## Kerr Spherical Photon Orbits

Interactive tool for visualizing spherical/circular photon orbits in Kerr

## Notes: Generalized harmonic form of Einstein’s equations from a gauge-fixed action

The generalized harmonic formulation can be derived by adding a gauge-fixing term to the Einstein-Hilbert action

## Poincaré section clicker for the double pendulum

Interactive toy for understanding Poincaré sections and chaos

## Location of the last stable orbit in Kerr spacetime

The dividing line between bound and plunging orbits is an algebraic variety

## Numerical relativity simulation of GW150914 beyond general relativity

The first astrophysically-relevant numerical simulation of merging black holes in a higher-curvature theory beyond GR.

## qnm: A Python package for calculating Kerr quasinormal modes, separation constants, and spherical-spheroidal mixing coefficients

qnm is an open-source Python package for computing the Kerr quasinormal mode frequencies, angular separation constants, and spherical-spheroidal mixing coeff...