Fast and slow paths to quiescence : ages and sizes of 400 quiescent galaxies from the LEGA-C survey

Wu, Po-Feng
van der Wel, Arjen
Bezanson, Rachel
Gallazzi, Anna
Pacifici, Camilla
Straatman, Caroline M. S.
Barišić, Ivana
Bell, Eric F.
Chauke, Priscilla
van Houdt, Josha
Franx, Marijn
Muzzin, Adam
Sobral, David
Wild, Vivienne

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Publication date

September 2018

DOI

10.3847/1538-4357/aae822

Publisher

American Astronomical Society

Journal

The Astrophysical Journal

Abstract

Funding: VW acknowledges funding from the ERC (starting grant SEDmorph, PI. Wild)We analyze stellar age indicators (Dn4000 and EW(Hδ)) and sizes of 467 quiescent galaxies with M∗≥1010M⊙ at z∼0.7 drawn from DR2 of the LEGA-C survey. Interpreting index variations in terms of equivalent single stellar population age, we find that the median stellar population is younger for larger galaxies at fixed stellar mass. The effect is significant, yet small; the ages of the larger and the smaller subsets differ by only<500 Myr, much less than the age variation among individual galaxies (∼1.5 Gyr). At the same time, quiescent galaxies with the strongest Hδ absorption —those experienced recent and rapid quenching events — tend to be smaller than the aver...