Kerr-Schild Ansatz Revised
Andrea Geralico
(ICRA, University of Rome "Sapienza", Italy)
Coauthor(s): D. Bini, Roy P. Kerr
Download presentation
The Kerr-Schild ansatz is revised by treating Kerr-Schild metrics as "exact linear perturbations" of Minkowski space, being expressed as a linear superposition of the flat spacetime metric and a squared null vector field multiplied by some scalar function. Based just on this linearity property an alternative derivation of the Kerr solution is presented by distinguish in the Einstein as well as energy momentum tensors the contributions of different orders, i. e. powers of the scalar function, then solving separately each individual set of field equations. The basic assumption in the original derivation of Kerr solution was that the null congruence is both geodesic and shearfree. This condition is relaxed in the present treatment, where the field equations are solved without any assumption. It turns out that the congruence must be anyway geodesic and shearfree as a consequence of third and second order equations.