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Near-ultraviolet signatures of environment-driven galaxy quenching in Sloan Digital Sky Survey groups

Crossett, Jacob P.; Pimbblet, Kevin A.; Jones, D. Heath; Brown, Michael J.I.; Stott, John P.

Abstract

© 2016 The Authors. Published by Oxford University Press on behalf of the Royal Astronomical Society. We have investigated the effect of group environment on residual star formation in galaxies, using Galaxy Evolution Explorer near-ultraviolet (NUV) galaxy photometry with the Sloan Digital Sky Survey group catalogue of Yang et al. We compared the (NUV - r) colours of grouped and non-grouped galaxies, and find a significant increase in the fraction of red sequence galaxies with blue (NUV - r) colours outside of groups. When comparing galaxies in mass-matched samples of satellite (non-central), and non-grouped galaxies, we found a > 4σ difference in the distribution of (NUV - r) colours, and an (NUV - r) blue fraction > 3σ higher outside groups. A comparison of satellite and non-grouped samples has found the NUV fraction is a factor of ~2 lower for satellite galaxies between 10 10.5 and 10 10.7 M ⊙ , showing that higher mass galaxies are more likely to have residual star formation when not influenced by a group potential. There was a higher (NUV - r) blue fraction of galaxies with lower Sérsic indices (n < 3) outside of groups, not seen in the satellite sample. We have used stellar population models of Bruzual & Charlot with multiple burst, or exponentially declining star formation histories to find that many of the (NUV - r) blue non-grouped galaxies can be explained by a slow (~2 Gyr) decay of star formation, compared to the satellite galaxies. We suggest that taken together, the difference in (NUV - r) colours between samples can be explained by a population of secularly evolving, non-grouped galaxies, where star formation declines slowly. This slow channel is less prevalent in group environments where more rapid quenching can occur.

Journal Article Type Article
Publication Date Jan 1, 2017
Journal Monthly notices of the Royal Astronomical Society
Print ISSN 0035-8711
Electronic ISSN 1365-2966
Publisher Oxford University Press (OUP)
Peer Reviewed Peer Reviewed
Volume 464
Issue 1
Pages 480-490
DOI https://doi.org/10.1093/mnras/stw2228
Keywords Galaxies : evolution, Galaxies : groups : general, Galaxies : photometry, Galaxies : star formation, Galaxies : stellar content, Ultraviolet : galaxies
Publisher URL http://mnras.oxfordjournals.org/content/early/2016/09/07/mnras.stw2228
Additional Information This is a pre-copyedited, author-produced PDF of an article accepted for publication in Monthly notices of the Royal Astronomical Society following peer review.

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