Galaxy Evolution in the Local Universe: Group Richness Effects on Mergers and Non-Mergers

TL;DR

This study investigates how group richness affects galaxy properties and their differences between mergers and non-mergers in the local Universe, revealing mass-dependent variations in star formation and stellar populations.

Contribution

It provides new insights into the influence of group richness on galaxy properties and their relationships with stellar mass, using SDSS data and Galaxy Zoo classifications.

Findings

Low-mass mergers have higher SFR and are bluer than non-mergers.

High-mass galaxies show weak property differences between mergers and non-mergers.

Group richness and stellar mass significantly influence galaxy property distributions.

Abstract

In this study, we use the luminous volume-limited samples obtained from the twelfth release of Sloan Digital Sky Survey data and mergers from Galaxy Zoo Project to investigate the influence of group richness in shaping galaxy properties' distributions and their relationships in the local Universe by comparison of mergers and non-mergers. The galaxies were restricted into mass-limited subsamples of low-mass, intermediate-mass and high-mass, assigned into groups from poor to rich group systems, where the distributions of star formation rate (SFR), specific SFR (SSFR), spectral index D$_n$ (4000) and $u-r$ colour properties between mergers and non-mergers for all subsamples and their relations with stellar mass of galaxies are compared. The study revealed a significant difference in the distributions between mergers' and non-mergers' properties for low-mass galaxies, while for high-mass galaxies the difference is very weak. For the low-mass sample, mergers possess higher SFR, SSFR than non-mergers when the group richness is kept constant, while for high-mass poor group galaxies have higher SFR, SSFR than rich group galaxies when merging status is kept constant. Mergers resemble young stellar populations and are bluer than non-mergers for low-mass, while for high-mass, mergers and non-mergers have comparable SFR, SSFR, D$_n$ (4000), and $u-r$ colour. The study concludes that group richness and stellar mass influence the mergers' and non-mergers' properties' distributions, and their relationships.