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

Crossett, Jacob P. and Pimbblet, Kevin A. and Jones, D. Heath and Brown, Michael J. I. and Stott, John P. (2017) Near-ultraviolet signatures of environment-driven galaxy quenching in Sloan Digital Sky Survey groups. Monthly Notices of the Royal Astronomical Society, 464 (1). pp. 480-490. ISSN 0035-8711

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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 >4 sigma difference in the distribution of (NUV - r) colours, and an (NUV - r) blue fraction >3 sigma higher outside groups. A comparison of satellite and non-grouped samples has found the NUV fraction is a factor of similar to 2 lower for satellite galaxies between 10(10.5) and 10(10.7)M(circle dot), 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 Sersic 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 (similar to 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.

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Monthly Notices of the Royal Astronomical Society
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27 Mar 2017 13:34
Last Modified:
22 Nov 2022 04:32