Adding Gravitational Memory to Waveform Catalogs using BMS Balance Laws

Understand

Accurate models of gravitational waves from merging binary black holes are crucial for detectors to measure events and extract new science.

• One important feature that is currently missing from the Simulating eXtreme Spacetimes (SXS) Collaboration's catalog of waveforms for merging black holes, and other waveform catalogs, is the gravitational memory effect: a persistent, physical change to spacetime that is induced by the passage of transient radiation.
• We find, however, that by exploiting the Bondi-Metzner-Sachs (BMS) balance laws, which come from the extended BMS transformations, we can correct the strain waveforms in the SXS catalog to include the missing displacement memory.
• Our results show that these corrected waveforms satisfy the BMS balance laws to a much higher degree of accuracy.