Quenching of Massive Disk Galaxies in the IllustrisTNG Simulation

Abstract

A rare population of massive disk galaxies have been found to invade the red sequence dominated by early-type galaxies. These red/quenched massive disk galaxies have recently gained great interest into their formation and origins. The usually proposed quenching mechanisms, such as bar quenching and environment quenching, seem not suitable for those bulge-less quenched disks in low-density environment. In this paper, we use the TNG300 simulation to investigate the formation of massive quenched central disk galaxies. It is found that these galaxies contain less gas and harbor giant supermassive black holes(SMBHs) (above 10 8 M ) than their star forming counterparts. By tracing their formation history, we found that quenched disk galaxies formed early and preserved disk morphology for cosmological time scales. They have experienced less than one major merger on average and it is mainly mini-mergers (mass ratio <1/10) that contribute to the growth of their SMBHs. In the IllustrisTNG simulation the black hole feedback mode switches from thermal to kinetic feedback when the black hole mass is more massive than ∼ 10 8 M , which is more efficient to eject gas outside of the galaxy and to suppress further cooling of hot gaseous halo. We conclude that kinetic AGN feedback in massive red/quenched disk galaxy is the dominant quenching mechanism.

Revealing impacts of stellar mass and environment on galaxy quenching

“…Among the stellar mass driven quenching, the most studied mechanism is AGN feedback (Best et al 2005;Hopkins et al 2005;Kaviraj et al 2007;Diamond-Stanic et al 2012;Belli et al 2021), which is also studied in simulations (e.g. Dubois et al 2013;Beckmann et al 2017;Weinberger et al 2017;Piotrowska et al 2021;Shi et al 2022;Xu et al 2022). The quasar host AGNs show evidence of having strong outflows in observa-tion (Dai et al 2008;Tombesi et al 2010).…”