Spectroscopy of Kerr black holes with Earth- and space-based interferometers

TL;DR

This paper evaluates the capabilities of current and future gravitational-wave interferometers to test the Kerr black hole hypothesis through gravitational spectroscopy, highlighting the importance of advanced detectors for high-redshift observations.

Contribution

It provides a comprehensive analysis of the detection prospects for Kerr black hole spectroscopy across different interferometer classes and redshift ranges.

Findings

Voyager-class detectors are needed for Kerr tests.

Einstein Telescope could routinely perform these tests locally.

Space-based detectors like eLISA can test high-redshift black holes.

Abstract

We estimate the potential of present and future interferometric gravitational-wave detectors to test the Kerr nature of black holes through "gravitational spectroscopy," i.e. the measurement of multiple quasinormal mode frequencies from the remnant of a black hole merger. Using population synthesis models of the formation and evolution of stellar-mass black hole binaries, we find that Voyager-class interferometers will be necessary to perform these tests. Gravitational spectroscopy in the local Universe may become routine with the Einstein Telescope, but a 40-km facility like Cosmic Explorer is necessary to go beyond $z\sim 3$. In contrast, eLISA-like detectors should carry out a few - or even hundreds - of these tests every year, depending on uncertainties in massive black hole formation models. Many space-based spectroscopical measurements will occur at high redshift, testing the strong gravity dynamics of Kerr black holes in domains where cosmological corrections to general relativity (if they occur in nature) must be significant.