Black hole horizons from the double copy

We describe a procedure for locating black hole horizons in 'Kerr-Schild' spacetimes in the double copy paradigm. Using only single- and zeroth-copy data on flat spacetime, our procedure predicts the existence of trapped surfaces in the double-copy gravitational solution. We show explicitly how this procedure locates the horizon of the Schwarzschild black hole and the general Myers-Perry black hole.