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The structure of post-starburst galaxies at 0.5 < z < 2: evidence for two distinct quenching routes at different epochs

Maltby, David T.; Almaini, Omar; Wild, Vivienne; Hatch, Nina A.; Hartley, William G.; Simpson, Chris; Rowlands, Kate; Socolovsky, Miguel

Authors

David T. Maltby

Omar Almaini

Vivienne Wild

Nina A. Hatch

William G. Hartley

Chris Simpson

Kate Rowlands

Miguel Socolovsky

Abstract

We present an analysis of the structure of post-starburst (PSB) galaxies in the redshift range 0.5 less than z less than 2, using a photometrically selected sample identified in the Ultra Deep Survey field. We examine the structure of ∼80 of these transient galaxies using radial light μ(r) profiles obtained from CANDELS Hubble Space Telescope near-infrared/optical imaging, and compare to a large sample of ∼2000 passive and star-forming galaxies. For each population, we determine their typical structural properties (effective radius re, Sersic index n) and find significant differences in PSB structure at different epochs. At high redshift (z>1), PSBs are typically massive (M∗>1010M), very compact and exhibit high Sersic indices, with structures that differ significantly from their star-forming progenitors but are similar to massivepassive galaxies. In contrast, at lower redshift (0.5 less than z less than 1), PSBs are generally of low mass(M∗ less than 1010M) and exhibit compact but less concentrated profiles (i.e. lower Sersic indices), with structures similar to low-mass passive discs. Furthermore, for both epochs, we find remarkably consistent PSB structure across the optical/near-infrared wavebands (which largely trace different stellar populations), suggesting that any preceding starburst and/or quenchingin PSBs was not strongly centralized. Taken together, these results imply that PSBs at z>1 have been recently quenched during a major disruptive event (e.g. merger or protogalactic collapse) that formed a compact remnant, while at z less than 1 an alternative less disruptive process is primarily responsible. Our results suggest that high-z PSBs are an intrinsically different population to those at lower redshifts, and indicate different quenching routes are active at different epochs.

Journal Article Type Article
Publication Date Oct 11, 2018
Journal Monthly Notices of the Royal Astronomical Society
Print ISSN 0035-8711
Electronic ISSN 1365-2966
Publisher Oxford University Press
Peer Reviewed Peer Reviewed
Volume 480
Issue 1
Pages 381-401
DOI https://doi.org/10.1093/mnras/sty1794
Keywords galaxies: evolution, galaxies: fundamental parameters, galaxies: high-redshift, galaxies: structure
Publisher URL https://academic.oup.com/mnras/article/480/1/381/5049326
Related Public URLs http://eprints.nottingham.ac.uk/53273/
Additional Information This article has been accepted for publication in Monthly Notices of the Royal Astronomial Society ©: 2018 The Author(s) Published by Oxford University Press on behalf of the Royal Astronomical Society. All rights reserved.

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Copyright Statement
This article has been accepted for publication in Monthly Notices of the Royal Astronomical Society ©:2018 The Author(s) Published by Oxford University Press on behalf of the Royal Astronomical Society. All rights reserved.



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