The LEGA-C and SAMI galaxy surveys: quiescent stellar populations and the mass-size plane across 6 Gyr

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, Po Feng Wu, Rachel Bezanson, Sarah Brough, Eric Bell, Scott M. Croom, Luca Cortese, Simon Driver, Anna R. Gallazzi, Adam Muzzin, David Sobral, Joss Bland-HawthornJulia J. Bryant, Michael Goodwin, Jon S. Lawrence, Nuria P.F. Lorente, Matt S. Owers

*Corresponding author for this work

    Research output: Contribution to journalArticlepeer-review

    20 Citations (Scopus)

    Abstract

    We investigate changes in stellar population age and metallicity ([Z/H]) scaling relations for quiescent galaxies from intermediate redshift (0.60 ≤ z ≤ 0.76) using the LEGA-C Survey to low redshift (0.014 ≤ z ≤ 0.10) using the SAMI Galaxy Survey. Specifically, we study how the spatially integrated global age and metallicity of individual quiescent galaxies vary in the mass-size plane, using the stellar mass M∗ and a dynamical mass proxy derived from the virial theorem MD α σ2 Re. We find that, similarly to at low redshift, the metallicity of quiescent galaxies at 0.60 ≤ z ≤ 0.76 closely correlates with M/Re (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 for metal-rich stellar and supernova ejecta to escape the system and avoid being recycled into later stellar generations. Conversely, we find no correlation between age and surface density (M/Re2) at 0.60 ≤ z ≤ 0.76, despite this relation being strong at low redshift. We consider this change in the age-M/Re2 relation in the context of the redshift evolution of the star-forming and quiescent mass-size relations, and find our results are consistent with 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 ∼ 0 age-M/Re2 relation is therefore a result of building up the quiescent and star-forming populations with galaxies that formed at a range of redshifts and therefore a range of surface densities.

    Original languageEnglish
    Pages (from-to)3828-3845
    Number of pages18
    JournalMonthly Notices of the Royal Astronomical Society
    Volume512
    Issue number3
    DOIs
    Publication statusPublished - 1 May 2022

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