Galaxy And Mass Assembly (GAMA): Deconstructing the galaxy stellar mass function by star formation and environment

TL;DR

This study uses GAMA data to analyze how galaxy stellar mass functions vary with galaxy type, environment, and halo mass, revealing detailed differences in galaxy populations and their dependence on environment and mass.

Contribution

It provides a detailed decomposition of the galaxy stellar mass function by galaxy type and environment, highlighting the roles of centrals, satellites, and halo mass in galaxy evolution.

Findings

Passive and star-forming GSMFs are well described by Schechter functions.

Star-forming galaxies dominate low-mass end; passive galaxies dominate higher masses.

Environmental effects influence the abundance of low-mass galaxies.

Abstract

Using the equatorial Galaxy and Mass Assembly (GAMA) dataset, we investigate how the low-redshift galaxy stellar mass function (GSMF) varies across different galaxy populations and as a function of halo mass. We find that: (i) The GSMF of passive and star-forming galaxies are well described by a double and a single Schechter function, respectively, although the inclusion of a second component for the star-forming population yields a more accurate description. Furthermore, star-forming galaxies dominate the low-mass end of the total GSMF, whereas passive galaxies mainly shape the intermediate-to-high-mass regime. (ii) The GSMF of central galaxies dominates the high-mass end, whereas satellites and ungrouped galaxies shape the intermediate-to-low-mass regime. Additionally, we find a relative increase in the abundance of low-mass galaxies moving from dense group environments to isolated systems. (iii) More massive halos host more massive galaxies, have a higher fraction of passive systems, and show a steeper decline in the number of intermediate-mass galaxies. Finally, our results reveal larger differences between passive and star-forming GSMFs than predicted by a phenomenological quenching model, but generally confirm the environmental quenching trends for centrals and satellites reported in other works.