Eccentric binary black hole surrogate models for the gravitational waveform and remnant properties: comparable mass, non-spinning case
Black holes are fascinating objects! They become more so when two of them merge. Merging black holes radiate energy in the form of gravitational waves (GWs). GWs then propagate intergalactic distances to reach Earth. Ground-based detectors operated by the Laser Interferometer Gravitational-Wave Observatory (LIGO) and Virgo are capable of detecting such signals. Detection of GWs can help us to understand the population of black holes, their evolutionary history, and even their surrounding environments.
GWs modeling efforts have mostly focused on quasi-circular binary black bole mergers. GWs detected by LIGO and Virgo so far are also consistent with binaries that have circularized. Binaries are expected to be eccentric if they are formed in dense globular clusters or galactic nuclei. Some scientists claimed the recent observation of GW190521 to be an eccentric one. The unavailability of faithful waveform models for eccentric binaries has made such analysis difficult. In this work, we have recently simulated 47 eccentric non-spinning numerical relativity (NR) waveforms for comparable mass binary black holes. Trained on those NR waveforms, we build a reduced-order eccentric surrogate waveform model which can provide fast and reliable eccentric waveforms. Our model is nearly as accurate as gravitational waveforms found through numerically solving the Einstein Equation, which requires supercomputers and may take weeks to months for a single computation depending on the complexity of the system. The model will aid both the detection and analysis of GW signals in the coming years.