TY - JOUR
T1 - Fast, Slow, Early, Late
T2 - Quenching Massive Galaxies at z ∼0.8
AU - Tacchella, Sandro
AU - Conroy, Charlie
AU - Faber, S. M.
AU - Johnson, Benjamin D.
AU - Leja, Joel
AU - Barro, Guillermo
AU - Cunningham, Emily C.
AU - Deason, Alis J.
AU - Guhathakurta, Puragra
AU - Guo, Yicheng
AU - Hernquist, Lars
AU - Koo, David C.
AU - McKinnon, Kevin
AU - Rockosi, Constance M.
AU - Speagle, Joshua S.
AU - Van Dokkum, Pieter
AU - Yesuf, Hassen M.
N1 - Funding Information:
This work has made use of the Rainbow Cosmological Surveys Database, which is operated by the Centro de Astrobiología (CAB/INTA), partnered with the University of California Observatories at Santa Cruz (UCO/Lick, UCSC). Some of the data presented herein were obtained at the W. M. Keck Observatory, which is operated as a scientific partnership among the California Institute of Technology, the University of California, and the National Aeronautics and Space Administration. The Observatory was made possible by the generous financial support of the W. M. Keck Foundation. The authors wish to recognize and acknowledge the very significant cultural role and reverence that the summit of Maunakea has always had within the indigenous Hawaiian community. We are most fortunate to have the opportunity to conduct observations from this mountain.
Funding Information:
We thank the referee for a thorough report on a lengthy paper that greatly improved and strengthened this work. We are grateful to Margaret Geller, Sirio Belli, Reinhard Genzel, Kartheik Iyer, Dylan Nelson, Erica Nelson, and Annalisa Pillepich for productive discussions and comments. S.T. is supported by the Smithsonian Astrophysical Observatory through the CfA Fellowship and by the 2021 Research Fund 1.210134.01 of UNIST (Ulsan National Institute of Science & Technology). S.M.F., G.B., Y.G., D.C.K., and H.M.Y. received partial support from NSF grants AST-0808133 and AST-1615730. E.C.C. is supported by a Flatiron Research Fellowship at the Flatiron Institute, which is supported by the Simons Foundation.
Publisher Copyright:
© 2022. The Author(s). Published by the American Astronomical Society.
PY - 2022/2/1
Y1 - 2022/2/1
N2 - 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.
AB - 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.
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U2 - 10.3847/1538-4357/ac449b
DO - 10.3847/1538-4357/ac449b
M3 - Article
AN - SCOPUS:85125745015
SN - 0004-637X
VL - 926
JO - Astrophysical Journal
JF - Astrophysical Journal
IS - 2
M1 - 134
ER -