Nonlinear quasinormal mode detectability with next-generation gravitational wave detectors

Understand

In the aftermath of a binary black hole merger event, the gravitational wave signal emitted by the remnant black hole is modeled as a superposition of damped sinusoids known as quasinormal modes.

• While the dominant quasinormal modes originating from linear black hole perturbation theory have been studied extensively in this post-merger "ringdown" phase, more accurate models of ringdown radiation include the nonlinear modes arising from higher-order perturbations of the remnant black hole spacetime.
• We explore the detectability of quadratic quasinormal modes with both ground- and space-based next-generation detectors.
• We quantify how predictions of the quadratic mode detectability depend on the quasinormal mode starting times.