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Unveiling the Distant Universe: Characterizing z ≥ 9 Galaxies in the First Epoch of COSMOS-Web

Franco, Maximilien; Akins, Hollis B.; Casey, Caitlin M.; Finkelstein, Steven L.; Shuntov, Marko; Chworowsky, Katherine; Faisst, Andreas L.; Fujimoto, Seiji; Ilbert, Olivier; Koekemoer, Anton M.; Liu, Daizhong; Lovell, Christopher C.; Maraston, Claudia; McCracken, Henry Joy; McKinney, Jed; Robertson, Brant E.; Bagley, Micaela B.; Champagne, Jaclyn B.; Cooper, Olivia R.; Ding, Xuheng; Drakos, Nicole E.; Enia, Andrea; Gillman, Steven; Gozaliasl, Ghassem; Harish, Santosh; Hayward, Christopher C.; Hirschmann, Michaela; Jin, Shuowen; Kartaltepe, Jeyhan S.; Kokorev, Vasily; Laigle, Clotilde; Long, Arianna S.; Magdis, Georgios; Mahler, Guillaume; Martin, Crystal L.; Massey, Richard; Mobasher, Bahram; Paquereau, Louise; Renzini, Alvio; Rhodes, Jason; Rich, R. Michael; Sheth, Kartik; Silverman, John D.; Sparre, Martin; Talia, Margherita; Trakhtenbrot, Benny; Valentino, Francesco; Vijayan, Aswin P.; Wilkins, Stephen M.; Yang, Lilan; Zavala, Jorge A.

Unveiling the Distant Universe: Characterizing z ≥ 9 Galaxies in the First Epoch of COSMOS-Web Thumbnail


Authors

Maximilien Franco

Hollis B. Akins

Caitlin M. Casey

Steven L. Finkelstein

Marko Shuntov

Katherine Chworowsky

Andreas L. Faisst

Seiji Fujimoto

Olivier Ilbert

Anton M. Koekemoer

Daizhong Liu

Christopher C. Lovell

Claudia Maraston

Henry Joy McCracken

Jed McKinney

Brant E. Robertson

Micaela B. Bagley

Jaclyn B. Champagne

Olivia R. Cooper

Xuheng Ding

Nicole E. Drakos

Andrea Enia

Steven Gillman

Ghassem Gozaliasl

Santosh Harish

Christopher C. Hayward

Michaela Hirschmann

Shuowen Jin

Jeyhan S. Kartaltepe

Vasily Kokorev

Clotilde Laigle

Arianna S. Long

Georgios Magdis

Crystal L. Martin

Bahram Mobasher

Louise Paquereau

Alvio Renzini

Jason Rhodes

R. Michael Rich

Kartik Sheth

John D. Silverman

Martin Sparre

Margherita Talia

Benny Trakhtenbrot

Francesco Valentino

Aswin P. Vijayan

Stephen M. Wilkins

Lilan Yang

Jorge A. Zavala



Abstract

We report the identification of 15 galaxy candidates at z ≥ 9 using the initial COSMOS-Web JWST observations over 77 arcmin2 through four Near Infrared Camera filters (F115W, F150W, F277W, and F444W) with an overlap with the Mid-Infrared Imager (F770W) of 8.7 arcmin2. We fit the sample using several publicly available spectral energy distribution (SED) fitting and photometric redshift codes and determine their redshifts between z = 9.3 and z = 10.9 (〈z〉 = 10.0), UV magnitudes between M UV = −21.2 and −19.5 (with 〈M UV〉 = −20.2), and rest-frame UV slopes (〈β〉 = −2.4). These galaxies are, on average, more luminous than most z ≥ 9 candidates discovered by JWST so far in the literature, while exhibiting similar blue colors in their rest-frame UV. The rest-frame UV slopes derived from SED fitting are blue (β ∼ [−2.0, −2.7]) without reaching extremely blue values as reported in other recent studies at these redshifts. The blue color is consistent with models that suggest the underlying stellar population is not yet fully enriched in metals like similarly luminous galaxies in the lower-redshift Universe. The derived stellar masses with 〈log10( M ⋆/M ⊙)〉 ≈ 8–9 are not in tension with the standard Lambda cold dark matter (ΛCDM) model, and our measurement of the volume density of such UV-luminous galaxies aligns well with previously measured values presented in the literature at z ∼ 9–10. Our sample of galaxies, although compact, is significantly resolved.

Citation

Franco, M., Akins, H. B., Casey, C. M., Finkelstein, S. L., Shuntov, M., Chworowsky, K., Faisst, A. L., Fujimoto, S., Ilbert, O., Koekemoer, A. M., Liu, D., Lovell, C. C., Maraston, C., McCracken, H. J., McKinney, J., Robertson, B. E., Bagley, M. B., Champagne, J. B., Cooper, O. R., Ding, X., …Zavala, J. A. (2024). Unveiling the Distant Universe: Characterizing z ≥ 9 Galaxies in the First Epoch of COSMOS-Web. The Astrophysical Journal, 973(1), Article 23. https://doi.org/10.3847/1538-4357/ad5e6a

Journal Article Type Article
Acceptance Date Jul 1, 2024
Online Publication Date Sep 12, 2024
Publication Date Sep 20, 2024
Deposit Date Sep 17, 2024
Publicly Available Date Sep 18, 2024
Journal The Astrophysical Journal
Electronic ISSN 1538-4357
Peer Reviewed Peer Reviewed
Volume 973
Issue 1
Article Number 23
DOI https://doi.org/10.3847/1538-4357/ad5e6a
Keywords Galaxy formation, Early universe, Galaxy evolution, High-redshift galaxies
Public URL https://durham-repository.worktribe.com/output/2864308

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