The SAMI Galaxy Survey: Spatial resolved star formation gradients in GAMA group galaxies.

Contributors: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. McElroy, A. M. Medling, M. S. Owers, M. B. Pracy, S. N. Richards, A. S. G. Robotham, J. van de Sande, C. Tonini, S. K. Yi 


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 of star-forming galaxies in high-mass groups is lower than for galaxies in low-mass groups or 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, star-forming galaxies more massive than M∗∼1010M⊙ 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 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 total star formation rate, consistent with triggered star formation in these galaxies.


Publication Date: 
January 2019
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