Publication Date

2023

Journal or Book Title

Monthly Notices of the Royal Astronomical Society

Abstract

Over the last few years, both Atacama Large Millimeter/submillimeter Array (ALMA) and Spitzer observations have revealed a population of likely massive galaxies at z > 3 that was too faint to be detected inHubble Space Telescope(HST) rest-frame ultraviolet imaging. However, due to the very limited photometry for individual galaxies, the true nature of these so-called HST-dark galaxies has remained elusive. Here, we present the first sample of such galaxies observed with very deep, high-resolution NIRCam imaging from the Early Release Science programme CEERS. 30 HST-dark sources are selected based on their red colours across 1.6–4.4 μ" role="presentation" style="box-sizing: border-box; margin: 0px; padding: 0px; border: 0px; font-variant: inherit; font-stretch: inherit; line-height: normal; font-family: inherit; font-optical-sizing: inherit; font-kerning: inherit; font-feature-settings: inherit; font-variation-settings: inherit; vertical-align: baseline; display: inline; word-spacing: normal; overflow-wrap: normal; text-wrap: nowrap; float: none; direction: ltr; max-width: none; max-height: none; min-width: 0px; min-height: 0px; position: relative;">μ�m. Their physical properties are derived from 12-band multiwavelength photometry, including ancillary HST imaging. We find that these galaxies are generally heavily dust-obscured (AV ∼ 2 mag), massive (log (M/M⊙) ∼ 10), star-forming sources at z ∼ 2−8 with an observed surface density of ∼0.8 arcmin−2. This suggests that an important fraction of massive galaxies may have been missing from our cosmic census at z > 3 all the way into the Epoch of Reionization. The HST-dark sources lie on the main sequence of galaxies and add an obscured star formation rate density of 3.2−1.3+1.8×10−3M⊙yr−1Mpc−3" role="presentation" style="box-sizing: border-box; margin: 0px; padding: 0px; border: 0px; font-variant: inherit; font-stretch: inherit; line-height: normal; font-family: inherit; font-optical-sizing: inherit; font-kerning: inherit; font-feature-settings: inherit; font-variation-settings: inherit; vertical-align: baseline; display: inline; word-spacing: normal; overflow-wrap: normal; text-wrap: nowrap; float: none; direction: ltr; max-width: none; max-height: none; min-width: 0px; min-height: 0px; position: relative;">3.2+1.8−1.3×10−3M⊙yr−1Mpc−33.2−1.3+1.8×10−3M⊙yr−1Mpc−3 at z ∼ 7, showing likely presence of dust in the Epoch of Reionization. Our analysis shows the unique power of JWST to reveal this previously missing galaxy population and to provide a more complete census of galaxies at z = 2−8 based on rest-frame optical imaging.

DOI

https://doi.org/10.1093/mnras/stad947

Volume

522

Issue

1

License

UMass Amherst Open Access Policy

Creative Commons License

Creative Commons Attribution 4.0 License
This work is licensed under a Creative Commons Attribution 4.0 License.

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