Spacetime Ehlers group: transformation law for the Weyl tensor
Abstract
The spacetime Ehlers group, which is a symmetry of the Einstein vacuum field equations for strictly stationary spacetimes, is defined and analysed in a purely spacetime context (without invoking the projection formalism). In this setting, the Ehlers group finds its natural description within an infinitedimensional group of transformations that maps Lorentz metrics into Lorentz metrics and which may be of independent interest. The Ehlers group is shown to be well defined independently of the causal character of the Killing vector (which may become null on arbitrary regions). We analyse which global conditions are required on the spacetime for the existence of the Ehlers group. The transformation law for the Weyl tensor under Ehlers transformations is obtained explicitly. This allows us to study where, and under what circumstances, curvature singularities in the transformed spacetime will arise. The results of the paper are applied to obtain a local characterization of the KerrNUT metric.
 Publication:

Classical and Quantum Gravity
 Pub Date:
 February 2001
 DOI:
 10.1088/02649381/18/4/311
 arXiv:
 arXiv:grqc/0101020
 Bibcode:
 2001CQGra..18..719M
 Keywords:

 General Relativity and Quantum Cosmology
 EPrint:
 LaTeX, 25 pages, no figures, uses Amstex. Accepted for publication in Classical and Quantum Gravity