Date: 3/6/2024
Arxiv: JWST PRIMER: A new multi-field determination of the evolving galaxy UV
luminosity function at redshifts \mathbf{z \simeq 9-15}
Published: 3/5/2024 8:06:01 PM
Updated: 3/5/2024 8:06:01 PM
Paper abstract: We present a new determination of the evolving galaxy UV luminosity function(LF) over the redshift range 8.58.5)>0.05) to undertake a statistical calculation of theevolving UV LF. Our new measurements span ~eq4 magnitudes in UV luminosityat z=9-12.5, placing new constraints on both the shape and evolution of theLF at early times. We fit our observational data-points with a double-power law(DPL) function and explore the evolution of the DPL parameters. Our UV LFmeasurements yield a new estimate of the early evolution of cosmicstar-formation rate density (\rho_{\rm{SFR}}) which confirms the gradual,log-linear decline deduced from early JWST studies, at least out to z ~eq12. Finally we show that the observed early evolution of the galaxy UV LF (and\rho_{\rm{SFR}}) can be reproduced in a {\rm \Lambda}CDM Universe, with nochange in dust properties or star-formation efficiency required out to z~eq 12. Instead, we show that a progressive trend towards younger stellarpopulation ages can reproduce the observations, and we show that the typicalages required at z ~eq 8, 9, 10, and 11 all converge on a time ~eq380-330 Myr after the Big Bang, indicative of a rapid emergence of earlygalaxies at z ~eq 12 - 13. This is consistent with the first indicationsof a steeper drop-off in the galaxy population we find beyond z ~eq 13,possibly reflecting the rapid evolution of the halo mass function at earliertimes.
