Fast, Slow, Early, Late: Quenching Massive Galaxies at z ∼0.8

Authors

• Sandro Tacchella, Harvard-Smithsonian Center for Astrophysics
• Charlie Conroy, Harvard-Smithsonian Center for Astrophysics
• S. M. Faber, University of California, Santa Cruz
• Benjamin D. Johnson, Harvard-Smithsonian Center for Astrophysics
• Joel Leja, Pennsylvania State University
• Guillermo Barro, University of the PacificFollow
• Emily C. Cunningham, Simons Foundation
• Alis J. Deason, Durham University
• Puragra Guhathakurta, University of California, Santa Cruz
• Yicheng Guo, University of Missouri
• Lars Hernquist, Harvard-Smithsonian Center for Astrophysics
• David C. Koo, University of California, Santa Cruz
• Kevin McKinnon, University of California, Santa Cruz
• Constance M. Rockosi, University of California, Santa Cruz
• Joshua S. Speagle, University of Toronto
• Pieter Van Dokkum, Yale University
• Hassen M. Yesuf, Peking University

Document Type

Article

Publication Title

Astrophysical Journal

Department

Physics

ISSN

15384357

Volume

926

Issue

2

DOI

10.3847/1538-4357/ac449b

First Page

1

Last Page

36

Publication Date

2-18-2022

Abstract

We investigate the stellar populations for a sample of 161 massive, mainly quiescent galaxies at z obs = 0.8 with deep Keck/DEIMOS rest-frame optical spectroscopy (HALO7D survey). With the fully Bayesian framework Prospector, we simultaneously fit the spectroscopic and photometric data with an advanced physical model (including nonparametric star formation histories, emission lines, variable dust attenuation law, and dust and active galactic nucleus emission), together with an uncertainty and outlier model. We show that both spectroscopy and photometry are needed to break the dust-age-metallicity degeneracy. We find a large diversity of star formation histories: although the most massive (M > 2 × 1011 M) galaxies formed the earliest (formation redshift of z f ≈ 5-10 with a short star formation timescale of τ SF ≥2 1 Gyr), lower-mass galaxies have a wide range of formation redshifts, leading to only a weak trend of z f with M. Interestingly, several low-mass galaxies have formation redshifts of z f ≈ 5-8. Star-forming galaxies evolve about the star-forming main sequence, crossing the ridgeline several times in their past. Quiescent galaxies show a wide range and continuous distribution of quenching timescales (τ quench ≈ 0-5 Gyr) with a median of τquench=1.0-0.9+0.8Gyr and of quenching epochs of z quench ≈ 0.8-5.0 (zquench=1.3-0.4+0.7). This large diversity of quenching timescales and epochs points toward a combination of internal and external quenching mechanisms. In our sample, rejuvenation and "late bloomers"are uncommon. In summary, our analysis supports the "grow-and-quench"framework and is consistent with a wide and continuously populated diversity of quenching timescales.

Creative Commons License

This work is licensed under a Creative Commons Attribution 4.0 International License.

Recommended Citation

Tacchella, Sandro; Conroy, Charlie; Faber, S. M.; Johnson, Benjamin D.; Leja, Joel; Barro, Guillermo; Cunningham, Emily C.; Deason, Alis J.; Guhathakurta, Puragra; Guo, Yicheng; Hernquist, Lars; Koo, David C.; McKinnon, Kevin; Rockosi, Constance M.; Speagle, Joshua S.; Van Dokkum, Pieter; and Yesuf, Hassen M., "Fast, Slow, Early, Late: Quenching Massive Galaxies at z ∼0.8" (2022). Pacific Faculty Work. 199.
https://scholarlycommons.pacific.edu/all-faculty/199