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Published October 20, 2022 | public
Journal Article

Early Results from GLASS-JWST. III. Galaxy Candidates at z ∼9-15*

Abstract

We present the results of a first search for galaxy candidates at z ∼ 9–15 on deep seven-band NIRCam imaging acquired as part of the GLASS-James Webb Space Telescope (JWST) Early Release Science Program on a flanking field of the Frontier Fields cluster A2744. Candidates are selected via two different renditions of the Lyman-break technique, isolating objects at z ∼ 9–11, and z ∼ 9–15, respectively, supplemented by photometric redshifts obtained with two independent codes. We find five color-selected candidates at z > 9, plus one additional candidate with photometric redshift z_(phot) ≥ 9. In particular, we identify two bright candidates at M_(UV) ≃ −21 that are unambiguously placed at z ≃ 10.6 and z ≃ 12.2, respectively. The total number of galaxies discovered at z > 9 is in line with the predictions of a nonevolving luminosity function. The two bright ones at z > 10 are unexpected given the survey volume, although cosmic variance and small number statistics limits general conclusions. This first search demonstrates the unique power of JWST to discover galaxies at the high-redshift frontier. The candidates are ideal targets for spectroscopic follow-up in Cycle-2.

Additional Information

This work is based on observations made with the NASA/ESA/Canadian Space Agency James Webb Space Telescope. The data were obtained from the Mikulski Archive for Space Telescopes at the Space Telescope Science Institute, which is operated by the Association of Universities for Research in Astronomy, Inc., under NASA contract NAS 5-03127 for JWST. These observations are associated with program JWST-ERS-1324. The JWST data used in this paper can be found on MAST: 10.17909/fqaq-p393. We acknowledge financial support from NASA through grants JWST-ERS-1342. K.G. and T.N. acknowledge support from Australian Research Council Laureate Fellowship FL180100060. C.M. acknowledges support by the VILLUM FONDEN under grant 37459. The Cosmic Dawn Center (DAWN) is funded by the Danish National Research Foundation under grant DNRF140. We acknowledge support from INAF Minigrant "Reionization and fundamental cosmology with high-redshift galaxies." We thank Pascal Oesch and Rohan Naidu for the useful feedback and discussion.

Additional details

Created:
August 22, 2023
Modified:
October 23, 2023