Black holes in alternative gravity theories

In our quest towards a theory of gravity beyond General Relativity black holes with their strong gravitational fields represent an important testing ground. Among the numerous alternative theories of gravity much work in recent years has focused on a set of scalar-tensor theories, where the scalar field couples to higher curvature terms. The properties of the resulting black holes in such theories may differ distictly from those of the Schwarzschild and Kerr black holes as, for instance, revealed by their shadows or their gravitational wave spectra.