Dusty Starbursts Masquerading as Ultra-high Redshift Galaxies in JWST CEERS Observations

Zavala, J. A.; Buat, V.; Casey, C. M.; Finkelstein, S. L.; Burgarella, D.; Bagley, M. B.; Ciesla, L.; Daddi, E.; Dickinson, M.; Ferguson, H. C.; Franco, M.; Jimenez-Andrade, E. F.; Kartaltepe, J. S.; Koekemoer, A. M.; Bail, A. L.; Murphy, E. J.; Papovich, C.; Tacchella, S.; Wilkins, S. M.; Aretxaga, I.; Behroozi, P.; Champagne, J. B.; Fontana, A.; Giavalisco, M.; Grazian, A.; Grogin, N. A.; Kewley, L. J.; Kocevski, D. D.; Kirkpatrick, A.; Lotz, J. M.; Pentericci, L.; Perez-Gonzalez, P. G.; Pirzkal, N.; Ravindranath, S.; Somerville, R. S.; Trump, J. R.; Yang, G.; Aaron Yung, L. Y.; Almaini, O.; Amorin, R. O.; Annunziatella, M.; Haro, P. A.; Backhaus, B. E.; Barro, G.; Bell, E. F.; Bhatawdekar, R.; Bisigello, L.; Buitrago, F.; Calabro, A.; Castellano, M.; Chavez Ortiz, I. A.; Chworowsky, K.; Cleri, N. J.; Cohen, S. H.; Cole, J. W.; Cooke, K. C.; Cooper, M. C.; Cooray, A. R.; Costantin, L.; Cox, I. G.; Croton, D.; Dave, R.; Vega, A. D. L.; Dekel, A.; Elbaz, D.; Estrada-Carpenter, V.; Fernandez, V.; Finkelstein, K. D.; Freundlich, J.; Fujimoto, S.; Garcia-Argumanez, I.; Gardner, J. P.; Gawiser, E.; Gomez-Guijarro, C.; Guo, Y.; Hamilton, T. S.; Hathi, N. P.; Holwerda, B. W.; Hirschmann, M.; Huertas-Company, M.; Hutchison, T. A.; Iyer, K. G.; Jaskot, A. E.; Jha, S. W.; Jogee, S.; Juneau, S.; Jung, I.; Kassin, S. A.; Kurczynski, P.; Larson, R. L.; Leung, G. C. K.; Long, A. S.; Lucas, R. A.; Magnelli, B.; Mantha, K. B.; Matharu, J.; Mcgrath, E. J.; Mcintosh, D. H.; Medrano, A.; Merlin, E.; Mobasher, B.; Morales, A. M.; Newman, J. A.; Nicholls, D. C.; Pandya, V.; Rafelski, M.; Ronayne, K.; Rose, C.; Ryan, R. E.; Santini, P.; Seille, L. -M.; Shah, E. A.; Shen, L.; Simons, R. C.; Snyder, G. F.; Stanway, E. R.; Straughn, A. N.; Teplitz, H. I.; Vanderhoof, B. N.; Vega-Ferrero, J.; Wang, W.; Weiner, B. J.; Willmer, C. N. A.; Wuyts, S.

doi:10.3847/2041-8213/acacfe

Lyman-break galaxy (LBG) candidates at z ≳ 10 are rapidly being identified in James Webb Space Telescope (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 ≲ 7) may also mimic the near-infrared (near-IR) colors of z > 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 2.6σ SCUBA-2 detection at 850 μm around a recently identified z ≈ 16 LBG candidate in the same field and sh...