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

• Main Authors: Schaefer, A., Croom, S., Scott, N., Brough, S., Allen, J., Bekki, K., Bland-Hawthorn, J., Bloom, J., Bryant, J., Cortese, L., Davies, L., Federrath, C., Fogarty, L., Green, A., Groves, B., Hopkins, A., Konstantopoulos, I., López-Sánchez, A., Lawrence, J., McElroy, R., Medling, A., Owers, M., Pracy, M., Richards, S., Robotham, A., van de Sande, J., Tonini, C., Yi, S.
• Format: Article in Journal/Newspaper
• Language: unknown
• Published: 2019
• Subjects: sami
• Online Access: http://hdl.handle.net/21.11116/0000-0005-CFDA-D

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 ̃eq 10^{14} M_☉) from the Galaxy And Mass Assembly Survey, we find signatures of environmental quenching in high-mass groups (M_{ G} > 10^{12.5} M_{☉}). 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 ∆ log ( sSFR/yr^{-1}) = 0.45 ± 0.07. This difference is seen at all galaxy stellar masses. In high-mass groups, star-forming galaxies more massive than M_{*} ̃ 10^{10} M_{☉} 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 M_{ G} = 10^{12.5} M_{☉}, 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.