Early Results from GLASS-JWST. V: The First Rest-frame Optical Size-Luminosity Relation of Galaxies at z > 7

Journal
Date Issued
2022
Author(s)
Yang, L.
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Morishita, T.
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Leethochawalit, N.
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•
Calabrò, A.
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Treu, T.
•
•
•
Mason, C.
•
•
•
Trenti, M.
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Roberts-Borsani, G.
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Bradac, M.
•
•
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Marchesini, D.
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Ding, X.
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Nanayakkara, T.
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Birrer, S.
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Glazebrook, K.
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Jones, T.
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Boyett, K.
•
•
Strait, V.
•
Wang, X.
DOI
Abstract
We present the first rest-frame optical size-luminosity relation of galaxies at z > 7, using the NIRCam imaging data obtained by the GLASS James Webb Space Telescope Early Release Science (GLASS-JWST-ERS) program, providing the deepest extragalactic data of the ERS campaign. Our sample consists of 19 photometrically selected bright galaxies with m F444W ≤ 27.8 at 7 < z < 9 and m F444W < 28.2 at z ~ 9-15. We measure the size of the galaxies in five bands, from rest-frame optical (~4800 Å) to the UV (~1600 Å) based on the Sérsic model, and analyse the size-luminosity relation as a function of wavelength. Remarkably, the data quality of the NIRCam imaging is sufficient to probe the half-light radius r e down to ~100 pc at z > 7. Given the limited sample size and magnitude range, we first fix the slope to that observed for larger samples in rest-frame UV using Hubble Space Telescope samples. The median size r 0 at the reference luminosity M = -21 decreases slightly from rest-frame optical (600 ± 80 pc) to UV (450 ± 130 pc). We then refit the size-luminosity relation allowing the slope to vary. The slope is consistent with β ~ 0.2 for all bands except F150W, where we find a marginally steeper slope of β = 0.53 ± 0.15. The steep UV slope is mainly driven by the smallest and faintest galaxies. If confirmed by larger samples, it implies that the UV size-luminosity relation breaks toward the faint end, as suggested by lensing studies.
Volume
938
Issue
2
Start page
L17
Uri
Url
Issn Identifier
2041-8205
Ads BibCode
2022ApJ...938L..17Y
Rights
open.access
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