Heidelberg 2022 – wissenschaftliches Programm

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GR: Fachverband Gravitation und Relativitätstheorie

GR 1: Black Holes

GR 1.1: Vortrag

Montag, 21. März 2022, 09:00–09:20, GR-H2

Photon spheres and shadows of time-dependent black holes — Jay Solanki¹ and •Volker Perlick² — ¹Sardar Vallabhbhai National Institute of Technology, Surat, 395007 Gujarat, India — ²ZARM, University of Bremen, 28359 Bremen, Germany

The Vaidya spacetimes are a class of time-dependent and spherically symmetric solutions to Einstein's field equation with a null dust as the source. They describe the gravitational field around a spherically symmetric body that either gains mass by absorbing the null dust or loses mass by emitting it. Here we consider a subclass of the Vaidya spacetimes where the source is a black hole and the metric is conformally static. We demonstrate that there is an unstable photon sphere and we calculate the shadow of such black holes, first as seen by conformally static observers and then as seen by moving observers. The considered spacetimes may be viewed as simple models of black holes that are either accreting or (Hawking) radiating.