The dominant role of dark matter halo in quenching central galaxies

Abstract

Understanding the quenching of star formation in central galaxies remains a core challenge in galaxy evolution. Two decades ago, the concept of halo quenching was introduced as a dominant mechanism, positing that massive central galaxy quenching is governed by the thermodynamics of gas predominantly influenced by dark matter halos. However, a vastly increasing body of observational evidence consistently indicates that quenching correlates predominantly with central properties like velocity dispersion, bulge mass, and black hole mass. When these properties are controlled, halo mass appears to show weak influence, supporting AGN feedback as the primary mechanism. A recurring key issue, however, is that these studies rely on halo masses derived via abundance matching (AM). Direct observational measurements from weak lensing, satellite kinematics, and galactic dynamics reveal that AM systematically overestimates halo masses of star-forming centrals while underestimating those of passive ones. To accurately assess the true role of halo mass. we re-estimated halo masses for SDSS groups; the resulting halo mass function and stellar-to-halo mass relations (SHMRs) for both populations match theoretical predictions and weak lensing measurements. Using these improved masses, we find direct observational evidence that halo mass is the dominant factor in quenching central galaxies, with a clear threshold at $M_{h}\sim 10^{12.1}M_\odot; $. By applying a simple correction to AM data using weak lensing-derived SHMRs, we demonstrate that previous claims regarding the dominance of central properties stem primarily from systematic biases in AM halo masses. Our results suggest that the significance of AGN feedback is primarily manifested in halos above this mass threshold, in galaxies already primed for quenching. In other words, AGN feedback appears to become effective in halos above this mass threshold.