Dynamical descalarization in binary black hole mergers

TL;DR

This paper explores how binary black hole mergers can lead to either the formation or loss of scalar hair through dynamical processes, expanding understanding beyond single black hole scenarios.

Contribution

First numerical relativity study of dynamical scalarization and descalarization in black hole binaries during mergers.

Findings

Black hole binaries can form scalarized remnants.

Binaries can shed scalar hair and descalarize.

Implications for gravitational wave observations.

Abstract

Scalar fields coupled to the Gauss-Bonnet invariant can undergo a tachyonic instability, leading to spontaneous scalarization of black holes. Studies of this effect have so far been restricted to single black hole spacetimes. We present the first results on dynamical scalarization in head-on collisions and quasicircular inspirals of black hole binaries with numerical relativity simulations. We show that black hole binaries can either form a scalarized remnant or dynamically descalarize by shedding off its initial scalar hair. The observational implications of these findings are discussed.