Galaxy And Mass Assembly (GAMA): impact of the group environment on galaxy star formation

TL;DR

This study investigates how the environment within galaxy groups influences star formation, revealing that infalling galaxies exhibit suppressed star formation compared to field galaxies, especially in low-mass halos.

Contribution

It provides new insights into the impact of group environments on galaxy evolution by analyzing the phase space distribution and star formation activity in low-mass galaxy groups.

Findings

Star-forming fraction higher in recently accreted regions

Passive galaxies dominate virialized regions

Star formation rate slightly declines towards group centers

Abstract

We explore how the group environment may affect the evolution of star-forming galaxies. We select 1197 Galaxy And Mass Assembly (GAMA) groups at $0.05\leq z \leq 0.2$ and analyze the projected phase space (PPS) diagram, i.e. the galaxy velocity as a function of projected group-centric radius, as a local environmental metric in the low-mass halo regime $10^{12}\leq (M_{200}/M_{\odot})< 10^{14}$. We study the properties of star-forming group galaxies, exploring the correlation of star formation rate (SFR) with radial distance and stellar mass. We find that the fraction of star-forming group members is higher in the PPS regions dominated by recently accreted galaxies, whereas passive galaxies dominate the virialized regions. We observe a small decline in specific SFR of star-forming galaxies towards the group center by a factor $\sim 1.2$ with respect to field galaxies. Similar to cluster studies, we conclude for low-mass halos that star-forming group galaxies represent an infalling population from the field to the halo and show suppressed star formation.