Spacetime near isolated and dynamical trapping horizons

Understand

We study the near-horizon spacetime for isolated and dynamical trapping horizons (equivalently marginally outer trapped tubes).

• The metric is expanded relative to an ingoing Gaussian null coordinate and the terms of that expansion are explicitly calculated to second order.
• For the spacelike case, knowledge of the intrinsic and extrinsic geometry of the (dynamical) horizon is sufficient to determine the near-horizon spacetime, while for the null case (an isolated horizon) more information is needed.
• In both cases spacetime is allowed to be of arbitrary dimension and the formalism accomodates both general relativity as well as more general field equations.