Quenched fractions in the IllustrisTNG simulations: the roles of AGN feedback, environment, and pre-processing

Martina Donnari; Annalisa Pillepich; Gandhali D. Joshi; Dylan Nelson; Shy Genel; Federico Marinacci; Vicente Rodriguez-Gomez; Ruediger Pakmor; Paul Torrey; Mark Vogelsberger; Lars Hernquist

doi:10.1093/mnras/staa3006

paper

Quenched fractions in the IllustrisTNG simulations: the roles of AGN feedback, environment, and pre-processing

arXiv:2008.00005 · doi:10.1093/mnras/staa3006

Abstract

We use the IllustrisTNG simulations to show how the fractions of quenched galaxies vary across different environments and cosmic time, and to quantify the role AGN feedback and preprocessing play in quenching group and cluster satellites. At $z = 0$ , we select galaxies with $M_{*} = 1 0^{9 - 12} M_{⊙}$ residing within ( $\leq R_{200 c}$ ) groups and clusters of total host mass $M_{200 c} = 1 0^{13 - 15.2} M_{⊙}$ . TNG predicts a quenched fraction of $\sim 70 - 90%$ (on average) for centrals and satellites $≳ 1 0^{10.5} M_{⊙}$ , regardless of host mass, cosmic time ( $0 \leq z \leq 0.5$ ), clustercentric distance and time since infall in the $z = 0$ host. Low-mass centrals ( $≲ 1 0^{10} M_{⊙}$ ), instead, are rarely quenched unless they become members of groups ( $1 0^{13 - 14} M_{⊙}$ ) or clusters ( $\geq 1 0^{14} M_{⊙}$ ), where the quenched fraction rises to $\sim 80%$ . The fraction of low-mass passive galaxies is higher closer to the host center and for more massive hosts. The population of low-mass satellites accreted $≳$ 4-6 Gyr ago in massive hosts is almost entirely passive, thus suggesting an upper limit for the time needed for environmental quenching to occur. In fact, $\sim 30%$ of group and cluster satellites that are quenched at $z = 0$ were already quenched before falling into their current host, and the bulk of them quenched as early as 4 to 10 billion years ago. For low-mass galaxies ( $≲ 1 0^{10 - 10.5} M_{⊙}$ ), this is due to preprocessing, whereby current satellites may have been members of other hosts, and hence have undergone environmental processes, before falling into their final host, this mechanism being more common and more effective for the purposes of quenching for satellites found today in more massive hosts. On the other hand, massive galaxies quench on their own and because of AGN feedback, regardless of whether they are centrals or satellites.

21 Pages, 11 figures, 2 tables, 1 appendix, published in MNRAS

Quenched fractions in the IllustrisTNG simulations: the roles of AGN feedback, environment, and pre-processing

Abstract

References in corpus (34)

Cited by in corpus (116)