Ringing black holes are superradiant: The case of ultralight scalar fields

Superradiance has been studied quite extensively in the context of static (charged) and rotating black hole spacetime. In this paper, we report for the first time that for a minimally coupled scalar field, the absorption cross-section of a Schwarzschild black hole in its ring down phase can be superradiant. Our present result opens up an intriguing possibility of observing the black hole merging phenomena through other fundamental fields.