Testing Gravitational Memory Generation with Compact Binary Mergers

TL;DR

This paper explores the potential of current and future gravitational wave detectors to measure gravitational memory effects from binary mergers, testing predictions of General Relativity and probing neutron star properties.

Contribution

It introduces a phenomenological model for memory waveforms from neutron star mergers and assesses their detectability with third-generation detectors, linking memory to neutron star equations of state.

Findings

Third-generation detectors can easily rule out isotropic memory distribution hypotheses.

Memory measurement from neutron star mergers can distinguish between different neutron star equations of state.

Current detectors face challenges in measuring gravitational memory effects.

Abstract

Gravitational memory is an important prediction of classical General Relativity, which is intimately related to asymptotic symmetries at null infinity and the so-called soft graviton theorem first shown by Weinberg. For a given transient astronomical event, the angular distributions of energy and angular momentum flux uniquely determine the displacement and spin memory effect in the sky. We investigate the possibility of using the binary black hole merger events detected by Advanced LIGO/Virgo to test the relation between source energy emissions and gravitational memory measured on earth, as predicted by General Relativity. We find that while it is difficult for Advanced LIGO/Virgo, one-year detection of a third-generation detector network will easily rule out the hypothesis assuming isotropic memory distribution. In addition, we have constructed a phenomenological model for memory waveforms of binary neutron star mergers, and use it to address the detectability of memory from these events in the third-generation detector era. We find that measuring gravitational memory from neutron star mergers is a possible way to distinguish between different neutron star equations of state.