The SAMI Galaxy Survey: Observing the environmental quenching of star formation in GAMA groups

• Published in: arXiv.org
• Main Authors: Schaefer, A L, Croom, S M, Scott, N, Brough, S, Allen, J T, Bekki, K, Bland-Hawthorn, J, Bloom, J V, Bryant, J J, Cortese, L, Davies, L J M, Federrath, C, Fogarty, L M R, Green, A W, Groves, B, Hopkins, A M, Konstantopoulos, I S, López-Sánchez, A R, Lawrence, J S, McElroy, R E, Medling, A M, Owers, M S, Pracy, M B, Richards, S N, Robotham, A S G, van de Sande, J, Tonini, C, Yi, S K
• Format: Paper
• Language: English
• Published: Ithaca Cornell University Library, arXiv.org 28.11.2018
• Subjects: Galactic evolution; Galaxies; Galaxy distribution; Local group (astronomy); Quenching; Radial distribution; Star & galaxy formation; Star formation rate; Stars & galaxies
• ISSN: 2331-8422

We explore the radial distribution of star formation in galaxies in the SAMI Galaxy Survey as a function of their local group environment. Using a sample of galaxies in groups (with halo masses less than \( \simeq 10^{14} \, \mathrm{M_{\odot}}\)) from the Galaxy And Mass Assembly Survey, we find signatures of environmental quenching in high-mass groups (\(M_{G} > 10^{12.5} \, \mathrm{M_{\odot}}\)). The mean integrated specific star formation rate of star-forming galaxies in high-mass groups is lower than for galaxies in low-mass groups or that are ungrouped, with \(\Delta \log(sSFR/\mathrm{yr^{-1}}) = 0.45 \pm 0.07\). This difference is seen at all galaxy stellar masses. In high-mass groups, star-forming galaxies more massive than \(M_{*} \sim 10^{10} \, \mathrm{M_{\odot}}\) have centrally-concentrated star formation. These galaxies also lie below the star-formation main sequence, suggesting they may be undergoing outside-in quenching. Lower mass galaxies in high-mass groups do not show evidence of concentrated star formation. In groups less massive than \(M_{G} = 10^{12.5} \, \mathrm{M_{\odot}}\) we do not observe these trends. In this regime we find a modest correlation between centrally-concentrated star formation and an enhancement in total star formation rate, consistent with triggered star formation in these galaxies.