Numerical solutions to rotating black holes up to arbitrary spin in dynamical Chern-Simons gravity

We numerically solve for the metrics of axisymmetric black holes in dynamical Chern-Simons gravity using an effective field theory approach. We use an order-reduction scheme to express the field equations as a perturbation on a Kerr background solution. Further, we exploit the axial symmetry of the system to optimize the numerical scheme and study the solution using spectral methods in the Spectral Einstein Code (SpEC). The metric tensor solutions, which are valid for arbitrary spin for the black hole, have implications for observables like the black hole shadow or entropy.