Including non-linear gravitational memory effects in intermediate-mass-ratio black hole inspiral waveform models

In this talk, I will examine the non-linear gravitational wave (GW) memory effect in Intermediate Mass Ratio Inspirals (IMRIs), a lasting change in spacetime caused by gravitational waves. This memory effect presents a distinctive signature, separate from typical GW oscillations. IMRI systems are effectively modeled using point-particle black hole perturbation theory, and recent efforts have produced accurate waveform models for mass ratios up to q=1000 and primary black hole spins between ±0.8. However, the non-linear memory effect is not included in the perturbation theory calculation, which involves numerically solving the Teukolsky equation. I will discuss the incorporation of non-linear memory effects into existing IMRI waveform models across this range of mass ratios and spins, along with comparisons and calibrations against numerical relativity data. These enhanced waveform models will be valuable for future GW studies where non-linear memory effects play a significant role.