AstroWaveforms: Decoding the astrophysics of black hole binaries in individual gravitational wave signals.

The study of “environmental effects” (EEs) offers the unique prospect to extract astrophysical information from individual gravitational wave (GW) signals, by modelling perturbations to the vacuum emission of binary sources. Cutting-edge numerical simulations indicate that a range of complex and previously un-modelled EEs should arise in binary systems subject to perturbative forces, due to e.g. Roemer delays, tidal fields, migration in gas, stochastic accretion, resonances in neutron star interiors. Accessing this rich astrophysical information encoded in GW signals requires entirely new models of EEs, able to characterise unique GW signatures from a range of physical mechanisms and astrophysical environments. As a Marie Curie Fellow at the NBIA, I will resolve this issue by developing a novel model for EEs based on a Fourier decomposition of astrophysical perturbative forces, and create a modular Python package to implement the model in state-of-the-art waveform templates. I will use the latter to perform first-of-their-kind parameter inference studies, demonstrating how EEs can be harnessed to reveal the physics of BH environments and distinguish between binary formation pathways. The completion of the AstroWaveforms project will result in a new state-of-the-art in the modelling of EEs, as well as a novel tool to perform parameter inference studies on both simulated and real GW data. Developments in this aspect of GW modelling are highly timely, considering the imminent release of the LVK fourth observation run catalogue, the upcoming upgrades to the LVK facilities and the recent adoption of the LISA mission.