학술논문
Two Massive, Compact, and Dust-obscured Candidate z ≃ 8 Galaxies Discovered by JWST
Document Type
article
Author
Hollis B. Akins; Caitlin M. Casey; Natalie Allen; Micaela B. Bagley; Mark Dickinson; Steven L. Finkelstein; Maximilien Franco; Santosh Harish; Pablo Arrabal Haro; Olivier Ilbert; Jeyhan S. Kartaltepe; Anton M. Koekemoer; Daizhong Liu; Arianna S. Long; Henry Joy McCracken; Louise Paquereau; Casey Papovich; Nor Pirzkal; Jason Rhodes; Brant E. Robertson; Marko Shuntov; Sune Toft; Guang Yang; Guillermo Barro; Laura Bisigello; Véronique Buat; Jaclyn B. Champagne; Olivia Cooper; Luca Costantin; Alexander de la Vega; Nicole E. Drakos; Andreas Faisst; Adriano Fontana; Seiji Fujimoto; Steven Gillman; Carlos Gómez-Guijarro; Ghassem Gozaliasl; Nimish P. Hathi; Christopher C. Hayward; Michaela Hirschmann; Benne W. Holwerda; Shuowen Jin; Dale D. Kocevski; Vasily Kokorev; Erini Lambrides; Ray A. Lucas; Georgios E. Magdis; Benjamin Magnelli; Jed McKinney; Bahram Mobasher; Pablo G. Pérez-González; R. Michael Rich; Lise-Marie Seillé; Margherita Talia; C. Megan Urry; Francesco Valentino; Katherine E. Whitaker; L. Y. Aaron Yung; Jorge Zavala; the COSMOS-Web and CEERS teams
Source
The Astrophysical Journal, Vol 956, Iss 1, p 61 (2023)
Subject
Language
English
ISSN
1538-4357
Abstract
We present a search for extremely red, dust-obscured, z > 7 galaxies with JWST/NIRCam+MIRI imaging over the first 20 arcmin ^2 of publicly available Cycle 1 data from the COSMOS-Web, CEERS, and PRIMER surveys. Based on their red color in F277W−F444W (∼2.5 mag) and detection in MIRI/F770W (∼25 mag), we identify two galaxies, COS-z8M1 and CEERS-z7M1, that have best-fit photometric redshifts of $z={8.4}_{-0.4}^{+0.3}$ and ${7.6}_{-0.1}^{+0.1}$ , respectively. We perform spectral energy distribution fitting with a variety of codes (including bagpipes , prospector , beagle , and cigale ) and find a >95% probability that these indeed lie at z > 7. Both sources are compact ( R _eff ≲ 200 pc) and highly obscured ( A _V ∼ 1.5–2.5) and, at our best-fit redshift estimates, likely have strong [O iii ]+H β emission contributing to their 4.4 μ m photometry. We estimate stellar masses of ∼10 ^10 M _⊙ for both sources; by virtue of detection in MIRI at 7.7 μ m, these measurements are robust to the inclusion of bright emission lines, for example, from an active galactic nucleus. We identify a marginal (2.9 σ ) Atacama Large Millimeter/submillimeter Array detection at 2 mm within 0.″5 of COS-z8M1, which, if real, would suggest a remarkably high IR luminosity of ∼10 ^12 L _⊙ . These two galaxies, if confirmed at z ∼ 8, would be extreme in their stellar and dust masses and may be representative of a substantial population of highly dust-obscured galaxies at cosmic dawn.