A Glimpse of the New Redshift Frontier through AS1063

Abstract We report the discovery of two galaxy candidates at redshifts between 15.7 &lt; z &lt; 16.4 in James Webb Space Telescope (JWST) observations from the GLIMPSE survey. These robust sources were identified using a combination of Lyman break selection and photometric redshift estimates. The ultradeep NIRCam imaging from GLIMPSE, combined with the strong gravitational lensing of the AS1063 galaxy cluster, allows us to probe an intrinsically fainter population (down to M UV = −17.0 mag) than previously achievable. These galaxies have absolute magnitudes ranging from M UV = −17.0 to −17.2 mag, with blue ( β ≃ −2.87) ultraviolet (UV) continuum slopes, consistent with young, dust-free stellar populations. The number density of these objects, log 10 ( ϕ /[Mpc −3 mag −1 ]) = <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:mo>−</mml:mo> <mml:mn>3.4</mml:mn> <mml:msubsup> <mml:mrow> <mml:mn>7</mml:mn> </mml:mrow> <mml:mrow> <mml:mo>−</mml:mo> <mml:mn>0.10</mml:mn> </mml:mrow> <mml:mrow> <mml:mo>+</mml:mo> <mml:mn>0.13</mml:mn> </mml:mrow> </mml:msubsup> </mml:math> at M UV = −17, is in clear tension with pre-JWST theoretical predictions, extending the overabundance of galaxies from z ∼ 10 to z ∼ 17. These results, together with the scarcity of brighter galaxies in other public surveys, suggest a steep decline in the bright end of the UV luminosity function at z ∼ 16, implying efficient star formation and possibly a close connection to the halo mass function at these redshifts. Testing a variety of star formation histories suggests that these sources are plausible progenitors of the unusually UV-bright galaxies that JWST now routinely uncovers at z = 10–14. Overall, our results indicate that the luminosity distribution of the earliest star-forming galaxies could be shifting toward fainter luminosities, implying that future surveys of cosmic dawn will need to explore this faint luminosity regime.

Authors

Institutions

Publication Details

Journal
The Astrophysical Journal Letters
Published
2025-04-08
DOI
https://doi.org/10.3847/2041-8213/adc458
Citations
15
Primary Topic
Galaxies: Formation, Evolution, Phenomena
Type
article
Field-Weighted Citation Impact
16.17

Funders

Controls
|||
ALL TIME
JAN
FEB
MAR
APR
MAY
JUN
JUL
AUG
SEP
OCT
article

A Glimpse of the New Redshift Frontier through AS1063

Seiji Fujimoto, Damien Korber, R. Marques-Chaves, Priyamvada Natarajan et al.
15 citations
The Astrophysical Journal Letters
Galaxies: Formation, Evolution, Phenomena
16.17
article

A Glimpse of the New Redshift Frontier through AS1063

Seiji Fujimoto, Damien Korber, R. Marques-Chaves, Priyamvada Natarajan, Lukas J. Furtak, Jérémy Blaizot, Gourav Khullar, Vasily Kokorev, Danielle A. Berg, Charlotte Mason, R. J. Bouwens, Richard Pan, Kristen B. W. McQuinn, Julián B. Muñoz, Rohan P. Naidu, Ivo Labbé, Angela Adamo, M. Dessauges‐Zavadsky, Joakim Rosdahl, Alberto Saldana-Lopez, D. Schaerer, Iryna Chemerynska, Hakim Atek, Maxime Trebitsch, Erica J. Nelson, Pascal A. Oesch, Adi Zitrin, Ryan Endsley, John Chisholm, Andrea Weibel, Marta Volonteri, Floriane Leclercq, Ilias Goovaerts, Michelle Jecmen
article en
15 citations

Abstract

Abstract We report the discovery of two galaxy candidates at redshifts between 15.7 &lt; z &lt; 16.4 in James Webb Space Telescope (JWST) observations from the GLIMPSE survey. These robust sources were identified using a combination of Lyman break selection and photometric redshift estimates. The ultradeep NIRCam imaging from GLIMPSE, combined with the strong gravitational lensing of the AS1063 galaxy cluster, allows us to probe an intrinsically fainter population (down to M UV = −17.0 mag) than previously achievable. These galaxies have absolute magnitudes ranging from M UV = −17.0 to −17.2 mag, with blue ( β ≃ −2.87) ultraviolet (UV) continuum slopes, consistent with young, dust-free stellar populations. The number density of these objects, log 10 ( ϕ /[Mpc −3 mag −1 ]) = <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:mo>−</mml:mo> <mml:mn>3.4</mml:mn> <mml:msubsup> <mml:mrow> <mml:mn>7</mml:mn> </mml:mrow> <mml:mrow> <mml:mo>−</mml:mo> <mml:mn>0.10</mml:mn> </mml:mrow> <mml:mrow> <mml:mo>+</mml:mo> <mml:mn>0.13</mml:mn> </mml:mrow> </mml:msubsup> </mml:math> at M UV = −17, is in clear tension with pre-JWST theoretical predictions, extending the overabundance of galaxies from z ∼ 10 to z ∼ 17. These results, together with the scarcity of brighter galaxies in other public surveys, suggest a steep decline in the bright end of the UV luminosity function at z ∼ 16, implying efficient star formation and possibly a close connection to the halo mass function at these redshifts. Testing a variety of star formation histories suggests that these sources are plausible progenitors of the unusually UV-bright galaxies that JWST now routinely uncovers at z = 10–14. Overall, our results indicate that the luminosity distribution of the earliest star-forming galaxies could be shifting toward fainter luminosities, implying that future surveys of cosmic dawn will need to explore this faint luminosity regime.

The Astrophysical Journal LettersVol. 983(1)
Damien Foundation (BD)
National Science Foundation, National Aeronautics and Space Administration, John Templeton Foundation, Gordon and Betty Moore Foundation, Harvard University, Space Telescope Science Institute, National Research Foundation, Schweizerischer Nationalfonds zur Förderung der Wissenschaftlichen Forschung, Danmarks Grundforskningsfond, United States-Israel Binational Science Foundation, Centre National d’Etudes Spatiales, Israel Science Foundation, Knut och Alice Wallenbergs Stiftelse, Vetenskapsrådet, Centre National de la Recherche Scientifique, Staatssekretariat für Bildung, Forschung und Innovation, Institut National de Physique Nucléaire et de Physique des Particules
Openalex Percentile: Top 1%
Galaxies: Formation, Evolution, Phenomena
16.17
DOIOpen Access PDFOpenAlex
AI Navigator

Ask Laika to Summarize, Analyze, and Connect papers live on the map.

Summarize Papers & Methodologies

Extract key findings, datasets, and comparative methods across publications.

Benchmark Rankings & Visual Analytics

Rank top research institutions, authors, funders, topics, and journals by Field-Weighted Citation Impact (FWCI) and paper volume with instant charts.

Connect Distant Disciplines

Bridge topological clusters on the map to find hidden collaborative intersections.