Regensburg 1998 – scientific programme

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GR: Gravitation und Relativitätstheorie

GR 4: Gravitationswellen, Lichtausbreitung im Gravitationsfeld

GR 4.2: Invited Talk

Thursday, March 26, 1998, 10:15–11:00, H47

Classification of stable caustics — •Volker Perlick¹, Wolfgang Hasse¹, and Marcus Kriele² — ¹TU Berlin, Inst.Theor.Phys., 10623 Berlin — ²TU Berlin, Fachbereich Mathematik, 10623 Berlin

In a spacetime (i.e., in a 4-dimensional Lorentzian manifold) a family of light rays issuing orthogonally from a spacelike 2-surface makes up a so-called wavefront. The caustic of a wavefront is the set of all points where the wavefront fails to be an immersed 3-dimensional manifold. In this talk a reduction formalism to locally visualize caustics in 3-dimensional space, rather than in 4-dimensional spacetime, will be discussed, and Arnold’s theory of Lagrangian singularities will be applied to give a local classification of stable caustics. Moreover, the relevance of these results in view of gravitational lensing will be discussed.