Austin, D, Adams, N, Conselice, CJ, Harvey, T, Ormerod, K, Trussler, J, Li, Q, Ferreira, L, Dayal, P and Juodžbalis, I (2023) A Large Population of Faint 8<z<16 Galaxies Found in the First JWST NIRCam Observations of the NGDEEP Survey. Astrophysical Journal Letters, 952 (1). ISSN 2041-8205

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Abstract

We present an early analysis on the search for high-redshift galaxies using the deepest public JWST imaging to date, the NGDEEP field. These data consist of six-band NIRCam imaging on the Hubble Ultra Deep Field Parallel 2 (HUDF-Par2), covering a total area of 6.3 arcmin2. Based on our initial reduction of the first half of this survey, we reach 5σ depths up to mag = 29.5-29.9 between 1 and 5 μm. Such depths present an unprecedented opportunity to begin exploring the very early universe with JWST. As such, we find high-redshift galaxies by examining the spectral energy distribution of all F444W detections and present 16 new z > 8.5 galaxies identified using two different photometric redshift codes: LePhare and EAZY combined with other significance criteria. The highest-redshift object in our sample is at z = 15.6 − 0.3 + 0.4 , which has a blue β = − 3.02 − 0.46 + 0.42 and a very low inferred stellar mass of M * = 107.4 M ⊙. We also discover a series of faint, low-mass dwarf galaxies with M * < 108.5 M ⊙ at z ∼ 9 that have blue colors, flat surface brightness profiles, and small sizes <1 kpc. Comparing to previous work in the HUDF-Par2, we find 21 6 < z < 9 candidates including two z = 8 major mergers. One of these merger candidates has an additional two z = 8 sources within 30″, indicating that it may form part of an overdensity. We also compare our results to theory, finding no significant disagreement with a few cold-dark-matter-based models. The discovery of these objects demonstrates the critical need for deeper, or similar depth but wider-area, JWST surveys to explore the early universe.

Item Type:	Article
Uncontrolled Keywords:	0201 Astronomical and Space Sciences; Astronomy & Astrophysics
Subjects:	Q Science > QB Astronomy Q Science > QC Physics
Divisions:	Astrophysics Research Institute
Publisher:	American Astronomical Society
SWORD Depositor:	A Symplectic
Date Deposited:	23 Sep 2024 14:29
Last Modified:	23 Sep 2024 14:30
DOI or ID number:	10.3847/2041-8213/ace18d
URI:	https://researchonline.ljmu.ac.uk/id/eprint/24231

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