Initial data for extreme binary black holes with the NRPyElliptic solver*

Numerical relativity simulations of binary black holes (BBHs) form the foundation for gravitational wave (GW) data analysis. A great majority of these simulations cover zero- to moderate-spin scenarios. Modeling high to near-extremal spins is essential to the field of GW science, but is far more difficult. One challenge stems from the requirement that generating simulation initial data (ID) involves solving the (elliptic PDE) ADM Hamiltonian and momentum constraint equations for two superposed, conformally curved, boosted single-BH solutions. NRPyElliptic solves these constraint equations via a fast hyperbolic relaxation method. In its first version, it supported conformally flat, binary puncture ID. I will report on our new implementation of conformally curved BBH ID relaxations, as well as on infrastructure updates that make NRPyElliptic both faster and more flexible.