The Shear at the Common Dynamical Horizon in Binary Black Hole Mergers and its Imprint in their Gravitational Radiation

This paper studies the shear of the outer common dynamical horizon in BBH mergers and how it tracks the waveform seen at future null infinity. By introducing an area-based time parametrization on the horizon, the authors find a strong correlation between horizon shear features and the gravitational strain, across several mergers. The framework provides a concrete map between strong-field horizon dynamics and asymptotic radiation, and is used to interpret prominent features of loud events.

Phys. Rev. D 111, 084070 (2025)