In:
The Astrophysical Journal, American Astronomical Society, Vol. 956, No. 1 ( 2023-10-01), p. 61-
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.
Type of Medium:
Online Resource
ISSN:
0004-637X
,
1538-4357
DOI:
10.3847/1538-4357/acef21
Language:
Unknown
Publisher:
American Astronomical Society
Publication Date:
2023
detail.hit.zdb_id:
2207648-7
detail.hit.zdb_id:
1473835-1
SSG:
16,12