An extraordinary recent development in astrophysics was the discovery of the fossil relationship between central black hole mass and the stellar mass of galactic bulges. The physical process underpinning this relationship has become known as feedback
. The Chandra X-ray Observatory was instrumental in realizing the physical basis for feedback, by demonstrating a tight coupling between the energy released by supermassive black holes and the gaseous structures surrounding them. This white paper discusses how a great leap forward in X-ray collecting area and spectral resolution will allow a qualitatively new way of studying how feedback from black holes influenced the growth of structure.
