They suggest that as gravitational waves continued to amplify and collide, this led to conditions where small disturbances in space (scalar perturbations) become much larger than gravitational waves.

Recent theoretical and observational advances have revitalised the study of black holes endowed with scalar fields. Traditionally, the no‐hair theorem suggested that black holes could be fully ...

They suggest that as gravitational waves continued to amplify and collide, this led to conditions where small disturbances in space (scalar perturbations) become much larger than gravitational waves.