Berlin 2014 – scientific programme

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GR: Fachverband Gravitation und Relativitätstheorie

GR 17: Black Holes II

GR 17.2: Talk

Wednesday, March 19, 2014, 16:50–17:10, SPA SR220

Shadows and Photon Regions of Black Holes — •Arne Grenzebach, Claus Lämmerzahl, and Volker Perlick — ZARM, Universität Bremen, 28359 Bremen

I my talk I start with a short general definition of the concept of the shadow of black holes and describe how the shadow of a Kerr-Newman-NUT black hole with a cosmological constant can be determined. Here, the crucial point is the existence of (unstable) spherical light rays in a region K which determine the boundary of the shadow. This region K shrinks to the well known photon sphere in the Reissner-Nordström case. After transformation to celestial coordinates on the observer’s sky, the shadow can be viewed via stereographic projection.