Speaker
Description
The gravitational-wave (GW) memory effect is a prediction of general relativity, characterized by a permanent change in spacetime geometry. Although it has not yet been observed, next-generation detectors such as the Einstein Telescope (ET) and the Laser Interferometer Space Antenna (LISA) are expected to provide the sensitivity required for its first detection. GW memory comprises two distinct contributions: the nonlinear memory, generated by the self-interaction of GWs, and the linear memory, originating from the anisotropic emission of matter and radiation associated with astrophysical transients. In this talk, I will show how we quantify both nonlinear and linear memory contributions produced during binary neutron star mergers, including those from GWs, gamma-ray bursts (GRB), afterglows, neutrinos, dynamical and disk-wind ejecta, and kilonova emission. I will then discuss their detectability with ET and LISA through two specific applications. First, I will focus on the multi-messenger event GW170817-GRB 170817A-AT2017gfo, for which we find that the combined memory signal would have been detectable by ET with a signal-to-noise ratio of 10.7, dominated by the nonlinear memory. Second, I will present our assessment of GRB memory across a synthetic population, showing that only extreme-energy and favorably oriented configurations could produce a detectable signal.