Space-borne Interferometers to Detect Thousands of Memory Signals Emitted by Stellar-mass Binary Black Holes

TL;DR

This paper proposes using space-borne interferometers like DECIGO to detect gravitational memory signals from stellar-mass binary black holes, predicting over 2,000 detections in 5 years, which could advance fundamental physics and astrophysics.

Contribution

It introduces a method to detect gravitational memory signals from stellar-mass black holes using space interferometers, demonstrating their potential to outperform ground-based detectors in this domain.

Findings

DECIGO can detect approximately 2,036 memory signals over 5 years.

Strong memory signals are within DECIGO's bandwidth due to abundant stellar-mass BBHs.

Space interferometers may detect smaller mass binary signals more effectively than traditional ground-based detectors.

Abstract

The gravitational memory effect manifests gravitational nonlinearity, degenerate vacua, and asymptotic symmetries; its detection is considered challenging. We propose using the space-borne interferometer to detect memory signals from stellar-mass binary black holes (BBHs), typically targeted by ground-based detectors. We use DECIGO detector as an example. Over 5 years, DECIGO is estimated to detect $\sim$2,036 memory signals (SNRs $>$3) from stellar-mass BBHs. Simulations used frequency-domain memory waveforms for direct SNR estimation. Predictions utilized a GWTC-3 constrained BBH population model (Power Law + Peak mass, DEFAULT spin, Madau-Dickinson merger rate). The analysis used conservative lower merger rate limits and considered orbital eccentricity. The high detection rate stems from strong memory signals within DECIGO's bandwidth and the abundance of stellar-mass BBHs. This substantial, conservative detection count enables statistical use of the memory effect for fundamental physics and astrophysics. DECIGO exemplifies that space interferometers may better detect memory signals from smaller mass binaries than their typical targets. Detectors in lower frequency bands are expected to find strong memory signals from $\sim 10^4 M_\odot$ binaries.