The LEGA-C and SAMI Galaxy Surveys: Quiescent Stellar Populations and the Mass-Size Plane across 6 Gyr
Journal
Monthly Notices of the Royal Astronomical Society
Journal Volume
512
Journal Issue
3
Date Issued
2021-07-02
Author(s)
Tania M. Barone
Francesco D'Eugenio
Nicholas Scott
Matthew Colless
Sam P. Vaughan
Arjen van der Wel
Amelia Fraser-McKelvie
Anna de Graaff
Jesse van de Sande
Rachel Bezanson
Sarah Brough
Eric Bell
Scott M. Croom
Luca Cortese
Simon Driver
Anna R. Gallazzi
Adam Muzzin
David Sobral
Joss Bland-Hawthorn
Julia J. Bryant
Michael Goodwin
Jon S. Lawrence
Nuria P. F. Lorente
Matt S. Owers
Abstract
We investigate the change in mean stellar population age and metallicity
([Z/H]) scaling relations for quiescent galaxies from intermediate redshift
($0.60\leq z\leq0.76$) using the LEGA-C Survey, to low redshift ($0.014\leq
z\leq0.10$) using the SAMI Galaxy Survey. We find that, similarly to their
low-redshift counterparts, the stellar metallicity of quiescent galaxies at
$0.60\leq z\leq 0.76$ closely correlates with $M_*/R_\mathrm{e}$ (a proxy for
the gravitational potential or escape velocity), in that galaxies with deeper
potential wells are more metal-rich. This supports the hypothesis that the
relation arises due to the gravitational potential regulating the retention of
metals, by determining the escape velocity required by metal-rich stellar and
supernova ejecta to escape the system and avoid being recycled into later
stellar generations. On the other hand, we find no correlation between stellar
age and $M_*/R_\mathrm{e}^2$ (stellar mass surface density $\Sigma$) in the
LEGA-C sample, despite this being a strong relation at low redshift. We
consider this change in the age--$\Sigma$ relation in the context of the
redshift evolution of the star-forming and quiescent populations in the
mass--size plane, and find our results can be explained as a consequence of
galaxies forming more compactly at higher redshifts, and remaining compact
throughout their evolution. Furthermore, galaxies appear to quench at a
characteristic surface density that decreases with decreasing redshift. The
$z\sim 0$ age--$\Sigma$ relation is therefore a result of building up the
quiescent and star-forming populations with galaxies that formed at a range of
redshifts and so a range of surface densities.
Subjects
galaxies: abundances | galaxies: evolution | galaxies: fundamental parameters | galaxies: statistics | galaxies: stellar content | galaxies: structure; astro-ph.GA; astro-ph.GA
Description
18 pages, 11 figures, accepted to MNRAS
Type
journal article