2014/07/31 by Luciano Rezzolla, Alexander Zhidenko · 1 citation
Physics and Astronomy · #gr-qc
paper · pdf · doi:10.1103/physrevd.90.084009
published as Phys. Rev. D 90, 084009 (2014) · Appendix added for a more detailed comparison; matches version in PRD
arxiv created 2014/09/25 · arxiv updated 2014/10/09
We propose a new parametric framework to describe in generic metric theories of gravity the spacetime of spherically symmetric and slowly rotating black holes. In contrast to similar approaches proposed so far, we do not use a Taylor expansion in powers of M/r, where M and r are the mass of the black hole and a generic radial coordinate, respectively. Rather, we use a continued-fraction expansion in terms of a compactified radial coordinate. This choice leads to superior convergence properties and allows us to approximate a number of known metric theories with a much smaller set of coefficients. The measure of these coefficients via observations of near-horizon processes can be used to effectively constrain and compare arbitrary metric theories of gravity. Although our attention is here focussed on spherically symmetric black holes, we also discuss how our approach could be extended to rotating black holes.