Environmental quenching of low-mass field galaxies

Abstract

In the local Universe, there is a strong division in the star-forming properties of lowmass galaxies, with star formation largely ubiquitous amongst the field population while satellite systems are predominantly quenched. This dichotomy implies that environmental processes play the dominant role in suppressing star formation within this low-mass regime (M ∼ 10 5.5−8 M ). As shown by observations of the Local Volume, however, there is a non-negligible population of passive systems in the field, which challenges our understanding of quenching at low masses. By applying the satellite quenching models of Fillingham et al. (2015) to subhalo populations in the Exploring the Local Volume In Simulations (ELVIS) suite, we investigate the role of environmental processes in quenching star formation within the nearby field. Using model parameters that reproduce the satellite quenched fraction in the Local Group, we predict a quenched fraction -due solely to environmental effects -of ∼ 0.52 ± 0.26 within 1 < R/R vir < 2 of the Milky Way and M31. This is in good agreement with current observations of the Local Volume and suggests that the majority of the passive field systems observed at these distances are quenched via environmental mechanisms. Beyond 2 R vir , however, dwarf galaxy quenching becomes difficult to explain through an interaction with either the Milky Way or M31, such that more isolated, field dwarfs may be self-quenched as a result of star-formation feedback.

The star formation histories of dwarf galaxies in Local Group cosmological simulations

“…These trends in τ90 are consistent with previous studies on dwarf galaxy quiescence (e.g. Davies et al 2019;Fillingham et al 2016Fillingham et al , 2018Simpson et al 2018), which find similar dependence on mass and environment. These authors argue that low-mass satellites may have had their star formation extinguished by the effects of ram-pressure and tidal stripping during their orbital evolution within in their host halos.…”

Predicting fully self-consistent satellite richness, galaxy growth and starformation rates from the STastical sEmi-Empirical modeL steel.

“…• The second component used is the halo mass-dependant cutoff (Fillingham et al 2018), which envisions that satellite galaxies below a given stellar mass (dependant on host halo mass) are immediately quenched.…”

Neutral Hydrogen Observations of Low Surface Brightness Galaxies around M101 and NGC 5485

“…This raises the possibility that satellite gas stripping and star formation quenching proceed differently around halos of similar mass, providing an important new observational constraint on the underlying physics (e.g. Wetzel et al 2015;Fillingham et al 2018;Simpson et al 2018;Garrison-Kimmel et al 2019).…”