The Rise of the Galactic Empire: Ultraviolet Luminosity Functions at <i>z</i> ∼ 17 and <i>z</i> ∼ 25 Estimated with the MIDIS+NGDEEP Ultra-deep JWST/NIRCam Data Set

Abstract We present a sample of six F200W and three F277W dropout sources identified as 16 &lt; z &lt; 25 galaxy candidates using the deepest JWST/NIRCam data to date (5 σ depths ∼31.5 mag at ≥2 μ m), provided by the MIRI Deep Imaging Survey and the Next Generation Deep Extragalactic Exploratory Public survey. We estimate ultraviolet (UV) luminosity functions and densities at z ∼ 17 and z ∼ 25. The number density of galaxies with absolute magnitudes of −19 &lt; M UV &lt; −18 at z ∼ 17 ( z ∼ 25) is a factor of 4 (25) smaller than at z ∼ 12; the luminosity density presents a similar evolution. Compared to state-of-the-art galaxy simulations, we find the need for an enhanced UV-photon production at z = 17–25 in M DM = 10 8.5−9.5 M ⊙ dark matter halos, provided by an increase in the star formation efficiency at early times and/or by intense compact starbursts with enhanced emissivity linked to strong burstiness, low or primordial gas metallicities, and/or a top-heavy initial mass function. There are a few robust theoretical predictions for the evolution of galaxies above z ∼ 20 in the literature; however, the continuing rapid drop in the halo mass function would predict a more rapid evolution than we observe if photon production efficiencies remained constant. Our z &gt; 16 candidates present mass-weighted ages around 30 Myr, and attenuations A ( V ) &lt; 0.1 mag. Their average stellar mass is M ⋆ ∼ 10 7 M ⊙ , implying a stellar-to-baryon mass fraction around 10% if the emissivity increases with redshift, or significantly higher otherwise. Three candidates present very blue UV spectral slopes ( β ∼ −3) compatible with Population III young (≲10 Myr) stars and/or high escape fractions of ionizing photons; the rest have β ∼ −2.5 similar to the z = 10–12 samples.

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Publication Details

Journal
The Astrophysical Journal
Published
2025-09-26
DOI
https://doi.org/10.3847/1538-4357/adf8c9
Citations
16
Primary Topic
Galaxies: Formation, Evolution, Phenomena
Type
article
Field-Weighted Citation Impact
18.48

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article

The Rise of the Galactic Empire: Ultraviolet Luminosity Functions at z ∼ 17 and z ∼ 25 Estimated with the MIDIS+NGDEEP Ultra-deep JWST/NIRCam Data Set

J. Hjorth, Mauro Giavalisco, K. I. Caputi, Fabian Walter et al.
16 citations
The Astrophysical Journal
Galaxies: Formation, Evolution, Phenomena
18.48
article

The Rise of the Galactic Empire: Ultraviolet Luminosity Functions at z ∼ 17 and z ∼ 25 Estimated with the MIDIS+NGDEEP Ultra-deep JWST/NIRCam Data Set

J. Hjorth, Mauro Giavalisco, K. I. Caputi, Fabian Walter, T. R. Greve, Priyamvada Natarajan, Avishai Dekel, L. Pentericci, D. Burgarella, Vasily Kokorev, Alvaro Labiano, Nimish P. Hathi, Luca Costantin, L. Colina, Gene C. K. Leung, Göran Östlin, Rachel S. Somerville, Casey Papovich, Henry C. Ferguson, Anton M. Koekemoer, Pablo G. Pérez‐González, A. Eckart, Marianna Annunziatella, Leindert Boogaard, Antonello Calabrò, L. Y. Aaron Yung, Pierluigi Rinaldi, Javier Álvarez-Márquez, Nor Pirzkal, P. van der Werf, Steven L. Finkelstein, Mark Dickinson, Jens Melinder, Micaela B. Bagley, Zhaozhou Li, Steven Gillman, M. Hamed, Danial Langeroodi, Jeyhan S. Kartaltepe, Florian Peißker, Y. Cheng
article en
16 citations

Abstract

Abstract We present a sample of six F200W and three F277W dropout sources identified as 16 &lt; z &lt; 25 galaxy candidates using the deepest JWST/NIRCam data to date (5 σ depths ∼31.5 mag at ≥2 μ m), provided by the MIRI Deep Imaging Survey and the Next Generation Deep Extragalactic Exploratory Public survey. We estimate ultraviolet (UV) luminosity functions and densities at z ∼ 17 and z ∼ 25. The number density of galaxies with absolute magnitudes of −19 &lt; M UV &lt; −18 at z ∼ 17 ( z ∼ 25) is a factor of 4 (25) smaller than at z ∼ 12; the luminosity density presents a similar evolution. Compared to state-of-the-art galaxy simulations, we find the need for an enhanced UV-photon production at z = 17–25 in M DM = 10 8.5−9.5 M ⊙ dark matter halos, provided by an increase in the star formation efficiency at early times and/or by intense compact starbursts with enhanced emissivity linked to strong burstiness, low or primordial gas metallicities, and/or a top-heavy initial mass function. There are a few robust theoretical predictions for the evolution of galaxies above z ∼ 20 in the literature; however, the continuing rapid drop in the halo mass function would predict a more rapid evolution than we observe if photon production efficiencies remained constant. Our z &gt; 16 candidates present mass-weighted ages around 30 Myr, and attenuations A ( V ) &lt; 0.1 mag. Their average stellar mass is M ⋆ ∼ 10 7 M ⊙ , implying a stellar-to-baryon mass fraction around 10% if the emissivity increases with redshift, or significantly higher otherwise. Three candidates present very blue UV spectral slopes ( β ∼ −3) compatible with Population III young (≲10 Myr) stars and/or high escape fractions of ionizing photons; the rest have β ∼ −2.5 similar to the z = 10–12 samples.

The Astrophysical JournalVol. 991(2)
Observatoire de Paris (FR), European Space Agency (FR), Laboratoire d’Astrophysique de Marseille (FR), Château Gombert (FR)
National Aeronautics and Space Administration, John Templeton Foundation, Gordon and Betty Moore Foundation, Harvard University, Villum Fonden, Space Telescope Science Institute, Flatiron Health, National Research Foundation, Danmarks Grundforskningsfond, Swedish National Space Agency, Nederlandse Organisatie voor Wetenschappelijk Onderzoek, Vetenskapsrådet, Ministerio de Ciencia e Innovación, Fundación Bancaria Caixa d'Estalvis i Pensions de Barcelona, European Regional Development Fund, Agencia Estatal de Investigación
Openalex Percentile: Top 1%
Galaxies: Formation, Evolution, Phenomena
18.48
DOIOpen Access PDFOpenAlex
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