Physical drivers of quenching in massive centrals – an observational and simulated perspective

Understanding the physics behind galaxy quenching is one of the most important questions in the field of galaxy evolution. We investigate how quenching operates in local, massive, central galaxies by comparing the Universe observed by the Sloan Digital Sky Survey (SDSS) with cosmological simulations – EAGLE, Illustris and TNG. Our machine learning analysis reveals supermassive black hole (SMBH) mass as the most relevant parameter for determining whether a galaxy is star-forming or quenched. We also show that the observed correlations between quiescence and other galactic properties are of secondary importance and stem from their connection with the SMBH mass. We then infer molecular gas content from the reddening of SDSS spectra and compare it with simulations to understand the physical mechanism of SMBH feedback. Our results indicate that SMBH can successfully quench massive centrals by combining preventative heating feedback and turbulence injection into the interstellar medium.