Computations of black-hole quasinormal modes in dynamical Chern-Simons gravity using METRICS

Detections of gravitational waves allow us to probe rich fundamental physics, including the validity of general relativity in the strong field regime. But to fully test general relativity, it will be beneficial to understand how various beyond Einstein extensions to general relativity affect gravitational-wave emission by compact binaries. While we have some understanding regarding the effects of the inspiral phase, the effects on the ringdown phase remain largely unexplored. Previously, we applied Metric pErTuRbations wIth speCtral methodS (METRICS) to compute the quasinormal-mode frequencies of black holes in a popular beyond Einstein extension, scalar-Gauss-Bonnet gravity. In this talk, I will discuss the latest progress in applying METRICS to dynamical Chern-Simons gravity, another well-motivated beyond-Einstein extension. If possible, I will also show preliminary results of ringdown-assisted gravitational-wave tests of these two beyond-Einstein extensions.