München 2019 – wissenschaftliches Programm
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GR: Fachverband Gravitation und Relativitätstheorie
GR 7: Modified Gravity and Applications
GR 7.5: Vortrag
Mittwoch, 20. März 2019, 12:00–12:15, HS 5
Black Hole Superradiance in Modified Gravity (MOG) — •Michael F. Wondrak1,2, Piero Nicolini1,2, and John W. Moffat3 — 1Frankfurt Institute for Advanced Studies (FIAS), Frankfurt am Main, Germany — 2Institut für Theoretische Physik, Johann Wolfgang Goethe-Universität Frankfurt, Frankfurt am Main, Germany — 3Perimeter Institute for Theoretical Physics, Waterloo, ON, Canada
When bosonic fields scatter off a black hole, the reflected radiation can gain a larger field amplitude than the incident one. This phenomenon, called superradiance, is typically sourced by the black hole electric charge or its angular momentum.
In this talk, we investigate superradiant scattering by black holes in Moffat's modified gravity (MOG). This theory replaces the need for dark matter in favor of an additional gravitational interaction. By comparison with Einstein's general relativity (GR), we find that the properties of superradiance crucially depend on the MOG parameter space: Even for small deviations from GR, there is a distinct reduction in the critical amplification frequency and in the overall brightness. Astronomical observation of superradiant scattering thus could provide an accurate test of MOG.