Massive post-starburst galaxies at z > 1 are compact proto-spheroids

Almaini, Omar and Wild, Vivienne and Maltby, David T. and Hartley, William G. and Simpson, Chris and Hatch, Nina A. and McLure, Ross J. and Dunlop, James S. and Rowlands, Kate (2017) Massive post-starburst galaxies at z > 1 are compact proto-spheroids. Monthly Notices of the Royal Astronomical Society, 472 (1). pp. 1401-1412. ISSN 1365-2966

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Abstract

We investigate the relationship between the quenching of star formation and the structural transformation of massive galaxies, using a large sample of photometrically-selected poststarburst galaxies in the UKIDSS UDS field. We find that post-starburst galaxies at highredshift (z > 1) show high Sérsic indices, significantly higher than those of active star-forming galaxies, but with a distribution that is indistinguishable from the old quiescent population. We conclude that the morphological transformation occurs before (or during) the quenching of star formation. Recently quenched galaxies are also the most compact; we find evidence that massive post-starburst galaxies (M_ > 1010:5 M_) at high redshift (z > 1) are on average smaller than comparable quiescent galaxies at the same epoch. Our findings are consistent with a scenario in which massive passive galaxies are formed from three distinct phases: (1) gas-rich dissipative collapse to very high densities, forming the proto-spheroid; (2) rapid quenching of star formation, to create the “red nugget” with post-starburst features; (3) a gradual growth in size as the population ages, perhaps as a result of minor mergers.

Item Type: Article
Additional Information: This article has been accepted for publication in Monthly Notices of the Royal Astronomical Society Published by Oxford University Press on behalf of the Royal Astronomical Society.
Keywords: galaxies: evolution – galaxies: formation – galaxies: fundamental parameters – galaxies: structure – galaxies: high-redshift
Schools/Departments: University of Nottingham, UK > Faculty of Science > School of Physics and Astronomy
Identification Number: 10.1093/mnras/stx1957
Depositing User: Eprints, Support
Date Deposited: 07 Sep 2017 10:55
Last Modified: 18 Oct 2017 18:11
URI: http://eprints.nottingham.ac.uk/id/eprint/45532

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