A note on degeneracy, marginal stability and extremality of black hole horizons

Abstract

Given a stationary axisymmetric black hole horizon admitting a section characterised as a strictly future stable marginally outer trapped surface, we extend the equivalence between the notions of horizon degeneracy and marginal stability to the fulfillment, under the dominant energy condition, of the A=8π|J| geometric relation between the area $A$ and the angular momentum J of a horizon section.

6 pages, no figures, updated to match published version

References in corpus (2)

• Isolated, slowly evolving, and dynamical trapping horizons: geometry and mechanics from surface deformations
• Extremality conditions for isolated and dynamical horizons