On gravitational-wave spectroscopy of massive black holes with the space interferometer LISA

TL;DR

This paper develops a formalism for detecting and analyzing ringdown gravitational waves from supermassive black holes with LISA, enabling black hole spectroscopy and tests of general relativity.

Contribution

It introduces a multi-mode formalism applicable to interferometric detectors for extracting black hole parameters and testing the no-hair theorem using LISA data.

Findings

LISA can detect ringdown signals with high signal-to-noise ratio.

Parameter estimation for black hole properties can be achieved with good accuracy.

Different modes of ringdown can be resolved to perform black hole spectroscopy.

Abstract

Newly formed black holes are expected to emit characteristic radiation in the form of quasi-normal modes, called ringdown waves, with discrete frequencies. LISA should be able to detect the ringdown waves emitted by oscillating supermassive black holes throughout the observable Universe. We develop a multi-mode formalism, applicable to any interferometric detectors, for detecting ringdown signals, for estimating black hole parameters from those signals, and for testing the no-hair theorem of general relativity. Focusing on LISA, we use current models of its sensitivity to compute the expected signal-to-noise ratio for ringdown events, the relative parameter estimation accuracy, and the resolvability of different modes. We also discuss the extent to which uncertainties on physical parameters, such as the black hole spin and the energy emitted in each mode, will affect our ability to do black hole spectroscopy.