Articulo
Unstable fields in Kerr spacetimes
Registro en:
issn:0264-9381
issn:1361-6382
Autor
Dotti, Gustavo
Gleiser, Reinaldo J.
Ranea Sandoval, Ignacio Francisco
Institución
Resumen
We show that both the interior region r < M − √M² − a² of a Kerr black hole and the a² > M² Kerr naked singularity admit unstable solutions of the Teukolsky equation for any value of the spin weight. For every harmonic number, there is at least one axially symmetric mode that grows exponentially in time and decays properly in the radial directions. These can be used as Debye potentials to generate solutions for the scalar, Weyl spinor, Maxwell and linearized gravity field equations on these backgrounds, satisfying appropriate spatial boundary conditions and growing exponentially in time, as shown in detail for the Maxwell case. It is suggested that the existence of the unstable modes is related to the so-called time machine region, where the axial Killing vector field is timelike, and the Teukolsky equation, restricted to axially symmetric fields, changes its character from hyperbolic to elliptic. Facultad de Ciencias Astronómicas y Geofísicas