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Galaxy And Mass Assembly (GAMA): Timescales for galaxies crossing the green valley

Phillipps, S, Bremer, MN, Hopkins, AM, Propris, RD, Taylor, EN, James, PA, Davies, LJM, Cluver, M, Driver, SP, Eales, SA, Holwerda, BW, Kelvin, LS and Sansom, AE (2019) Galaxy And Mass Assembly (GAMA): Timescales for galaxies crossing the green valley. Monthly Notices of the Royal Astronomical Society, 485 (4). pp. 5559-5572. ISSN 0035-8711

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We explore the constraints that can be placed on the evolutionary timescales for typical low redshift galaxies evolving from the blue cloud through the green valley and onto the red sequence. We utilise galaxies from the GAMA survey with 0.1 < z < 0.2 and classify them according to the intrinsic (u-r?) colours of their stellar populations, as determined by fits to their multi-wavelength spectral energy distributions. Using these fits to also determine stellar population ages and star formation timescales, we argue that our results are consistent with a green valley population dominated by galaxies that are simply decreasing their star formation (running out of gas) over a timescale of 2-4 Gyr which are seen at a specific epoch in their evolution (approximately 1.6 e-folding times after their peak in star formation). If their fitted star formation histories are extrapolated forwards, the green galaxies will further redden over time, until they attain the colours of a passive population. In this picture, no specific quenching event which cuts-off their star formation is required, though it remains possible that the decline in star formation in green galaxies may be expedited by internal or external forces. However, there is no evidence that green galaxies have recently changed their star formation timescales relative to their previous longer term star formation histories.

Item Type: Article
Additional Information: This article has been accepted for publication in Monthly Notices of the Royal Astronomical Society ©: 2019 The Authors Published by Oxford University Press on behalf of the Royal Astronomical Society. All rights reserved.
Uncontrolled Keywords: 0201 Astronomical and Space Sciences
Subjects: Q Science > QB Astronomy
Q Science > QC Physics
Divisions: Astrophysics Research Institute
Publisher: Oxford University Press
Related URLs:
Date Deposited: 28 Mar 2019 09:38
Last Modified: 04 Sep 2021 09:33
DOI or ID number: 10.1093/mnras/stz799
URI: https://researchonline.ljmu.ac.uk/id/eprint/10445
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