Thanks for the memory: measuring gravitational-wave memory in the first LIGO/Virgo gravitational-wave transient catalog

TL;DR

This paper develops a Bayesian method to detect gravitational-wave memory in LIGO/Virgo data, applies it to initial observations, and predicts future detection prospects with more data and improved sensitivity.

Contribution

It introduces a novel Bayesian framework for gravitational-wave memory detection and estimates the observation count needed for definitive detection.

Findings

No memory detected in initial data, consistent with expectations.

Approximately 2000 binary black hole observations could enable definitive detection.

Memory detection is likely in the early A+/Virgo+ era.

Abstract

Gravitational-wave memory, a strong-field effect of general relativity, manifests itself as a permanent displacement in spacetime. We develop a Bayesian framework to detect gravitational-wave memory with the Advanced LIGO/Virgo detector network. We apply this algorithm on the ten binary black hole mergers in LIGO/Virgo's first transient gravitational-wave catalog. We find no evidence of memory, which is consistent with expectations. In order to estimate when memory will be detected, we use the best current population estimates to construct a realistic sample of binary black hole observations for LIGO/Virgo at design sensitivity. We show that an ensemble of $\mathcal{O}(2000)$ binary black hole observations can be used to find definitive evidence for gravitational-wave memory. We conclude that memory is likely to be detected in the early A+/Virgo+ era.