Examining the Kerr metric through wave fronts of null geodesics

• DOI: 10.1007/s10714-019-2518-1
• Publication Date: 2019-02-20T08:16:08Z
• Authors: Thomas P. Kling; Eric Grotzke; Kevin Roebuck; Harry Waite
• Keywords: Caustic (mathematics); Null (SQL)

We examine the singularities of the wave fronts of null geodesics from point sources in the Kerr Metric. We find that the wave fronts develop a tube like structure that collapses non-symmetrically, leading to cusp features in the wave front singularities. As the wave front advances, the cusps trace out an astroidal shaped caustic tube, which had been discovered previously using lens mapping and geodesic deviation methods. Thus, the wave front approach in this study helps to complete a picture of caustics and gravitational lensing in the Kerr geometry.<br/>This is a post-peer-review, pre-copyedit version of an article published in General Relativity and Gravitation. The final authenticated version is available online at: https://doi.org/10.1007/s10714-019-2518-1<br/>