Binary black hole spacetimes in harmonic coordinates

Harmonic coordinates are often used in analytical relativity calculations targeted at binary black hole spacetimes, as they provide for the simplification of Einstein equations to a set of quasilinear wave equations. In this talk, I will discuss the existence and characteristics of simple harmonic coordinates in highly dynamical (numerical) spacetimes of merging black holes. I will also describe a method of tracking black hole trajectories in pure harmonic coordinates. This method has the potential to enable gauge-dependent comparisons of two-body kinematics between Numerical Relativity and post-Newtonian theory results, allowing for better calibration of general relativistic models for binary black hole dynamics.