MSc Thesis Defence: Dynamical Tidal Deformation of a Body in General Relativity, Without Modes

MSc Candidate

Tristan Pitre

Abstract

In the context of a neutron star in a binary system, the emitted gravitational waves are influenced by the tidal deformation caused by its companion. Initially, during the early inspiral, the interaction is described by static tides. However, as the process progresses, the growing effect of dynamical tides becomes evident. The existing literature employs a spectral approach linked to the star's normal modes, grounded in Newtonian physics, which poses challenges when extending to general relativity. This study introduces a mode-less description applicable to both Newtonian and relativistic mechanics. Assuming a slowly evolving tidal field and utilizing a time-derivative expansion, the characterization of tidal deformation involves both static and dynamic Love numbers. Computational results for polytropic models in both Newtonian gravity and general relativity are provided. To overcome the initial limitations of this new approach, where the slow-evolving tidal field approximation prevents the capturing of resonance in dynamical tides, this study introduces an extension of the time-derivative expansion with the goal of achieving accuracy comparable to the f-mode truncation in the mode representation.

Examination Committee

• Dr. Robert Wickham, Chair
• Dr: Eric Poisson, Advisor
• Dr. Huan Yang, Advisory Committee
• Dr. Liliana Caballero, Graduate Faculty