Black hole superradiance in dynamical spacetime

William E. East, Fethi M. Ramazanoǧlu, Frans Pretorius

Research output: Contribution to journalArticle

26 Scopus citations

Abstract

We study the superradiant scattering of gravitational waves by a nearly extremal black hole (dimensionless spin a=0.99) by numerically solving the full Einstein field equations, thus including backreaction effects. This allows us to study the dynamics of the black hole as it loses energy and angular momentum during the scattering process. To explore the nonlinear phase of the interaction, we consider gravitational wave packets with initial energies up to 10% of the mass of the black hole. We find that as the incident wave energy increases, the amplification of the scattered waves, as well as the energy extraction efficiency from the black hole, is reduced. During the interaction the apparent horizon geometry undergoes sizable nonaxisymmetric oscillations. The largest amplitude excitations occur when the peak frequency of the incident wave packet is above where superradiance occurs, but close to the dominant quasinormal mode frequency of the black hole.

Original languageEnglish (US)
Article number061503
JournalPhysical Review D - Particles, Fields, Gravitation and Cosmology
Volume89
Issue number6
DOIs
StatePublished - Mar 20 2014

All Science Journal Classification (ASJC) codes

  • Nuclear and High Energy Physics
  • Physics and Astronomy (miscellaneous)

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