GROOVHY: Gravitational radiation from black holes’ hyperbolic mergers

• Applicant: Professor Dr. Sebastiano Bernuzzi
• Subject Area: Nuclear and Elementary Particle Physics, Quantum Mechanics, Relativity, Fields ; Astrophysics and Astronomy
• Term: since 2023
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 523180871

Gravitational-wave observations of binary black holes (BBH) started in 2015 and prompted unprecedented tests of black-hole physics and of strong gravity in the high-frequency regime. They unveiled the existence of a diverse population of stellar-mass BBH that promises to clarify the astrophysical origin of these binaries and, at the same time, to observationally explore the rich binary dynamics predicted by general relativity. Hyperbolic BBH mergers, corresponding to binaries in Newtonian hyperbolic or parabolic orbits that become bound due to the emission of gravitational radiation, are one of the open challenges in gravitational-wave astronomy. The detection of these events can be a smoking gun for astrophysical investigations of black-hole formation and dynamics in galactic nuclei and high-density clusters. The key requirement for these BBH observations is the availability of accurate waveform templates including the merger regime that are currently missing. GROOVHY's goal is to design the first faithful and ready-to-use gravitational waveform model for the detection and parameter estimation of hyperbolic black hole mergers. The project is prompted by the observation of GW190521, a candidate first-detection of dynamical encounter, and timely addresses an open problem in waveform modeling in preparation to the large amount of gravitational-wave transients expected in the near future. GROOVHY develops and combines an effective-one-body approach to the two-body dynamics with new numerical relativity and test-mass perturbative simulations to obtain a robust prediction of the merger waveform from scattering, multiple encounters and zoom-whirls, and direct capture events. GROOVHY also explores full Bayesian inference of hyperbolic merger events to demonstrate readiness for matched filtering analyses. GROOVHY consolidates a new research effort in our waveform modeling research and exploits unique in-house expertise in numerical relativity, perturbation theory, analytical relativity and Bayesian data analysis. The project starts from recent breakthroughs in the analytical modeling of hyperbolic mergers and leverages on state-of-art techniques developed in Jena as part of a continued long-standing efforts in numerical general relativity. The expected advances to the state-of-art in waveform modeling will be put to best use thank to the team's participation to LIGO-Virgo-Kagra and LISA activities. The project will thus support national and international research at the highest possible level.

• DFG Programme: Research Grants
• International Connection: Italy, Spain
• Cooperation Partners: Professor Dr. José Antonio Font; Professorin Dr. Michela Mapelli; Dr. Alessandro Nagar