PGI Fall Seminar Series| Keefe Mitman|Caltech| "Gravitational Waves in Numerical Relativity and the Importance of BMS Frames"


As was realized by Bondi, Metzner, van der Burg, and Sachs (BMS), the symmetry group of asymptotic infinity is not the Poincaré group, but an infinite-dimensional group called the BMS group. Because of this, understanding the BMS frame of the gravitational waves produced by numerical relativity is crucial for ensuring that analyses on such waveforms and comparisons with other waveform models are performed properly. Up until now, however, the BMS frame of numerical waveforms has not been thoroughly examined, largely because the necessary tools have not existed. In this talk, I will highlight new methods that have led to improved numerical waveforms; specifically, I will explain what the gravitational memory effect is and how it has recently been resolved in numerical relativity. Following this, I will then illustrate how we fix the BMS frame of numerical waveforms to perform much more accurate comparisons with either Post-Newtonian or Quasi-normal Mode models.