Evolution in the orbital structure of quiescent galaxies from MAGPI, LEGA-C and SAMI surveys: direct evidence for merger-driven growth over the last 7 Gy

Author(s)

Francesco D'Eugenio, Arjen van der Wel, Joanna M. Piotrowska, Rachel Bezanson, Edward N. Taylor, Jesse van de Sande, William M. Baker, Eric F. Bell, Sabine Bellstedt, Joss Bland-Hawthorn, Asa F. L. Bluck, Sarah Brough, Julia J. Bryant, Matthew Colless, Luca Cortese, Scott M. Croom, Caro Derkenne, Pieter van Dokkum, Deanne Fisher, Caroline Foster, Anna Gallazzi, Anna de Graaff, Brent Groves, Josha van Houdt, Claudia del P. Lagos, Tobias J. Looser, Roberto Maiolino, Michael Maseda, J. Trevor Mendel, Angelos Nersesian, Camilla Pacifici, Adriano Poci, Rhea-Silvia Remus, Sarah M. Sweet, Sabine Thater, Kim-Vy Tran, Hannah Übler, Lucas M. Valenzuela, Emily Wisnioski, Stefano Zibetti

Abstract

We present the first study of spatially integrated higher-order stellar kinematics over cosmic time. We use deep rest-frame optical spectroscopy of quiescent galaxies at redshifts z = 0.05, 0.3, and 0.8 from the SAMI, MAGPI, and LEGA-C surveys to measure the excess kurtosis h

₄ of the stellar velocity distribution, the latter parametrized as a Gauss-Hermite series. Conservatively using a redshift-independent cut in stellar mass () and matching the stellar-mass distributions of our samples, we find 7σ evidence of h

₄ increasing with cosmic time, from a median value of 0.019 ± 0.002 at z = 0.8 to 0.059 ± 0.004 at z = 0.06. Alternatively, we use a physically motivated sample selection based on the mass distribution of the progenitors of local quiescent galaxies as inferred from numerical simulations; in this case, we find 10σ evidence. This evolution suggests that, over the last 7 Gyr, there has been a gradual decrease in the rotation-to-dispersion ratio and an increase in the radial anisotropy of the stellar velocity distribution, qualitatively consistent with accretion of gas-poor satellites. These findings demonstrate that massive galaxies continue to accrete mass and increase their dispersion support after becoming quiescent.

Organisation(s)

Department of Astrophysics

External organisation(s)

University of Cambridge, Ghent University , University of Pittsburgh, Swinburne University of Technology, The University of Sydney, ARC Centre of Excellence for All Sky Astrophysics in 3 Dimensions (ASTRO 3D), University of Michigan, University of Western Australia, Florida International University, University of New South Wales, Australian National University, Macquarie University, Yale University, INAF - Osservatorio Astrofisico di Arcetri, Leiden University, Max-Planck-Institut für Astronomie, University College London, University of Wisconsin, Madison, Space Telescope Science Institute, Durham University, Ludwig-Maximilians-Universität München, University of Queensland, Texas A&M University

Journal

Monthly Notices of the Royal Astronomical Society

Volume

525

Pages

2789-2805

No. of pages

17

ISSN

0035-8711

DOI

https://doi.org/10.1093/mnras/stad800

Publication date

10-2023

Peer reviewed

Yes

Austrian Fields of Science 2012

103003 Astronomy, 103004 Astrophysics

Keywords

ASJC Scopus subject areas

Astronomy and Astrophysics, Space and Planetary Science

Portal url

https://ucrisportal.univie.ac.at/en/publications/57b272fa-3f22-46d1-86f2-f44a38aec5a9