drives the evolution of the binary toward smaller separation and eventual merger. The time-scale for inspiral is far longer than the dynamical time-scale of each black hole. Therefore, the currently deployed explicit time-steppers are severely limited by Courant instabilities. Implicit time-stepping algorithms provide an obvious route around the Courant limit, thus offering a tremendous potential to speed up the simulations. However, the complexity of Einstein's equations make this a highly non-trivial endevour. This talk will first present a general overview of the status of Black Hole simulations, followed by a status report on the ongoing work aimed at implementing modern implict/explicit (IMEX) evolution schemes for Einstein's equations.

Host: Li-Tien Cheng

### April 21, 2009

### 11:00 AM

### AP&M 2402

****************************