Supermassive black holes at the centers of galaxies play a critical role in regulating galaxy evolution, particularly star formation.

Nearly every massive galaxy harbors a supermassive black hole (SMBH) at its core, with masses millions to billions of times that of the Sun. Observations indicate a tight correlation between the mass of these SMBHs and the properties of their host galaxies' bulges. While these black holes are tiny compared to the galaxy, the energy released during accretion onto the SMBH (known as active galactic nucleus, or AGN, feedback) can have a profound impact. It can heat and expel gas from the galaxy, preventing it from cooling and forming new stars, thereby quenching star formation. This feedback mechanism is considered essential for explaining why star formation ceases in massive galaxies and for shaping the observed galaxy luminosity function.