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The LEGA-C of Nature and Nurture in Stellar Populations at z ∼ 0.6–1.0: D_n4000 and Hδ Reveal Different Assembly Histories for Quiescent Galaxies in Different Environments

Sobral, David and van der Wel, Arjen and Bezanson, Rachel and Bell, Eric and Muzzin, Adam and D’Eugenio, Francesco and Darvish, Behnam and Gallazzi, Anna and Wu, Po-Feng and Maseda, Michael and Matthee, Jorryt and Paulino-Afonso, Ana and Straatman, Caroline and van Dokkum, Pieter G. (2022) The LEGA-C of Nature and Nurture in Stellar Populations at z ∼ 0.6–1.0: D_n4000 and Hδ Reveal Different Assembly Histories for Quiescent Galaxies in Different Environments. Astrophysical Journal, 926 (2). Art. No. 117. ISSN 0004-637X. doi:10.3847/1538-4357/ac4419.

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Galaxy evolution is driven by a variety of physical processes that are predicted to proceed at different rates for different dark matter haloes and environments across cosmic times. A record of this evolution is preserved in galaxy stellar populations, which we can access using absorption-line spectroscopy. Here we explore the large LEGA-C survey (DR3) to investigate the role of the environment and stellar mass on stellar populations at z ∼ 0.6–1 in the COSMOS field. Leveraging the statistical power and depth of LEGA-C, we reveal significant gradients in D_n4000 and Hδ equivalent widths (EWs) distributions over the stellar mass versus environment 2D spaces for the massive galaxy population (M > 10¹⁰ M_⊙) at z ∼ 0.6–1.0. D_n4000 and Hδ EWs primarily depend on stellar mass, but they also depend on environment at fixed stellar mass. By splitting the sample into centrals and satellites, and in terms of star-forming galaxies and quiescent galaxies, we reveal that the significant environmental trends of D_n4000 and Hδ EW, when controlling for stellar mass, are driven by quiescent galaxies. Regardless of being centrals or satellites, star-forming galaxies reveal D_n4000 and Hδ EWs, which depend strongly on their stellar mass and are completely independent of the environment at 0.6 z < 1.0. The environmental trends seen for satellite galaxies are fully driven by the trends that hold only for quiescent galaxies, combined with the strong environmental dependency of the quiescent fraction at fixed stellar mass. Our results are consistent with recent predictions from simulations that point toward massive galaxies forming first in overdensities or the most compact dark matter haloes.

Item Type:Article
Related URLs:
URLURL TypeDescription Paper
Sobral, David0000-0001-8823-4845
van der Wel, Arjen0000-0002-5027-0135
Bezanson, Rachel0000-0001-5063-8254
Bell, Eric0000-0002-5564-9873
Muzzin, Adam0000-0002-9330-9108
D’Eugenio, Francesco0000-0003-2388-8172
Darvish, Behnam0000-0003-4919-9017
Gallazzi, Anna0000-0002-9656-1800
Wu, Po-Feng0000-0002-9665-0440
Matthee, Jorryt0000-0003-2871-127X
Paulino-Afonso, Ana0000-0002-0943-0694
Straatman, Caroline0000-0001-5937-4590
van Dokkum, Pieter G.0000-0002-8282-9888
Additional Information:© 2022. The Author(s). Published by the American Astronomical Society. Original content from this work may be used under the terms of the Creative Commons Attribution 4.0 licence. Any further distribution of this work must maintain attribution to the author(s) and the title of the work, journal citation and DOI. Received 2021 November 1; revised 2021 December 10; accepted 2021 December 15; published 2022 February 17. We thank the reviewer for several valuable comments that improved the clarity of the manuscript. P.F.W. acknowledges the support of the fellowship by the East Asian Core Observatories Association. This work is based on observations made with ESO VLT Telescopes at the La Silla Paranal Observatory under programmes ID 194-A.2005 and 1100.A-0949 (The LEGA-C Public Spectroscopy Survey). This project has received funding from the European Research Council (ERC) under the European Union—Horizon 2020 research and innovation program (grant agreement No. 683184).
Funding AgencyGrant Number
East Asian Core Observatories Association (EACOA)UNSPECIFIED
European Research Council (ERC)683184
Subject Keywords:Galaxy ages; Galaxy environments; Extragalactic astronomy; Galaxy evolution; Galaxy groups; Galaxy quenching
Issue or Number:2
Classification Code:Unified Astronomy Thesaurus concepts: Galaxy ages (576); Galaxy environments (2029); Extragalactic astronomy (506); Galaxy evolution (594); Galaxy groups (597); Galaxy quenching (2040)
Record Number:CaltechAUTHORS:20220217-686399000
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Official Citation:David Sobral et al 2022 ApJ 926 117
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:113487
Deposited By: George Porter
Deposited On:17 Feb 2022 21:47
Last Modified:17 Feb 2022 21:47

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