Speaker
Description
As galaxies merge, the eventual coalescence of their central supermassive black holes generates gravitational waves. It will take decades before specialized observatories capable of detecting gravitational radiation become operational, thereby providing the tools to study the coalescence of supermassive black holes. Yet, it is currently possible to detect the effects of the coalescence imprinted on the properties of the final merged supermassive black hole, offering an indirect means of probing its origin in a multi-messenger approach. In this talk, I will trace the imprinted properties of a supermassive black hole back to the coalescence of a pair of these objects. Ultra-deep high-energy observations provide evidence that the recoil of the final merged supermassive black hole is driven by gravitational waves generated during this event, and that the its spin is consistent with theoretical prediction from supermassive black hole mergers.