PANORAMIC: The Dawn of Massive Quiescent Galaxies. I. Number Density and Cosmic Variance from 1000 arcmin ² NIRCam Imaging
11 affiliations
- 1University of Arizona
- 2NSF–DOE Vera C. Rubin Observatory/NSF NOIRLab
- 3University of Geneva
- 4Princeton University
- 5University of Copenhage
- 6University of Pittsburgh
- 7University of Massachusetts
- 8Cosmic Dawn Center (DAWN)
- 9University of Toronto
- 10Swinburne University of Technology
- 11Space Telescope Science Institute
Abstract
We measure the number density and field-to-field variance of massive quiescent galaxies at z ∼ 3–8 using the JWST/NIRCam pure-parallel imaging survey PANORAMIC together with archival observations, covering an area of 0.28 deg ² (∼1000 arcmin ² ) in at least six filters. We identify quiescent galaxy candidates at z ≳ 3 with M * ≳ 10 ¹⁰ M ⊙ , comprising 101 galaxies in a gold sample of high-confidence candidates and 137 in a more inclusive silver sample. We measure their evolving comoving number density, finding (1.5 versus 3.1) × 10 ⁻⁵ Mpc ⁻³ at z = 3–4 for the gold and silver samples, respectively, and a decline by more than a factor of 20 by z ∼ 6. Comparisons with empirical models and cosmological simulations show that widely used frameworks underpredict the abundance of massive quiescent galaxies at z ≳ 4 by ≳1 dex, indicating that current implementations of early star formation, feedback, and quenching do not produce enough early quenched systems. With 34 independent sight lines, we present the first direct empirical measurement of field-to-field variance for quiescent galaxies at z > 3, finding a high cosmic variance of σ CV ≈ 0.7 ± 0.3. This exceeds predictions from abundance-matched mock catalogs, suggesting that early quiescent galaxies are more strongly clustered, and more likely to be found near one another or in more biased regions, than expected in current galaxy-formation models. Any successful model for the emergence of early massive quiescent galaxies must reproduce both their abundance evolution and their imprint on the large-scale distribution.
Related
- Evolution of the morphology-density and morphology-mass relations of quiescent galaxies at 0.5 {2}lt;z<$ 2.5 in the COSMOS-Web survey
- The Role of Environment in Shaping the Assembly Timelines of Massive Quiescent Galaxies at Cosmic Noon
- Where Galaxies Go to Die: The Environments of Massive Quiescent Galaxies at 3 < z < 5
- How Quickly Did the Giants Form? Constraining the Formation Timescales of Massive Quiescent Galaxies at Cosmic Noon Using Chemical Evolution Modelling
- The Size-Mass Relation and Inside-Out Quenching of Massive Quiescent Galaxies at 2<z<3 with JWST PRIMER and MINERVA
BibTeX
@article{ji2026panoramic,
title = {{PANORAMIC: The Dawn of Massive Quiescent Galaxies. I. Number Density and Cosmic Variance from 1000 arcmin ² NIRCam Imaging}},
author = {Zhiyuan Ji and Christina C. Williams and Peter Behroozi and Andrea Weibel and Christian Kragh Jespersen and Pascal A. Oesch and Rachel Bezanson and Katherine E. Whitaker and Jenny E. Greene and Gabriel Brammer and Pratika Dayal and Ivo Labbé and Sinclaire M. Manning and Pierluigi Rinaldi and Mengyuan Xiao and Yunchong Zhang},
journal = {The Astrophysical Journal},
year = {2026},
month = oct,
doi = {10.3847/1538-4357/aeaa36},
url = {https://iopscience.iop.org/article/10.3847/1538-4357/aeaa36},
note = {CC BY 4.0},
}
RIS
TY - JOUR
TI - PANORAMIC: The Dawn of Massive Quiescent Galaxies. I. Number Density and Cosmic Variance from 1000 arcmin ² NIRCam Imaging
AU - Zhiyuan Ji
AU - Christina C. Williams
AU - Peter Behroozi
AU - Andrea Weibel
AU - Christian Kragh Jespersen
AU - Pascal A. Oesch
AU - Rachel Bezanson
AU - Katherine E. Whitaker
AU - Jenny E. Greene
AU - Gabriel Brammer
AU - Pratika Dayal
AU - Ivo Labbé
AU - Sinclaire M. Manning
AU - Pierluigi Rinaldi
AU - Mengyuan Xiao
AU - Yunchong Zhang
PY - 2026
DA - 2026/10/26
JO - The Astrophysical Journal
DO - 10.3847/1538-4357/aeaa36
UR - https://iopscience.iop.org/article/10.3847/1538-4357/aeaa36
AB - We measure the number density and field-to-field variance of massive quiescent galaxies at z ∼ 3–8 using the JWST/NIRCam pure-parallel imaging survey PANORAMIC together with archival observations, covering an area of 0.28 deg ² (∼1000 arcmin ² ) in at least six filters. We identify quiescent galaxy candidates at z ≳ 3 with M * ≳ 10 ¹⁰ M ⊙ , comprising 101 galaxies in a gold sample of high-confidence candidates and 137 in a more inclusive silver sample. We measure their evolving comoving number density, finding (1.5 versus 3.1) × 10 ⁻⁵ Mpc ⁻³ at z = 3–4 for the gold and silver samples, respectively, and a decline by more than a factor of 20 by z ∼ 6. Comparisons with empirical models and cosmological simulations show that widely used frameworks underpredict the abundance of massive quiescent galaxies at z ≳ 4 by ≳1 dex, indicating that current implementations of early star formation, feedback, and quenching do not produce enough early quenched systems. With 34 independent sight lines, we present the first direct empirical measurement of field-to-field variance for quiescent galaxies at z > 3, finding a high cosmic variance of σ CV ≈ 0.7 ± 0.3. This exceeds predictions from abundance-matched mock catalogs, suggesting that early quiescent galaxies are more strongly clustered, and more likely to be found near one another or in more biased regions, than expected in current galaxy-formation models. Any successful model for the emergence of early massive quiescent galaxies must reproduce both their abundance evolution and their imprint on the large-scale distribution.
SN - 0004-637X
SN - 1538-4357
ER -