Modelling gravitational waves from eccentric binary black hole mergers

Bonino, Alice ORCID: 0000-0001-6502-284X (2025). Modelling gravitational waves from eccentric binary black hole mergers. University of Birmingham. Ph.D.

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Abstract

The detection of gravitational waves from the coalescence of compact binary objects has provided a powerful tool to probe the origin of such systems and inferring their properties. Although binary systems are expected to circularise their orbit through gravitational wave emission, they can still retain a significant degree of orbital eccentricity when entering the sensitivity band of gravitational wave detectors. Orbital eccentricity is considered a key tracer for constraining the formation pathways and dynamical evolution of binary systems. In order to reliably measure eccentricity in gravitational wave signals, it is crucial to develop accurate waveform models and routines to measure eccentricity from the data. In recent years, considerable effort has been invested in incorporating eccentricity into waveform models. However, substantial work remains to improve the accuracy of eccentric waveform models. In this thesis we first perform parameter estimation of a gravitational wave event and validate the efficacy of an effective-one-body model in distinguishing between circular and eccentric signals as well as explore the correlations between eccentricity and other parameters characterising the binary. We then present a robust pipeline to reliably measure eccentricity from gravitational wave data and a map between eccentricity evolutions in numerical relativity and effective-one-body waveforms. Finally, we present comparisons between numerical relativity and effective-one-body quantities and establish a method enabling direct comparison of fluxes and energetics for eccentric binaries in the comparable mass regime that can be used as a baseline for future studies.

Type of Work:

Thesis (Doctorates > Ph.D.)

Award Type:

Doctorates > Ph.D.

Supervisor(s):