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, 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, Andrew M. (R20610), 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: Article in Journal/Newspaper
• Language: English
• Published: U.K., Oxford University Press 2019
• Subjects: XXXXXX - Unknown; sami
• Online Access: https://doi.org/10.1093/mnras/sty3258; https://hdl.handle.net/1959.7/uws:66836

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.