ZFOURGE: Using Composite Spectral Energy Distributions to Characterize Galaxy Populations at 1 < z < 4
Article
Article Title | ZFOURGE: Using Composite Spectral Energy Distributions to Characterize Galaxy Populations at 1 < z < 4 |
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ERA Journal ID | 1057 |
Article Category | Article |
Authors | Forrest, Ben, Tran, Kim-Vy H., Broussard, Adam, Cohn, Jonathan H., Kennicutt, Robert C., Papovich, Casey, Allen, Rebecca, Cowley, Michael, Glazebrook, Karl, Kacprzak, Glenn G., Kawinwanichakij, Lalitwadee, Nanayakkara, Themiya, Salmon, Brett, Spitler, Lee R. and Straatman, Caroline M. S. |
Journal Title | The Astrophysical Journal: an international review of astronomy and astronomical physics |
Journal Citation | 863 (2), pp. 1-25 |
Article Number | 131 |
Number of Pages | 25 |
Year | 2018 |
Publisher | IOP Publishing |
Place of Publication | United States |
ISSN | 0004-637X |
1538-4357 | |
Digital Object Identifier (DOI) | https://doi.org/10.3847/1538-4357/aad232 |
Web Address (URL) | https://iopscience.iop.org/article/10.3847/1538-4357/aad232 |
Abstract | We investigate the properties of galaxies as they shut off star formation over the 4 billion years surrounding peak cosmic star formation. To do this, we categorize ∼7000 galaxies from 1 < z < 4 into 90 groups based on the shape of their spectral energy distributions (SEDs) and build composite SEDs with R ∼ 50 resolution. These composite SEDs show a variety of spectral shapes and also show trends in parameters such as color, mass, star formation rate, and emission-line equivalent width. Using emission-line equivalent widths and strength of the 4000 Å break, , we categorize the composite SEDs into five classes: extreme emission line, star-forming, transitioning, post-starburst, and quiescent galaxies. The transitioning population of galaxies shows modest Hα emission (EWREST ∼ 40 Å) compared to more typical star-forming composite SEDs at log10(M/M o) ∼ 10.5 (EWREST ∼ 80 Å). Together with their smaller sizes (3 kpc vs. 4 kpc) and higher Sérsic indices (2.7 vs. 1.5), this indicates that morphological changes initiate before the cessation of star formation. The transitional group shows a strong increase of over 1 dex in number density from z ∼ 3 to z ∼ 1, similar to the growth in the quiescent population, while post-starburst galaxies become rarer at z ≲ 1.5. We calculate average quenching timescales of 1.6 Gyr at z ∼ 1.5 and 0.9 Gyr at z ∼ 2.5 and conclude that a fast-quenching mechanism producing post-starbursts dominated the quenching of galaxies at early times, while a slower process has become more common since z ∼ 2. |
Keywords | galaxies: evolution; galaxies: high-redshift |
Funder | Australian Research Council |
Byline Affiliations | Texas A&M University, United States |
University of New South Wales | |
Australian Astronomical Observatory, Australia | |
State University of New Jersey, United States | |
University of Arizona, United States | |
Swinburne University of Technology | |
Macquarie University | |
Leiden University, Netherlands | |
Space Telescope Science Institute, United States | |
University of Gent, Belgium |
https://research.usq.edu.au/item/w45ww/zfourge-using-composite-spectral-energy-distributions-to-characterize-galaxy-populations-at-1-z-4
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