David A. Nichols (Physics) - University of Virginia
Title: Gravitational-wave memory effects from binary-black-hole mergers
Abstract: Over forty detections of binary-black-hole mergers were made during the first three observing runs of the LIGO and Virgo detectors. With this larger number of measurements of increasing accuracy, many of the remarkable predictions of general relativity for strongly curved, dynamical spacetimes will be able to be studied observationally. In this talk, I will discuss one class of strong-gravity phenomena, called gravitational-wave memory effects, which are predictions of general relativity that are most prominent in systems with high gravitational-wave luminosities, like binary black holes. Memory effects are characterized by changes in the gravitational-wave strain and its time integrals that persist after a transient signal passes by a detector. I will discuss the computation of these effects and the prospects for current and planned future gravitational-wave detectors to detect memory effects from black-hole mergers; in particular, there could be evidence for the memory effect in just a few years of advanced LIGO, Virgo, and KAGRA data at the detectors' design sensitivities. I will also discuss what observing gravitational-wave memory effects can teach us about the symmetries and conserved quantities around isolated systems like binary-black-hole mergers.