Cold Gas in Massive Galaxies as a Critical Test of Black Hole Feedback Models

Black hole feedback has been widely implemented as the key recipe to quench star formation in massive galaxies modern semi-analytic models and hydrodynamical simulations. As theoretical details surrounding accretion of black holes continue be refined, various have across simulations, with notable differences their outcomes. Yet, most these simulations successfully reproduced some observations, such stellar mass function rate density local Universe. We use recent observation on change neutral hydrogen gas (including both ${\rm H_2}$ HI}$) central disc a critical constraint several find that predictions IllustrisTNG agree observations much better than other tested this work. This favors IllustrisTNG's treatment active galactic nuclei - where kinetic winds are driven by at low rates more plausible amongst those we test. In turn, also indirectly supports idea galaxy population Universe was likely quenched AGN feedback.