Black hole hair formation in shift-symmetric generalised scalar-tensor gravity

Robert Benkel, Thomas P. Sotiriou, Helvi Witek

Research output: Contribution to journalArticlepeer-review


A linear coupling between a scalar field and the Gauss-Bonnet invariant is the only known interaction term between a scalar and the metric that: respects shift symmetry; does not lead to higher order equations; inevitably introduces black hole hair in asymptotically flat, 4-dimensional spacetimes. Here we focus on the simplest theory that includes such a term and we explore the dynamical formation of scalar hair. In particular, we work in the decoupling limit that neglects the backreaction of the scalar onto the metric and evolve the scalar configuration numerically in the background of a Schwarzschild black hole and a collapsing dust star described by the Oppenheimer-Snyder solution. For all types of initial data that we consider, the scalar relaxes at late times to the known, static, analytic configuration that is associated with a hairy, spherically symmetric black hole. This suggests that the corresponding black hole solutions are indeed endpoints of collapse.

Original languageEnglish (US)
Article number064001
JournalClassical and Quantum Gravity
Issue number6
StatePublished - Feb 20 2017
Externally publishedYes


  • alternative theories of gravity
  • black hole hair, numerics
  • black holes

ASJC Scopus subject areas

  • Physics and Astronomy (miscellaneous)


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