# JWST PRIMER: a new multifield determination of the evolving galaxy UV luminosity function at redshifts z ≃ 9 – 15

Article · Callum T. Donnan, R. J. McLure, J. S. Dunlop, Derek J. McLeod, Daniel K. Magee, Karla Z. Arellano-Córdova, Laia Barrufet, R Begley, R. A. A. Bowler, Adam C. Carnall, Fergus Cullen, Richard S. Ellis, A. Fontana, Garth D. Illingworth, Norman A. Grogin, M. L. Hamadouche, Anton M. Koekemoer, Feng-Yuan Frey Liu, Charlotte A. Mason, Paola Santini, T. M. Stanton

- Archive id: doi:10.1093/mnras/stae2037
- Published: 2024-08-24
- Venue: Monthly Notices of the Royal Astronomical Society
- DOI: https://doi.org/10.1093/mnras/stae2037
- Citations: 175
- Source URL: https://doi.org/10.1093/mnras/stae2037
- Provenance: openalex

## Abstract

ABSTRACT We present a new determination of the evolving galaxy ultraviolet (UV) luminosity function (LF) over the redshift range $8.5\< z\< 15.5$ using a combination of several major Cycle-1 JWST imaging programmes – Public Release IMaging for Extragalactic Research, JWST Advanced Deep Extragalactic Survey, and Next Generation Deep Extragalactic Exploratory Public Survey. This multifield approach yields a total of $\\simeq 370$ arcmin2 of JWST/NIRCam imaging, reaching (5-$\\sigma$) depths of $\\simeq 30$ AB mag in the deepest regions. We select a sample of 2548 galaxies with a significant probability of lying at high redshift ($p(z\> 8.5)\> 0.05$) to undertake a statistical calculation of the UV LF. Our new measurements span $\\simeq 4$ mag in UV luminosity at $z=9-12.5$, placing new constraints on both the shape and evolution of the LF at early times. Our measurements yield a new estimate of the early evolution of cosmic star-formation rate density ($\\rho \_{\\rm {SFR}}$) confirming the gradual decline deduced from early JWST studies, at least out to $z \\simeq 12$. Finally we show that the observed early evolution of the galaxy UV LF (and $\\rho \_{\\rm {SFR}}$) can be reproduced in a ${\\rm \\Lambda }$cold dark matter Universe, with no change in dust properties or star-formation efficiency required out to $z \\simeq 12$. Instead, a progressive trend towards younger stellar population ages can reproduce the observations, and the typical ages required at $z \\simeq$ 8, 9, 10, and 11 all converge on $\\simeq 380-330$ Myr after the big bang, indicative of a rapid emergence of early galaxies at $z \\simeq 12 - 13$. This is consistent with the first indications of a steeper drop-off in $\\rho \_{\\rm {SFR}}$ we find beyond $z \\simeq 13$, possibly reflecting the rapid evolution of the halo mass function at earlier times.

_Abstract reproduced under CC-BY (publisher license, via OpenAlex)._

Topics: [JWST & the Early Universe](https://space-kitty.com/topics/early-universe-jwst)

Cited in dossiers:
- [JWST & the Early Universe: State of the Field (October 2026)](https://space-kitty.com/dossiers/early-universe-jwst)

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