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