Kerr-Schild metrics revisited I. The ground state
arXiv:gr-qc/0203088 · doi:10.1063/1.530515
Abstract
The Kerr-Schild pencil of metrics $g_{ab}+\La l_al_b$ is investigated in the generic case when it maps an arbitrary vacuum space-time with metric to a vacuum space-time. The theorem is proved that this generic case, with the field shearing, does not contain the shear-free subclass as a smooth limit. It is shown that one of the Kóta-Perjés metrics is a solution in the shearing class.
16 pages