Galaxy And Mass Assembly (GAMA): Trends in galaxy colours, morphology, and stellar populations with large scale structure, group, and pair environments

TL;DR

This study investigates how galaxy properties like colour, morphology, and stellar populations vary across different large-scale environments, finding stellar mass to be the primary predictor of these properties rather than environment.

Contribution

It introduces a mass-matched galaxy sample to disentangle the effects of stellar mass from environment on galaxy properties, revealing mass as the dominant factor.

Findings

Galaxy properties are similar across different large-scale environments when controlling for stellar mass.

Color correlates strongly with halo mass, but morphology and luminosity do not.

Environmental effects are less significant than stellar mass in determining galaxy characteristics.

Abstract

We explore trends in galaxy properties with Mpc-scale structures using catalogues of environment and large scale structure from the Galaxy And Mass Assembly (GAMA) survey. Existing GAMA catalogues of large scale structure, group and pair membership allow us to construct galaxy stellar mass functions for different environmental types. To avoid simply extracting the known underlying correlations between galaxy properties and stellar mass, we create a mass matched sample of galaxies with stellar masses between $9.5 \leq \log{M_*/h^{-2} M_{\odot}} \leq 11$ for each environmental population. Using these samples, we show that mass normalised galaxies in different large scale environments have similar energy outputs, $u-r$ colours, luminosities, and morphologies. Extending our analysis to group and pair environments, we show galaxies that are not in groups or pairs exhibit similar characteristics to each other regardless of broader environment. For our mass controlled sample, we fail to see a strong dependence of S\'{e}rsic index or galaxy luminosity on halo mass, but do find that it correlates very strongly with colour. Repeating our analysis for galaxies that have not been mass controlled introduces and amplifies trends in the properties of galaxies in pairs, groups, and large scale structure, indicating that stellar mass is the most important predictor of the galaxy properties we examine, as opposed to environmental classifications.