A Census from JWST of Extreme Emission-line Galaxies Spanning the Epoch of Reionization in CEERS

Authors

• Kelcey Davis, University of Connecticut
• Jonathan R. Trump, University of Connecticut
• Raymond C. Simons, University of Connecticut
• Elizabeth J. McGrath, Colby College
• Stephen M. Wilkins, University of Sussex
• Pablo Arrabal Haro, NOIRLab
• Micaela B. Bagley, The University of Texas at Austin
• Mark Dickinson, NOIRLab
• Vital Fernández, University of Michigan, Ann Arbor
• Ricardo O. Amorín, Consejo Superior de Investigaciones Científicas
• Bren E. Backhaus, University of Connecticut
• Nikko J. Cleri, Pennsylvania State University
• Mario Llerena, Universidad de La Serena
• Samantha W. Brunker, University of Connecticut
• Guillermo Barro, University of the PacificFollow
• Laura Bisigello, Università degli Studi di Padova
• Madisyn Brooks, University of Connecticut
• Luca Costantin, CSIC-INTA - Centro de Astrobiología (CAB)
• Alexander de la Vega, University of California, Riverside
• Avishai Dekel, Hebrew University of Jerusalem
• Steven L. Finkelstein, The University of Texas at Austin

Document Type

Article

Publication Title

Astrophysical Journal

Department

Physics

ISSN

15384357

Volume

974

Issue

1

DOI

10.3847/1538-4357/ad6865

First Page

1

Last Page

21

Publication Date

10-3-2024

Abstract

We present a sample of 1165 extreme emission-line galaxies (EELGs) at 4 < z < 9 selected using James Webb Space Telescope (JWST) NIRCam photometry in the Cosmic Evolution Early Release Science (CEERS) program. We use a simple method to photometrically identify EELGs with Hβ + [O iii] (combined) or Hα emission of observed-frame equivalent width (EW) > 5000 Å. JWST/NIRSpec spectroscopic observations of a subset (34) of the photometrically selected EELGs validate our selection method: All spectroscopically observed EELGs confirm our photometric identification of extreme emission, including some cases where the spectral-energy-distribution-derived photometric redshifts are incorrect. We find that the medium-band F410M filter in CEERS is particularly efficient at identifying EELGs, both in terms of including emission lines in the filter and in correctly identifying the continuum between Hβ + [O iii] and Hα in the neighboring broadband filters. We present examples of EELGs that could be incorrectly classified as ultrahigh redshift (z > 12) as a result of extreme Hβ + [O iii] emission blended across the reddest photometric filters. We compare the EELGs to the broader (subextreme) galaxy population in the same redshift range and find that they are consistent with being the bluer, high-EW tail of a broader population of emission-line galaxies. The highest-EW EELGs tend to have more compact emission-line sizes than continuum sizes, suggesting that active galactic nuclei are responsible for at least some of the most extreme EELGs. The photometrically inferred emission-line ratios are consistent with interstellar medium conditions with high ionization and moderately low metallicity, consistent with previous spectroscopic studies.

Creative Commons License

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

Recommended Citation

Davis, Kelcey; Trump, Jonathan R.; Simons, Raymond C.; McGrath, Elizabeth J.; Wilkins, Stephen M.; Arrabal Haro, Pablo; Bagley, Micaela B.; Dickinson, Mark; Fernández, Vital; Amorín, Ricardo O.; Backhaus, Bren E.; Cleri, Nikko J.; Llerena, Mario; Brunker, Samantha W.; Barro, Guillermo; Bisigello, Laura; Brooks, Madisyn; Costantin, Luca; de la Vega, Alexander; Dekel, Avishai; and Finkelstein, Steven L., "A Census from JWST of Extreme Emission-line Galaxies Spanning the Epoch of Reionization in CEERS" (2024). Pacific Faculty Work. 88.
https://scholarlycommons.pacific.edu/all-faculty/88