Evolution of star-forming dwarf galaxies in different environments

Abstract

The ubiquity of star-forming dwarf galaxies (SFDG) in the local Universe allows us to trace their evolution in all type of environments, from voids to rich clusters. SFDGs in low-density regions are still assembling their mass, they often show peculiar gas morphology and kinematics, likely associated to external gas accretion or galaxy interactions, and they can experience strong bursts of star formation. The most metal-poor SFDGs are found in the field and they are unique laboratories to investigate the star formation process in the low-metallicity regime, at conditions similar to their high-redshift analogues. On the other hand, SFDGs in intermediate-and high-density environments provide a key to understand the processes that remove their interstellar medium (ISM) and suppress star formation, leading to the different types of gas-poor early-type dwarfs. We review the most recent results on the properties of SFDGs at low and high galaxy densities focusing in particular on the impact of a cluster environment on their ISM components (dust, molecular, atomic and ionised gas). We analyse the population of SFDGs in the nearest rich clusters: Virgo, which is still in the process of assembly, and Fornax, which is more dynamically evolved, more compact and denser. We discuss how the different evolutionary stage of the two structures affects the properties of SFDGs.

Evolution of dwarf galaxy observable parameters

“…they predict much lower stellar masses at a given halo mass. This difference is also expected, since Garrison-Kimmel et al (2017) investigated satellite galaxies in the Local Group, which are presumably significantly affected by tidal stripping and other environmental quenching effects (Geha et al 2012;Grossi 2019). In the bottom panel, the cyan line shows the relation derived in Tremonti et al (2004) for a large sample of star-forming galaxies, while the magenta line shows the relation from Lee et al (2006), derived for a small sample of nearby dwarf irregulars.…”

A tale of two tails: insights from simulations into the formation of the peculiar dwarf galaxy NGC 1427A

“…The evolution of galaxies in dense environments has been shown to be markedly different from that of more isolated galaxies, with mass being a prominent factor in determining how profoundly environmental influences affect a galaxy (Boselli & Gavazzi 2006;Grossi 2018). The well-known morphology-density relation, according to which early-type galaxies are mostly found in high-density environments (Dressler 1980;Dressler et al 1997), is especially pronounced for low-mass systems, such as dwarf galaxies (McConnachie 2012).…”

Numerical simulations of dwarf galaxies in the Fornax Cluster

“…The evolution of galaxies in dense environments has been shown to be markedly different from that of more isolated galaxies, with mass being a prominent factor in determining how profoundly environmental influences affect a galaxy (Boselli & Gavazzi, 2006;Grossi, 2018). The wellknown morphology-density relation, according to which early-type galaxies are mostly found in high-density environments (Dressler, 1980;Dressler et al, 1997), is especially pronounced for low-mass systems, such as dwarf galaxies (McConnachie, 2012).…”