Speaker
Description
I will discuss properties of general stationary and axisymmetric spacetimes, with a particular focus on circularity - an accidental symmetry enjoyed by the Kerr metric, and therefore widely assumed when searching for rotating black hole solutions in alternative theories of gravity as well as when constructing models of Kerr mimickers. It can be shown the local existence of a Kerr-like gauge, specified by six free functions. Within this gauge the differential circularity conditions can be solved to translate them into algebraic relations among the metric components. This result opens the way to investigating the consequences of circularity breaking in a controlled manner. In particular, I will show two simple analytical examples of non-circular deformations of the Kerr spacetime and discuss their properties.
