Improved Binary Black Hole Initial Data

This thesis focuses on improving initial data for binary black hole simulations within numerical relativity. Currently, the most common approach involves conformally flat initial data, which successfully models the black holes but fails to capture the gravitational radiation. We reproduce previous work that attempted to add radiative content to initial data, applying it to an excision code where constraints are solved.

Using the XCTS formalism, we solve the constraint equations for binary black hole initial data with radiative content derived from a Post-Newtonian approximation. We evolve a system with equal mass and large separation, though computational limitations prevented evolution at smaller separations, where the radiation is relevant.

By adjusting the inner zone metric, it was possible to solve the constraints and evolve a system with smaller separation. We observed the expected gravitational radiation in early evolution. The findings suggest that initial data solutions for the constraint equations are sensitive to inner zone background data and boundary conditions, affecting evolution outcomes. The results also indicate a strong effect of resolution on the quality of the extracted gravitational wave forms.

In upcoming work, we will explore the effects of the initial data radiative content on the transition to evolution generated waves by running various tests with high resolution. The results of this work will provide a better understanding of the effects of initial data on the evolution of binary black hole systems and the quality of the extracted gravitational wave forms.