title: Geometry and regularity of moving punctures.
abstract: Significant advances in numerical simulations of black-hole binaries have recently been achieved using the puncture method. We examine how and why this method works by evolving a single black hole. The coordinate singularity and hence the geometry at the puncture are found to change during evolution, from representing an asymptotically flat end to being a cylinder. We construct an analytic solution for the stationary state of a black hole in spherical symmetry that matches the numerical result and demonstrates that the evolution is not dominated by artefacts at the puncture but indeed finds the analytical result.
authors.affiliation: Theoretical Physics Institute, University of Jena, 07743 Jena, Germany.
authors.forename: Mark
authors.initials: M
authors.lastname: Hannam
authors.forename: Sascha
authors.initials: S
authors.lastname: Husa
authors.forename: Denis
authors.initials: D
authors.lastname: Pollney
authors.forename: Bernd
authors.initials: B
authors.lastname: Brügmann
authors.forename: Niall O
authors.initials: NO
authors.lastname: Murchadha