Cracking Gravitational Wave Multiple Ringdown Modes in Space

TL;DR

This paper introduces a fast, scalable analysis pipeline for detecting multiple gravitational wave ringdown modes from black holes in space-based detectors, enhancing future astrophysical studies.

Contribution

It develops and validates FIREFLY, a novel acceleration algorithm, for efficient multi-mode ringdown analysis compatible with space-borne detector data.

Findings

Achieves a ~200-fold speedup in analyzing simulated multi-mode ringdown signals.

Demonstrates compatibility of FIREFLY with time-delay interferometry observables.

Provides a scalable approach for multi-mode analysis in space-based gravitational wave detection.

Abstract

Ringdown signals from perturbed black holes (BHs) offer a clean window into BH spacetime, strong-field gravity, and fundamental physics. Presently the quasi-normal modes of stellar-mass BH ringdowns have been successfully extracted in the ground-based gravitational wave (GW) observations. Looking ahead, the future space-borne observatories will listen to the ringdowns from massive BH binary coalescences more loudly and resolve multiple modes to unprecedented precision, which calls for efficient approaches to mitigate the sharply increasing computational burden. We develop a practical ringdown analysis pipeline for space-borne detectors by implementing FIREFLY, a novel acceleration algorithm validated in ground-based detectors, and for the first time demonstrate its compatibility and effectiveness with the time-delay interferometry (TDI) observables. With high fidelity, we achieve a $\sim 200$-fold speedup for a simulated ringdown signal including six modes, providing a viable and scalable route for multi-mode ringdown analysis in the space context. This new approach has sound statistical interpretation and is extensible to other GW sources in band.