Resolving Gravitational Memory in Numerical Relativity using Cauchy-characteristic Extraction*

Although gravitational memory was realized in the 1970s, numerical simulations of binary black hole mergers have been unable to resolve this phenomenon until now. We show that by using Cauchy-characteristic extraction (CCE) to extract waveforms in simulations produced by SXS's Spectral Einstein Code, we can accurately resolve the gravitational memory. We present results for memory in simulations with a variety of mass ratios and spins. We also discuss the measurability of memory for both LIGO and LISA.