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

• Published in: Monthly Notices of the Royal Astronomical Society
• Main Authors: Schaefer, AL, Croom, SM, Scott, N, Brough, S, Allen, JT, Bekki, K, Bland-Hawthorn, J, Bloom, JV, Bryant, JJ, Cortese, L, Davies, LJM, Federrath, C, Fogarty, LMR, Green, AW, Groves, B, Hopkins, AM, Konstantopoulos, IS, López-Sánchez, AR, Lawrence, JS, McElroy, RE, Medling, AM, Owers, MS, Pracy, MB, Richards, SN, Robotham, ASG, Van De Sande, J, Tonini, C, Yi, SK
• Format: Article in Journal/Newspaper
• Language: unknown
• Published: Oxford University Press (OUP) 2019
• Subjects: anzsrc-for: 0201 Astronomical and Space Sciences; sami
• Online Access: http://hdl.handle.net/1959.4/unsworks_57967; https://doi.org/10.1093/mnras/sty3258

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 ≃ 1014M⊙) from the Galaxy And Mass Assembly Survey, we find signatures of environmental quenching in high-mass groups (MG ≥ 1012.5M⊙). The mean integrated specific star formation rate (sSFR) of star-forming galaxies in high-mass groups is lower than for galaxies in low-mass groups or those that are ungrouped, with Δlog(sSFR/yr-1) = 0.45 ± 0.07. This difference is seen at all galaxy stellar masses. In high-mass groups, starforming galaxies more massive than M∗ ∼ 1010M⊙ have centrally concentrated star formation. These galaxies also lie below the star formation main sequence, which suggests 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 MG = 1012.5M⊙, we do not observe these trends. In this regime, we find a modest correlation between centrally concentrated star formation and an enhancement in the total star formation rate, consistent with triggered star formation in these galaxies.