Gravity Seminars

Accurate characterization of gravitational wave signals from binary black hole (BBH) mergers require efficient models for the waveform and remnant quantities. While we have accurate models for quasi-circular BBH mergers, modelling eccentric binaries is still in its nascent stage. Using both numerical relativity (NR) and black hole perturbation theory (BHPT), we study the phenomenology of eccentric BBH waveforms. We present convincing evidence that the waveform phenomenology in eccentric BBH mergers is significantly simpler than previously thought. We find that the eccentric modulations in the amplitudes and frequencies in different spherical harmonic modes are all related and can be modeled using a single time series modulation. Using this universal eccentric modulation, we provide a model named gwNRHME to seamlessly convert a multi-modal (i.e with several spherical harmonic modes) quasi-circular waveform into multi-modal eccentric waveform if the quadrupolar eccentric waveform is known. This reduces the modelling complexity of eccentric BBH mergers drastically as we now have to model only a single eccentric modulation time-series instead of modelling the effect of eccentricity in all modes. We use gwNRHME to include eccentricity in current NR surrogate waveform models for quasi-circular mergers. Additionally, we discuss efforts in building dedicated surrogate models for eccentric BBH mergers using both NR and BHPT.