A feedback process in galaxy clusters where energy from a central black hole balances the cooling of the surrounding gas.In galaxy clusters, the hot gas between galaxies should cool over time, condensing and forming new stars. But observations show that this cooling is largely prevented: the gas stays hot, and star formation is suppressed. The self-regulating mechanism is the process that explains this balance. It involves a supermassive black hole at the cluster's center, which acts as a thermostat for the entire cluster.
The concept emerged in the late 1990s and early 2000s from X-ray observations of galaxy clusters, which showed that cooling flows were much weaker than expected. It was developed through theoretical work and simulations by astrophysicists studying active galactic nuclei feedback.
As hot gas cools, it flows inward toward the central black hole, feeding it. This accretion of matter releases enormous energy in the form of jets and radiation, which heats the surrounding gas. The heated gas expands and stops flowing inward, cutting off the black hole's fuel supply. This negative feedback loop keeps the gas temperature and the black hole's activity in a stable equilibrium.
This mechanism is used in cosmological simulations to model galaxy formation and evolution, helping predict how galaxies and clusters grow over cosmic time.
The energy output from a single supermassive black hole can be so large that it heats gas across a region millions of light-years wide, affecting the entire cluster.










