CEERS Key Paper. IV. A Triality in the Nature of HST-dark Galaxies
Papovich, Casey; Yang, Guang; Finkelstein, Steven L.; Barro, Guillermo; Buat, Véronique; Pérez-González, Pablo G.; Arrabal Haro, Pablo; Bagley, Micaela B.; Bell, Eric F.; Bisigello, Laura; Calabrò, Antonello; Casey, Caitlin M.; Cleri, Nikko J.; Costantin, Luca; Cooper, M. C.; Dickinson, Mark; Ferguson, Henry C.; Fontana, Adriano; Giavalisco, Mauro; Grazian, Andrea; Grogin, Norman A.; Kartaltepe, Jeyhan S.; Kewley, Lisa J.; Kirkpatrick, Allison; Kocevski, Dale D.; Koekemoer, Anton M.; Long, Arianna S.; Lucas, Ray A.; Pirzkal, Nor; Ravindranath, Swara; Somerville, Rachel S.; Trump, Jonathan R.; Wilkins, Stephen M.; Yung, L. Y. Aaron; Zavala, Jorge A.; Gardner, Jonathan P.; Annunziatella, Marianna; García-Argumánez, Ángela; Tacchella, Sandro; Wuyts, Stijn; Lotz, Jennifer M.; McGrath, Elizabeth J.; Behroozi, Peter; Dekel, Avishai; Jogee, Shardha; Elbaz, David; Huertas-Company, Marc; Backhaus, Bren E.; Gómez-Guijarro, Carlos; Franco, Maximilien; Cooray, Asantha R.; Wang, Weichen; Guo, Yuchen; Mérida, Rosa M.; Coogan, Rosemary T.
Spain, United States, Japan, Italy, France, Israel, United Kingdom, Malta, Netherlands
Abstract
The new capabilities that JWST offers in the near- and mid-infrared (IR) are used to investigate in unprecedented detail the nature of optical/near-IR-faint, mid-IR-bright sources, with HST-dark galaxies among them. We gather JWST data from the CEERS survey in the Extended Groth Strip, jointly with HST data, and analyze spatially resolved optical-to-mid-IR spectral energy distributions to estimate photometric redshifts in two dimensions and stellar population properties on a pixel-by-pixel basis for red galaxies detected by NIRCam. We select 138 galaxies with F150W ‑ F356W > 1.5 mag and F356W < 27.5 mag. The nature of these sources is threefold: (1) 71% are dusty star-forming galaxies (SFGs) at 2 < z < 6 with and a variety of specific SFRs (<1 to >100 Gyr‑1); (2) 18% are quiescent/dormant (i.e., subject to reignition/rejuvenation) galaxies (QGs) at 3 < z < 5, with and poststarburst mass-weighted ages (0.5–1.0 Gyr); and (3) 11% are strong young starbursts with indications of high equivalent width emission lines (typically, [O III]+Hβ) at 6 < z < 7 (XELG-z6) and . The sample is dominated by disk-like galaxies with remarkable compactness for XELG-z6 (effective radii smaller than 0.4 kpc). Large attenuations in SFGs, 2 < A(V) < 5 mag, are found within 1.5 times the effective radius, approximately 2 kpc, while QGs present A(V) ∼ 0.2 mag. Our SED-fitting technique reproduces the expected dust emission luminosities of IR-bright and submillimeter galaxies. This study implies high levels of star formation activity between z ∼ 20 and z ∼ 10, where virtually 100% of our galaxies had already formed 108 M ⊙, 60% had assembled 109 M ⊙, and 10% up to 1010 M ⊙ (in situ or ex situ).