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.
Bibliographical noteFunding Information:
The SAMI Galaxy Survey is based on observations made at the Anglo-Australian Telescope. The Sydney-AAO Multi-object Integral field spectrograph (SAMI) was developed jointly by the University of Sydney and the Australian Astronomical Observatory. The SAMI input catalogue is based on data taken from the Sloan Digital Sky Survey, the Galaxy And Mass Assembly (GAMA) Survey, and the VST ATLAS Survey. The SAMI Galaxy Survey is supported by the Australian Research Council Centre of Excellence for All Sky Astrophysics in 3 Dimensions (ASTRO 3D), through project number CE170100013, the Australian Research Council Centre of Excellence for All-sky Astrophysics (CAASTRO), through project number CE110001020, and other participating institutions. The SAMI Galaxy Survey website is http://sami-survey.org/.
M.S.O. acknowledges the funding support from the Australian Research Council (ARC) through a Future Fellowship (FT140100255). J.T.A. acknowledges the award of a Science and Industry Endowment Fund (SIEF) John Stocker Fellowship. J.v.d.S. is funded under Bland-Hawthorn’s ARC Laureate Fellowship (FL140100278). S.B. acknowledges the funding support from the Australian Research Council through a Future Fellowship (FT140101166). S.K.Y. acknowledges support from the Korean National Research Foundation (2017R1A2A1A05001116) and by the Yonsei University Future Leading Research Initiative (2015-22-0064). This study was performed under the umbrella of the joint collaboration between Yonsei University Observatory and the Korean Astronomy and Space Science Institute. C.F. gratefully acknowledges funding provided by the Australian Research Council’s Discovery Projects (grants DP150104329 and DP170100603). Support for A.M.M. is provided by National Aeronautics and Space Ad-minsitration (NASA) through Hubble Fellowship grant #HST-HF2-51377 awarded by the Space Telescope Science Institute, which is operated by the Association of Universities for Research in Astronomy, Inc., for NASA, under contract NAS5-26555.
All Science Journal Classification (ASJC) codes
- Astronomy and Astrophysics
- Space and Planetary Science