Optimizing LIGO with LISA forewarnings to improve black-hole spectroscopy

TL;DR

This paper proposes using LISA forewarnings to optimize LIGO's sensitivity, significantly enhancing black-hole spectroscopy by enabling targeted tuning and improving tests of black hole physics.

Contribution

It introduces a method to leverage LISA's early warnings to optimize LIGO's configurations for better black-hole spectroscopy results.

Findings

Optimized configurations can double the effectiveness of black-hole spectroscopy.

Narrowband tuning improves sensitivity at specific ringdown frequencies.

LISA forewarnings enable proactive LIGO operation adjustments.

Abstract

The early inspiral of massive stellar-mass black-hole binaries merging in LIGO's sensitivity band will be detectable at low frequencies by the upcoming space mission LISA. LISA will predict, with years of forewarning, the time and frequency with which binaries will be observed by LIGO. We will, therefore, find ourselves in the position of knowing that a binary is about to merge, with the unprecedented opportunity to optimize ground-based operations to increase their scientific payoff. We apply this idea to detections of multiple ringdown modes, or black-hole spectroscopy. Narrowband tunings can boost the detectors' sensitivity at frequencies corresponding to the first subdominant ringdown mode and largely improve our prospects to experimentally test the Kerr nature of astrophysical black holes. We define a new consistency parameter between the different modes, called $\delta {\rm GR}$, and show that, in terms of this measure, optimized configurations have the potential to double the effectiveness of black-hole spectroscopy when compared to standard broadband setups.