Testing general relativity and informing astrophysics with gravitational waves

In the past decade, we have detected hundreds of gravitational waves, advancing our understanding of the Universe and its governing laws. In this talk, I will present the theoretical models and data analysis tools I have developed for interfacing gravitational-wave observations with fundamental physics and astrophysical theories. First, I will describe my work on linear and nonlinear black hole ringdown modeling and explain how it connects to the recently announced detection of ringdown quasinormal modes in GW250114. Second, I will discuss my work on diffraction lensing of gravitational waves by minihalos and present preliminary results for the new event GW231123. Third, I will present my work on the development and applications of the IAS gravitational-wave search pipeline. I will also describe ongoing work as well as future projects I would like to work on at the Institute.