Dusty Starbursts Masquerading as Ultra-high Redshift Galaxies in JWST CEERS Observations
Creators: name: Zavala, Jorge A.
name: Buat, Veronique
name: Casey, Caitlin M.
name: Burgarella, Denis
name: Finkelstein, Steven L.
name: Bagley, Micaela B.
name: Ciesla, Laure
name: Daddi, Emanuele
name: Dickinson, Mark
name: Ferguson, Henry C.
name: Franco, Maximilien
name: Jim'enez-Andrade, E. F.
name: Kartaltepe, Jeyhan S.
name: Koekemoer, Anton M.
name: Bail, Aurélien Le
name: Murphy, E. J.
name: Papovich, Casey
name: Tacchella, Sandro
name: Wilkins, Stephen M.
name: Aretxaga, Itziar
name: Behroozi, Peter
name: Champagne, Jaclyn B.
name: Fontana, Adriano
name: Giavalisco, Mauro
name: Grazian, Andrea
name: Grogin, Norman A.
name: Kewley, Lisa J.
name: Kocevski, Dale D.
name: Kirkpatrick, Allison
name: Lotz, Jennifer M.
name: Pentericci, Laura
name: Perez-Gonzalez, Pablo G.
name: Pirzkal, Nor
name: Ravindranath, Swara
name: Somerville, Rachel S.
name: Trump, Jonathan R.
name: Yang, Guang
name: Yung, L. Y. Aaron
name: Almaini, Omar
name: Amorin, Ricardo O.
name: Annunziatella, Marianna
name: Haro, Pablo Arrabal
name: Backhaus, Bren E.
name: Barro, Guillermo
name: Bell, Eric F.
name: Bhatawdekar, Rachana
name: Bisigello, Laura
name: Buitrago, Fernando
name: Calabro, Antonello
name: Castellano, Marco
name: Ortiz, Oscar A. Chavez
name: Chworowsky, Katherine
name: Cleri, Nikko J.
name: Cohen, Seth H.
name: Cole, Justin W.
name: Cooke, Kevin C.
name: Cooper, M. C.
name: Cooray, Asantha R.
name: Costantin, Luca
name: Cox, Isabella G.
name: Croton, Darren
name: Dave, Romeel
name: de la Vega, Alexander
name: Dekel, Avishai
name: Elbaz, David
name: Estrada-Carpenter, Vicente
name: Fernández, Vital
name: Finkelstein, Keely D.
name: Freundlich, Jonathan
name: Fujimoto, Seiji
name: García-Argumánez, Ángela
name: Gardner, Jonathan P.
name: Gawiser, Eric
name: Gómez-Guijarro, Carlos
name: Guo, Yuchen
name: Hamilton, Timothy S.
name: Hathi, Nimish P.
name: Holwerda, Benne W.
name: Hirschmann, Michaela
name: Huertas-Company, Marc
name: Hutchison, Taylor A.
name: Iyer, Kartheik G.
name: Jaskot, Anne E.
name: Jha, Saurabh W.
name: Jogee, Shardha
name: Juneau, Stéphanie
name: Jung, Intae
name: Kassin, Susan A.
name: Kurczynski, Peter
name: Larson, Rebecca L.
name: Leung, Gene C. K.
name: Long, Arianna
name: Lucas, Ray A.
name: Magnelli, Benjamin
name: Mantha, Kameswara Bharadwaj
name: Matharu, Jasleen
name: McGrath, Elizabeth J.
name: McIntosh, Daniel H.
name: Medrano, Aubrey
name: Merlin, Emiliano
name: Mobasher, Bahram
name: Morales, Alexa M.
name: Newman, Jeffrey A.
name: Nicholls, David C.
name: Pandya, Viraj
name: Rafelski, Marc
name: Ronayne, Kaila
name: Rose, Caitlin
name: Ryan, Russell E.
name: Santini, Paola
name: Seillé, Lise-Marie
name: Shah, Ekta A.
name: Shen, Lu
name: Simons, Raymond C.
name: Snyder, Gregory F.
name: Stanway, Elizabeth R.
name: Straughn, Amber N.
name: Teplitz, Harry I.
name: Vanderhoof, Brittany N.
name: Vega-Ferrero, Jesús
name: Wang, Weichen
name: Weiner, Benjamin J.
name: Willmer, Christopher N. A.
name: Wuyts, Stijn
Publisher: name: arXiv
Year: 2022
Subjects: subject: Astrophysics of Galaxies (astro-ph.GA)
subject: FOS: Physical sciences
subject: FOS: Physical sciences

description: Lyman Break Galaxy (LBG) candidates at z&gt;10 are rapidly being identified in JWST/NIRCam observations. Due to the (redshifted) break produced by neutral hydrogen absorption of rest-frame UV photons, these sources are expected to drop out in the bluer filters while being well detected in redder filters. However, here we show that dust-enshrouded star-forming galaxies at lower redshifts (z&lt;7) may also mimic the near-infrared (near-IR) colors of z&gt;10 LBGs, representing potential contaminants in LBG candidate samples. First, we analyze CEERS-DSFG-1, a NIRCam dropout undetected in the F115W and F150W filters but detected at longer wavelengths. Combining the JWST data with (sub)millimeter constraints, including deep NOEMA interferometric observations, we show that this source is a dusty star-forming galaxy (DSFG) at z~5.1. We also present a tentative 2.6sigma SCUBA-2 detection at 850um around a recently identified z~16 LBG candidate in the same field and show that, if the emission is real and associated with this candidate, the available photometry is consistent with a z~5 dusty galaxy with strong nebular emission lines despite its blue near-IR colors. Further observations on this candidate are imperative to mitigate the low confidence of this tentative submillimeter emission and its positional uncertainty. Our analysis shows that robust (sub)millimeter detections of NIRCam dropout galaxies likely imply z=4-6 redshift solutions, where the observed near-IR break would be the result of a strong rest-frame optical Balmer break combined with high dust attenuation and strong nebular line emission, rather than the rest-frame UV Lyman break. This provides evidence that DSFGs may contaminate searches for ultra high-redshift LBG candidates from JWST observations.
description: Published in The Astrophysical Journal Letters (updated to match the published version)