Study of eccentric binary black hole mergers using numerical relativity and an inspiral-merger-ringdown model

We study the phenomenology of non-spinning eccentric binary black hole (BBH) mergers using numerical relativity (NR) waveforms and EccentricIMR waveform model, as presented in Ref. Hinder: 2017sxy (Hinder, Kidder, and Pfeiffer, arXiv: 1709. 02007). This model is formulated by combining an eccentric inspiral, derived from a post-Newtonian (PN) approximation including 3PN conservative and 2PN reactive contributions to the BBH dynamics, with a circular merger model. A distinctive feature of EccentricIMR is its two-parameter treatment, utilizing eccentricity and mean anomaly, to characterize eccentric waveforms. We implement the EccentricIMR model in Python to facilitate routine use. We then validate the model against 35 eccentric NR waveforms obtained from both the SXS and RIT NR catalogs. We find that EccentricIMR model reasonably match NR data for eccentricities up to 0. 16, specified at a dimensionless reference frequency of x=0. 07, and mass ratios up to q=4. Additionally, we use this model as a tool for cross-comparing eccentric NR data obtained from the SXS and RIT catalogs. Furthermore, we explore the validity of a circular merger model often used in eccentric BBH merger modelling using both the NR data and EccentricIMR model. Finally, we use this model to explore the effect of mean anomaly in eccentric BBH mergers.