Spin-induced dynamical scalarization, descalarization, and stealthness in scalar-Gauss-Bonnet gravity during a black hole coalescence

Particular couplings between a scalar field and the Gauss-Bonnet invariant lead to spontaneous scalarization of black holes. Here we continue our work on simulating this phenomenon in context binary hole systems. We consider negative coupling for which black-hole spin plays major role process. find two main phenomena: (i) dynamical descalarization, initially scalarized holes form an unscalarized remnant, (ii) scalarization, whereby late merger can cause hair grow. An important consequence latter case is that modifications gravitational waveform due may only occur post-merger, as its presence hidden during entirety inspiral. However, with sufficiently strong coupling, before remnant has even formed. close discussion observational implications gravitational-wave tests general relativity.