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The $z \gtrsim 9$ galaxy UV luminosity function from the JWST Advanced Deep Extragalactic Survey: insights into early galaxy evolution and reionization

Authors :
Whitler, Lily
Stark, Daniel P.
Topping, Michael W.
Robertson, Brant
Rieke, Marcia
Hainline, Kevin N.
Endsley, Ryan
Chen, Zuyi
Baker, William M.
Bhatawdekar, Rachana
Bunker, Andrew J.
Carniani, Stefano
Charlot, Stéphane
Chevallard, Jacopo
Curtis-Lake, Emma
Egami, Eiichi
Eisenstein, Daniel J.
Helton, Jakob M.
Ji, Zhiyuan
Johnson, Benjamin D.
Pérez-González, Pablo G.
Rinaldi, Pierluigi
Tacchella, Sandro
Williams, Christina C.
Willmer, Christopher N. A.
Willott, Chris
Witstok, Joris
Publication Year :
2025

Abstract

The high-redshift UV luminosity function provides important insights into the evolution of early galaxies. JWST has revealed an unexpectedly large population of bright ($M_\mathrm{UV} \lesssim -20$) galaxies at $z\gtrsim10$, implying fundamental changes in the star forming properties of galaxies at increasingly early times. However, constraining the fainter population ($M_\mathrm{UV} \gtrsim -18$) has been more challenging. In this work, we present the $z\gtrsim9$ UV luminosity function from the JWST Advanced Deep Extragalactic Survey. We calculate the UV luminosity function from several hundred $z\gtrsim9$ galaxy candidates that reach UV luminosities of $M_\mathrm{UV}\sim-17$ in redshift bins of $z\sim9-12$ (309 candidates) and $z\sim12-16$ (63 candidates). We search for candidates at $z\sim16-22.5$ and find none. We also estimate the $z\sim14-16$ luminosity function from the $z\geq14$ subset of the $z\sim12-16$ sample. Consistent with other measurements, we find an excess of bright galaxies that is in tension with many theoretical models, especially at $z\gtrsim12$. However, we also find high number densities at $-18\lesssim M_\mathrm{UV} \lesssim-17$, suggesting that there is a larger population of faint galaxies than expected, as well as bright ones. From our parametric fits for the luminosity function, we find steep faint end slopes of $-2.5\lesssim\alpha\lesssim-2.3$, suggesting a large population of faint ($M_\mathrm{UV} \gtrsim -17$) galaxies. Combined, the high normalization and steep faint end slope of the luminosity function could imply that the reionization process is appreciably underway as early as $z=10$.<br />Comment: 32 pages (27 pages of main text), 12 figures, 6 tables

Details

Database :
arXiv
Publication Type :
Report
Accession number :
edsarx.2501.00984
Document Type :
Working Paper