Adding eccentricity to quasi-circular binary-black-hole waveform models.

The detection of gravitational-wave signals from coalescing eccentric binary black holes would yield unprecedented information about the formation and evolution of compact binaries in specific scenarios, such as dynamical formation in dense stellar clusters and three-body interactions. The gravitational-wave searches by the ground-based interferometers, LIGO and Virgo, rely on analytical waveform models for binaries on quasi-circular orbits. Eccentric merger waveform models are less developed, and only few numerical simulations of eccentric mergers are publicly available, but several eccentric inspiral models have been developed from the Post-Newtonian expansion. Here we present a novel method to convert any circular analytical merger model into an eccentric model. First, using numerical simulations, we investigate the additional amplitude and frequency modulations of eccentric signals that are not present in their circular counterparts. Subsequently, we identify suitable analytical descriptions of those modulations and interpolate key parameters from twelve numerical simulations designated as our training data set. This allows us to reconstruct the modulated amplitude and phase of any waveform up to mass ratio three and eccentricity 0.2. We find that the minimum overlap of the new model with numerical simulations is 0.984 over our test data set. A Python package pyrex easily carries out the computation of this method.