The ALMA REBELS Survey: The [C II] Luminosity Function of UV-Selected Galaxies at z∼7
Abstract
Luminosity functions (LF) are some of the most basic quantities providing insights into galaxy evolution across cosmic time and enabling a direct comparison between observations and simulations. Here, we present the first [CII]158μm LF at z∼7 from a sizeable UV-selected ALMA sample. Our analysis makes use of 27 galaxies with significant [CII] emission line detections in the epoch of reionization from the REBELS (Reionization Era Bright Emission Line Survey) ALMA Large Program and its pilot programs. We used these line detections and similar from ALPINE to calibrate UV luminosity-L[CII] and stellar mass-L[CII] relations at z∼7. Given the challenge in precisely defining a selection volume for the REBELS sample itself, we rely on published UV LF and stellar mass function (SMF) determinations at z∼7 and three complementary approaches to derive the [CII] LF. The UV LF-based method provides a lower limit on the [CII] LF, due to its missing the most dust-obscured systems. Our SMF-based estimate yields a Schechter function with a characteristic luminosity of L*[CII]=109.11+0.11−0.27 L⊙ and a steep faint-end slope. From z∼7 to z∼5, our inferred [CII] LF shows an evolution of +0.3 dex in normalisation and +0.1 dex in L*[CII]. Our results indicate a general underprediction from models of the abundance of [CII] emitters at high-redshift and thus potentially the number densities of massive yet UV-faint systems implied by our SMF-based method. Additionally, they suggest that 63% of the star formation rate density occurs in massive [CII]-bright systems and that ∼60-90% of [CII] emitters at z∼7 may be missed by bright UV selections. This highlights the importance of surveys focusing on especially massive, UV-faint sources at z>6.
Related
- Cosmic Collisions I: Optical Morphologies for MIRI-selected galaxies from the PRIMER survey
- The JWST Emission Line Survey (JELS): A narrow-band determination of the Hα Luminosity Function and Cosmic Star Formation into the Epoch of Reionization
- A Suppressed Volumetric Rate of High-Luminosity Mid-Infrared Selected Tidal Disruption Events
- Local luminosity functions of galaxies at (sub)millimeter wavelengths from Planck surveys
- When X-ray Features Fail to Identify Intrinsic Emitters: Label Noise and Luminosity Overlap in Machine Learning Classification of AGN and Star-forming Galaxies
BibTeX
@misc{herarddemanche2026alma,
title = {{The ALMA REBELS Survey: The [C II] Luminosity Function of UV-Selected Galaxies at $z\sim7$}},
author = {Thomas Herard-Demanche and Pascal A. Oesch and Rychard Bouwens and Jacqueline A. Hodge and Hiddo S. B. Algera and Manuel Aravena and Karin Cescon and Elisabete da Cunha and Pratika Dayal and Andrea Ferrara and Rebecca Fisher and Yoshinobu Fudamoto and Kasper E. Heintz and Hanae Inami and Andrea Pallottini and Lucie E. Rowland and Renske Smit and Laura Sommovigo and Mauro Stefanon and Michael W. Topping and Paul van der Werf and Ivana F. van Leeuwen},
howpublished = {arXiv},
year = {2026},
month = oct,
doi = {10.48550/arxiv.2610.27052},
eprint = {2610.27052},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2610.27052},
}
RIS
TY - UNPB
TI - The ALMA REBELS Survey: The [C II] Luminosity Function of UV-Selected Galaxies at z∼7
AU - Thomas Herard-Demanche
AU - Pascal A. Oesch
AU - Rychard Bouwens
AU - Jacqueline A. Hodge
AU - Hiddo S. B. Algera
AU - Manuel Aravena
AU - Karin Cescon
AU - Elisabete da Cunha
AU - Pratika Dayal
AU - Andrea Ferrara
AU - Rebecca Fisher
AU - Yoshinobu Fudamoto
AU - Kasper E. Heintz
AU - Hanae Inami
AU - Andrea Pallottini
AU - Lucie E. Rowland
AU - Renske Smit
AU - Laura Sommovigo
AU - Mauro Stefanon
AU - Michael W. Topping
AU - Paul van der Werf
AU - Ivana F. van Leeuwen
PY - 2026
DA - 2026/10/23
PB - arXiv
DO - 10.48550/arxiv.2610.27052
UR - https://arxiv.org/abs/2610.27052
AB - Luminosity functions (LF) are some of the most basic quantities providing insights into galaxy evolution across cosmic time and enabling a direct comparison between observations and simulations. Here, we present the first [CII]158μm LF at z∼7 from a sizeable UV-selected ALMA sample. Our analysis makes use of 27 galaxies with significant [CII] emission line detections in the epoch of reionization from the REBELS (Reionization Era Bright Emission Line Survey) ALMA Large Program and its pilot programs. We used these line detections and similar from ALPINE to calibrate UV luminosity-L_[CII] and stellar mass-L_[CII] relations at z∼7. Given the challenge in precisely defining a selection volume for the REBELS sample itself, we rely on published UV LF and stellar mass function (SMF) determinations at z∼7 and three complementary approaches to derive the [CII] LF. The UV LF-based method provides a lower limit on the [CII] LF, due to its missing the most dust-obscured systems. Our SMF-based estimate yields a Schechter function with a characteristic luminosity of L^*_[CII]=10^9.11^+0.11_−0.27 L_⊙ and a steep faint-end slope. From z∼7 to z∼5, our inferred [CII] LF shows an evolution of +0.3 dex in normalisation and +0.1 dex in L^*_[CII]. Our results indicate a general underprediction from models of the abundance of [CII] emitters at high-redshift and thus potentially the number densities of massive yet UV-faint systems implied by our SMF-based method. Additionally, they suggest that 63% of the star formation rate density occurs in massive [CII]-bright systems and that ∼60-90% of [CII] emitters at z∼7 may be missed by bright UV selections. This highlights the importance of surveys focusing on especially massive, UV-faint sources at z>6.
ER -