Eur. Phys. J. C (2016) 76: 290
https://doi.org/10.1140/epjc/s10052-016-4137-2

Regular Article - Theoretical Physics

Note on a new parametrization for testing the Kerr metric

¹ Department of Physics, Center for Field Theory and Particle Physics, Fudan University, Shanghai, 200433, China
² Theoretical Astrophysics, Eberhard-Karls Universität Tübingen, 72076, Tübingen, Germany

^* e-mail: bambi@fudan.edu.cn

Received: 3 February 2016
Accepted: 10 May 2016
Published online: 23 May 2016

Abstract

We propose a new parametrization for testing the Kerr nature of astrophysical black hole candidates. The common approaches focus on the attempt to constrain possible deviations from the Kerr solution described by new terms in the metric. Here we adopt a different perspective. The mass and the spin of a black hole make the spacetime curved and we want to check whether they do it with the strength predicted by general relativity. As an example, we apply our parametrization to the black hole shadow, an observation that may be possible in a not too distant future.