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

A. L. Schaefer*, S. M. Croom, N. Scott, S. Brough, J. T. Allen, K. Bekki, J. Bland-Hawthorn, J. V. Bloom, J. J. Bryant, L. Cortese, L. J. M. Davies, C. Federrath, L. M. R. Fogarty, A. W. Green, B. Groves, A. M. Hopkins, I. S. Konstantopoulos, A. R. López-Sánchez, J. S. Lawrence, R. E. McElroyA. M. Medling, M. S. Owers, M. B. Pracy, S. N. Richards, A. S. G. Robotham, J. van de Sande, C. Tonini, S. K. Yi

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

27 Citations (Scopus)


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.

Original languageEnglish
Pages (from-to)2851-2870
Number of pages20
JournalMonthly Notices of the Royal Astronomical Society
Issue number3
Publication statusPublished - 1 Mar 2019


  • Galaxies: evolution
  • Galaxies: groups: general
  • Galaxies: interactions
  • Galaxies: star formation
  • Galaxies: structure


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