Perturbations of Kerr's spacetime and cosmic censorship

GUSVATO DOTTI; REINALDO J. GLEISER; IGNACIO FRANCISCO RANEA SANDOVAL

Estocolmo

Congreso; Thirteenth Marcel Grossmann Meeting; 2012

Stockholm University

In this work we study linear fields on Kerr´s spacetime, both in the region behind the Cauchy horizon of a black hole, and in the a^2 > M^2 naked singularity. The main result is the proof of existence of a family of axially symmetric unstable (i.e exponentially growing in time) modes satisfying appropriate spatial boundary conditions for all relevant linear fields: gravitational perturbations, electromagnetic fields, Weyl spinors and massless scalar fields. We then argue that these spacetimes are lineary unstable, and use this as an argument that favours the cosmic censorship hypotesis. We also give details related to the field reconstruction for the case of the electromagnetic perturbation, and study the behaviour of the unstable fields near the ring singularity.