1. JWST PRIMER: a new multifield determination of the evolving galaxy UV luminosity function at redshifts z ≃ 9 – 15.
- Author
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Donnan, C T, McLure, R J, Dunlop, J S, McLeod, D J, Magee, D, Arellano-Córdova, K Z, Barrufet, L, Begley, R, Bowler, R A A, Carnall, A C, Cullen, F, Ellis, R S, Fontana, A, Illingworth, G D, Grogin, N A, Hamadouche, M L, Koekemoer, A M, Liu, F -Y, Mason, C, and Santini, P
- Subjects
GALACTIC evolution ,DARK matter ,GALAXY formation ,GALACTIC redshift ,STELLAR populations - 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 |$\simeq 370$| arcmin
2 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 FROM AUTHOR]- Published
- 2024
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