Comparing Amplitude and Phase Agreement Between Waveform Approximants for Binary Black Hole Observations.

In this study, we compare gravitational waveform models used to analyze binary black hole mergers observed by the LIGO/Virgo/Kagra gravitational-wave observatory network. We compare a range of approximants in the posterior parameter space (the recovered masses and spins) of specific observations, including a more asymmetric-mass binary black hole merger (GW190412) and a more equal-mass event such as GW150914. We compare approximants within various waveform families, such as IMRPhenom and EOBNR, while also comparing approximants in different families to one another. For each gravitational wave event and waveform comparison, we compute the amplitude and phase differences between the generated waveforms in the frequency domain. These findings provide insights into the strengths and limitations of various waveform models in different regions of parameter space, for example with varying mass ratio. Thereby contributing to our understanding of waveform accuracy for parameter estimation in gravitational wave astronomy.