Dusty Starbursts Masquerading as Ultra-high Redshift Galaxies in JWST CEERS Observations
Abstract
Lyman Break Galaxy (LBG) candidates at z>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<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 2.6sigma 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.
Keywords
Cite
@article{arxiv.2208.01816,
title = {Dusty Starbursts Masquerading as Ultra-high Redshift Galaxies in JWST CEERS Observations},
author = {Jorge A. Zavala and Veronique Buat and Caitlin M. Casey and Denis Burgarella and Steven L. Finkelstein and Micaela B. Bagley and Laure Ciesla and Emanuele Daddi and Mark Dickinson and Henry C. Ferguson and Maximilien Franco and E. F. Jim'enez-Andrade and Jeyhan S. Kartaltepe and Anton M. Koekemoer and Aurélien Le Bail and E. J. Murphy and Casey Papovich and Sandro Tacchella and Stephen M. Wilkins and Itziar Aretxaga and Peter Behroozi and Jaclyn B. Champagne and Adriano Fontana and Mauro Giavalisco and Andrea Grazian and Norman A. Grogin and Lisa J. Kewley and Dale D. Kocevski and Allison Kirkpatrick and Jennifer M. Lotz and Laura Pentericci and Pablo G. Perez-Gonzalez and Nor Pirzkal and Swara Ravindranath and Rachel S. Somerville and Jonathan R. Trump and Guang Yang and L. Y. Aaron Yung and Omar Almaini and Ricardo O. Amorin and Marianna Annunziatella and Pablo Arrabal Haro and Bren E. Backhaus and Guillermo Barro and Eric F. Bell and Rachana Bhatawdekar and Laura Bisigello and Fernando Buitrago and Antonello Calabro and Marco Castellano and Oscar A. Chavez Ortiz and Katherine Chworowsky and Nikko J. Cleri and Seth H. Cohen and Justin W. Cole and Kevin C. Cooke and M. C. Cooper and Asantha R. Cooray and Luca Costantin and Isabella G. Cox and Darren Croton and Romeel Dave and Alexander de la Vega and Avishai Dekel and David Elbaz and Vicente Estrada-Carpenter and Vital Fernández and Keely D. Finkelstein and Jonathan Freundlich and Seiji Fujimoto and Ángela García-Argumánez and Jonathan P. Gardner and Eric Gawiser and Carlos Gómez-Guijarro and Yuchen Guo and Timothy S. Hamilton and Nimish P. Hathi and Benne W. Holwerda and Michaela Hirschmann and Marc Huertas-Company and Taylor A. Hutchison and Kartheik G. Iyer and Anne E. Jaskot and Saurabh W. Jha and Shardha Jogee and Stéphanie Juneau and Intae Jung and Susan A. Kassin and Peter Kurczynski and Rebecca L. Larson and Gene C. K. Leung and Arianna Long and Ray A. Lucas and Benjamin Magnelli and Kameswara Bharadwaj Mantha and Jasleen Matharu and Elizabeth J. McGrath and Daniel H. McIntosh and Aubrey Medrano and Emiliano Merlin and Bahram Mobasher and Alexa M. Morales and Jeffrey A. Newman and David C. Nicholls and Viraj Pandya and Marc Rafelski and Kaila Ronayne and Caitlin Rose and Russell E. Ryan and Paola Santini and Lise-Marie Seillé and Ekta A. Shah and Lu Shen and Raymond C. Simons and Gregory F. Snyder and Elizabeth R. Stanway and Amber N. Straughn and Harry I. Teplitz and Brittany N. Vanderhoof and Jesús Vega-Ferrero and Weichen Wang and Benjamin J. Weiner and Christopher N. A. Willmer and Stijn Wuyts},
journal= {arXiv preprint arXiv:2208.01816},
year = {2023}
}
Comments
Published in The Astrophysical Journal Letters (updated to match the published version)