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EPOCHS VI: The Size and Shape Evolution of Galaxies since z ∼ 8 with JWST Observations

Ormerod, K, Conselice, CJ, Adams, NJ, Harvey, T, Austin, D, Trussler, J, Ferreira, L, Caruana, J, Lucatelli, G, Li, Q and Roper, WJ (2023) EPOCHS VI: The Size and Shape Evolution of Galaxies since z ∼ 8 with JWST Observations. Monthly Notices of the Royal Astronomical Society, 527 (3). pp. 6110-6125. ISSN 0035-8711

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We present the results of a size and structural analysis of 1395 galaxies at 0.5 ≤ z ≲ 8 with stellar masses log (M*/M⊙> 9.5 within the JWST Public CEERS field that overlaps with the HST CANDELS EGS observations. We use GALFIT to fit single Sérsic models to the rest-frame optical profile of our galaxies, which is a mass-selected sample complete to our redshift and mass limit. Our primary result is that at fixed rest-frame wavelength and stellar mass, galaxies get progressively smaller, evolving as ∼(1 + z)−0.71 ± 0.19 up to z ∼ 8. We discover that the vast majority of massive galaxies at high redshifts have low Sérsic indices, thus do not contain steep, concentrated light profiles. Additionally, we explore the evolution of the size-stellar mass relationship, finding a correlation such that more massive systems are larger up to z ∼ 3. This relationship breaks down at z > 3, where we find that galaxies are of similar sizes, regardless of their star formation rates and Sérsic index, varying little with mass. We show that galaxies are more compact at redder wavelengths, independent of sSFR or stellar mass up to z ∼ 3. We demonstrate the size evolution of galaxies continues up to z ∼ 8, showing that the process or causes for this evolution is active at early times. We discuss these results in terms of ideas behind galaxy formation and evolution at early epochs, such as their importance in tracing processes driving size evolution, including minor mergers and AGN activity.

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: Oxford University Press (OUP)
SWORD Depositor: A Symplectic
Date Deposited: 28 Nov 2023 14:10
Last Modified: 09 Jan 2024 13:45
DOI or ID number: 10.1093/mnras/stad3597
URI: https://researchonline.ljmu.ac.uk/id/eprint/21965
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