The persistence of hair in binary mergers in Einstein–Maxwell–dilaton–axion gravity

We investigate black hole mergers within Einstein–Maxwell–Dilaton–Axion (EMDA) gravity. Using the numerical code Dendro-GR, we consider the nonlinear dynamical evolution of binary black hole inspirals to explore beyond-GR aspects of this theory. In particular, we examine the growth and stability of dilaton and axion hair on these black holes through merger and ringdown. We look for possible departures between GR and EMDA waveforms and their detectability. We also consider the stability of hairy black holes across this family of alternative theories.