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

• Published in: Monthly Notices of the Royal Astronomical Society
• Main Authors: Barone, Tania M., D'Eugenio, Francesco, Scott, Nicholas, Colless, Matthew, Vaughan, Sam P., van der Wel, Arjen, Fraser-McKelvie, Amelia, de Graaff, Anna, van de Sande, Jesse, Wu(吳柏鋒), Po-Feng, Bezanson, Rachel, Brough, Sarah, Bell, Eric, Croom, Scott M., Cortese, Luca, Driver, Simon, Gallazzi, Anna R., Muzzin, Adam, Sobral, David, Bland-Hawthorn, Joss, Bryant, Julia J., Goodwin, Michael, Lawrence, Jon S., Lorente, Nuria P. F., Owers, Matt S.
• Other Authors: Swinburne University of Technology
• Format: Article in Journal/Newspaper
• Language: unknown
• Published: Oxford University Press (OUP) 2022
• Subjects: sami
• Online Access: http://hdl.handle.net/1959.3/466831; https://doi.org/10.1093/mnras/stac705

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 masssize plane, using the stellar mass M-* and a dynamical mass proxy derived from the virial theorem M-D proportional to sigma(2) R-e. We find that, similarly to at low redshift, the metallicity of quiescent galaxies at 0.60 <= z <= 0.76 closely correlates with M/R-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 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/R-e(2)) at 0.60 <= z <= 0.76, despite this relation being strong at low redshift. We consider this change in the age-M/R-e(2) 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 similar to 0 age-M/R-e(2) 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.