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Black holes and binary mergers in scalar Gauss-Bonnet gravity: scalar field dynamics

Research output: Contribution to journalArticlepeer-review

Helvi Witek, Leonardo Gualtieri, Paolo Pani, Thomas P. Sotiriou

Original languageEnglish
Article number064035
JournalPhysical Review D (Particles, Fields, Gravitation and Cosmology)
Issue number6
Accepted/In press13 Feb 2019
Published15 Mar 2019

Bibliographical note

24 pages; 12 figures; Numerical code based on the Einstein Toolkit with new thorns available at v2: updated references and discussion


King's Authors


We study the nonlinear dynamics of black holes that carry scalar hair and binaries composed of such black holes. The scalar hair is due to a linear or exponential coupling between the scalar and the Gauss--Bonnet invariant. We work perturbatively in the coupling constant of that interaction but nonperturbatively in the fields. We first consider the dynamical formation of hair for isolated black holes of arbitrary spin and determine the final state. This also allows us to compute for the first time the scalar quasinormal modes of rotating black holes in the presence of this coupling. We then study the evolution of nonspinning black-hole binaries with various mass ratios and produce the first scalar waveform for a coalescence. An estimate of the energy loss in scalar radiation and the effect this has on orbital dynamics and the phase of the GWs (entering at quadratic order in the coupling) show that GW detections can set the most stringent constraint to date on theories that exhibit a coupling between a scalar field and the Gauss--Bonnet invariant.

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