Galaxy and mass assembly (GAMA): impact of the group environment on galaxy star formation

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≤z≤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 ≤(M200/M⊙)<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 ∼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.