arxiv: 2604.05022 · v1 · submitted 2026-04-06 · 🌌 astro-ph.GA

PANORAMIC: The Dawn of Massive Quiescent Galaxies I. Number Density and Cosmic Variance from 1000 arcmin² NIRCam Imaging

Zhiyuan Ji , Christina C. Williams , Peter Behroozi , Andrea Weibel , Christian Kragh Jespersen , Pascal A. Oesch , Rachel Bezanson , Katherine E. Whitaker

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Jenny E. Greene Gabriel Brammer Pratika Dayal Ivo Labb\'e Sinclaire M. Manning Pierluigi Rinaldi Mengyuan Xiao Yunchong Zhang

This is my paper

Pith reviewed 2026-05-10 19:05 UTC · model grok-4.3

classification 🌌 astro-ph.GA

keywords massive quiescent galaxiesnumber densitycosmic variancehigh-redshift galaxiesJWST NIRCamgalaxy formation modelsearly universe

0 comments p. Extension

The pith

JWST imaging finds massive quiescent galaxies at z>4 are over 10 times more abundant than current models predict.

A machine-rendered reading of the paper's core claim, the machinery that carries it, and where it could break.

The authors use a large 1000 arcmin² JWST NIRCam dataset to count massive quiescent galaxies at redshifts 3 to 8. They report number densities that start at roughly 1.5 times 10 to the minus 5 per cubic megaparsec at z=3-4 and drop sharply by z=6. Widely used empirical models and cosmological simulations underpredict this abundance by at least a factor of 10 at z greater than or equal to 4. The data also show a high field-to-field variance of about 0.7, higher than mock catalogs expect, which points to stronger clustering than current galaxy formation recipes produce.

Core claim

From 101 gold-sample and 137 silver-sample candidates with stellar masses above 10^10 solar masses identified in six or more NIRCam filters, the comoving number density of massive quiescent galaxies declines by more than a factor of 20 from z=3-4 to z~6. This observed abundance exceeds predictions from empirical models and simulations by greater than or equal to 1 dex at z greater than or equal to 4. With 34 independent sightlines the measured cosmic variance reaches sigma_CV approximately 0.7 plus or minus 0.3, exceeding abundance-matched mocks and indicating that early quiescent systems are more clustered than current models assume.

What carries the argument

Photometric selection of quiescent candidates from multi-band NIRCam imaging across 0.28 square degrees, used to derive both number density evolution and direct empirical cosmic variance.

If this is right

Galaxy formation models require earlier or more efficient quenching to produce enough massive quiescent systems by z greater than 4.
The high observed clustering implies that early quiescent galaxies form preferentially in overdense regions.
Successful models must simultaneously match both the abundance evolution and the large-scale spatial distribution of these galaxies.
The measured densities provide a quantitative benchmark for testing implementations of early star formation, feedback, and quenching.

Where Pith is reading between the lines

These are editorial extensions of the paper, not claims the author makes directly.

Quenching processes such as AGN-driven outflows or rapid morphological changes may need to operate at higher redshifts than most current recipes assume.
The excess clustering could mean these galaxies trace the most biased peaks of the density field, with possible knock-on effects for early large-scale structure growth.
Deeper or wider surveys could test whether the abundance continues to rise or plateaus at even earlier times.

Load-bearing premise

The color and spectral-energy-distribution criteria cleanly separate true quiescent galaxies from dusty star-forming contaminants or incomplete samples at z greater than 3.

What would settle it

Deep spectroscopy of the gold-sample candidates at z>4 that either confirms or rejects the quiescent classification for a statistically significant fraction would directly test whether the reported number densities are correct.

Figures

Figures reproduced from arXiv: 2604.05022 by Andrea Weibel, Christian Kragh Jespersen, Christina C. Williams, Gabriel Brammer, Ivo Labb\'e, Jenny E. Greene, Katherine E. Whitaker, Mengyuan Xiao, Pascal A. Oesch, Peter Behroozi, Pierluigi Rinaldi, Pratika Dayal, Rachel Bezanson, Sinclaire M. Manning, Yunchong Zhang, Zhiyuan Ji.

**Figure 1.** Figure 1: Quiescent galaxies at z ∼ 3–8 (a total of 406) identified in this work from ∼1000 arcmin2 of JWST/NIRCam imaging. Galaxies in the gold and silver samples are shown as filled and open symbols, respectively (see Section 3). Massive systems with M∗ ≥ 1010M⊙ – the main focus of this study (101 in the gold sample and 137 in the silver sample) – are shown as stars, while less massive ones are shown as circles. F… view at source ↗

**Figure 2.** Figure 2: The distribution of z ∼ 3–8 quiescent galaxies in the observed F150W−F277W vs. F277W−F444W (left) and the rest-frame U − V vs. V − J (right) color planes. The upper and lower rows show the gold and silver samples, respectively (Section 3.2). Gray contours show all galaxies in the photometric catalog of Weibel et al. (2025c) with zphot > 3 and S/N > 5 in F150W, F277W, and F444W. The green solid lines repres… view at source ↗

**Figure 3.** Figure 3: Left: M∗ vs. zphot for our final samples of quiescent galaxies. The gold sample is shown as filled circles, and the silver sample as open circles. This study focuses on massive systems with M∗ > 1010M⊙. Right: Median best-fit SEDs of > 1010M⊙ quiescent galaxies in three redshift bins: 3 ≤ z < 3.5 (magenta), 3.5 ≤ z < 4.5 (red), and z ≥ 4.5 (orange). The shaded regions represent the 1-σ uncertainties, deriv… view at source ↗

**Figure 4.** Figure 4: SFR vs. M∗. Quiescent galaxies in the gold and silver samples are shown as filled and open circles, respectively. Stellar masses and SFRs are plotted as the mean from the three SED fittings described in Section 3.2, with error bars indicating the full range spanned by these fittings. The magenta and green solid lines show the star-forming main sequence at z = 3 and z = 8 from Popesso et al. (2023), while… view at source ↗

**Figure 5.** Figure 5: Candidates of massive quiescent galaxies at z ∼ 6 in our gold sample that have not yet been spectroscopically confirmed. For each object, we show the JWST image cutout and observed SED with the best-fit model (left), the posterior constraints on photometric redshift and specific star formation rate (middle), and the inferred star-formation history (right) from the continiuty SFH SED fitting. at M∗ ≥ 1010M⊙… view at source ↗

**Figure 6.** Figure 6: Cosmic number density of z ≥ 3 quiescent galaxies with M∗ ≥ 1010M⊙ and sSFR < 0.2/tH (Section 3). Hatched regions show the measurements (1σ range) obtained with the probabilistic approach (including the cosmic-variance error) described in Section 4.1, which fully accounts for the posterior distributions of redshift and sSFR. The regions with solid, dashed, and dotted edges correspond to the results based o… view at source ↗

**Figure 7.** Figure 7: Similar to [PITH_FULL_IMAGE:figures/full_fig_p012_7.png] view at source ↗

**Figure 8.** Figure 8: Comparison of the cosmic number density of quiescent galaxies with predictions from simulations and SAMs (left) and from the UniverseMachine empirical framework (right). All models adopt the same stellar mass cut (≥ 1010M⊙) and sSFR threshold (< 0.2/tH) as the observations. Simulations include IllustrisTNG (Pillepich et al. 2018), Eagle (Schaye et al. 2015), Simba (Dav´e et al. 2019), Flamingo (Schaye et a… view at source ↗

**Figure 9.** Figure 9: Comparison of bootstrap-inferred cosmic variance (Equation 12, on the scale of a single NIRCam pointing), σCV, between the observed gold+silver quiescent sample and the sSFR-abundance-matched UniverseMachine mocks using the same number of sightlines. The filled histograms show the differential distributions of σCV, while the solid curves show the corresponding cumulative probabilities (right axis). The… view at source ↗

**Figure 10.** Figure 10: MCMC-inferred cosmic variance. Top: Observational constraints for our gold+silver sample of massive quiescent galaxies at z > 3. Left panel shows the probability distribution of the number of galaxies per pointing, N (black points with uncertainties from bootstrap resampling). The dashed curve indicates the MCMC best-fit model (see Section 5.1.1), with the shaded band showing the posterior predictive 1-σ … view at source ↗

**Figure 11.** Figure 11: Examples from our re-analysis of the full sample of z ∼ 7 quiescent candidates with (F277W − F444W) > 1 mag. For each source, the left panel shows the best-fitting Prospector SED model (no LRD component included) assuming a continuity SFH, with the inset showing the 2”×2” NIRCam cutout, while the right panel shows the best-fitting EAzY template and the dashed red curve indicates the contribution from the … view at source ↗

**Figure 12.** Figure 12: Expected constraints on the cosmic variance, σCV, as a function of the number of independent sightlines, in units of the current sample size. The points and error bars show the inferred σCV and its uncertainty assuming the same underlying value as measured in this work, with “1×” corresponding to the present dataset of 34 sightlines. The labels at the top indicate approximate observational regimes, from … view at source ↗

**Figure 13.** Figure 13: HST (black) and NIRCam (orange) photometric comparison for the initially selected galaxies in GOODS-S. The x-axis shows the photometry from our pipeline (Section 2), and the y-axis shows the measurements from the latest JADES DR5. The fluxes are given in units of nJy. The green dashed line marks the one-to-one relation. The two sets of photometry are highly consistent within the uncertainties. APPENDIX A.… view at source ↗

**Figure 14.** Figure 14: Comparisons of the inferred properties assuming three different SFHs (Section 3.2) for the initial sample of 2633 galaxies (Section 3.1). The green dashed line marks the one-to-one relation. For clarity, galaxies with SFR < 10−3 M⊙ yr−1 are all plotted at 10−3 M⊙ yr−1 . Galaxies with sSFR ≤ 10−10 yr−1 from the non-parametric continuity prior are highlighted in red, showing the large systematic uncertainti… view at source ↗

**Figure 15.** Figure 15: Comparison of our SED-derived properties with those reported in the literature for the 28 spectroscopically confirmed quiescent galaxies at z > 3. Results assuming the continuity, delayed-τ , and bursty-continuity SFHs are shown as black and grey filled circles, and black open circles, respectively. The black solid line indicates the one-to-one relation. Left: photometric versus spectroscopic redshifts, w… view at source ↗

**Figure 16.** Figure 16: Left panel is similar to [PITH_FULL_IMAGE:figures/full_fig_p031_16.png] view at source ↗

read the original abstract

We measure the number density and field-to-field variance of massive quiescent galaxies at $z\sim3$ - 8 using the JWST/NIRCam pure-parallel imaging survey PANORAMIC together with archival observations, covering an area of 0.28 deg$^2$ ($\sim1000$ arcmin$^2$) in at least six filters. We identify quiescent galaxy candidates at $z\gtrsim3$ with $M_\ast \gtrsim 10^{10}\,M_\odot$, 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 $(1.5$ vs. $3.1)\times10^{-5}\,\mathrm{Mpc}^{-3}$ at $z=3$ - 4 for the gold and silver samples, respectively, and a decline by more than a factor of 20 by $z\sim6$. Comparisons with empirical models and cosmological simulations show that widely used frameworks underpredict the abundance of massive quiescent galaxies at $z\gtrsim4$ by $\gtrsim1$ dex, indicating that current implementations of early star formation, feedback, and quenching do not produce enough early quenched systems. With 34 independent sightlines, we present the first direct empirical measurement of field-to-field variance for quiescent galaxies at $z>3$, finding a high cosmic variance of $\sigma_{\rm CV}\approx0.7\pm0.3$. 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.

Editorial analysis

A structured set of objections, weighed in public.

Desk editor's note, referee report, simulated authors' rebuttal, and a circularity audit. Tearing a paper down is the easy half of reading it; the pith above is the substance, this is the friction.

Desk Editor's Note private letter to a colleague

This JWST survey gives the first direct cosmic variance for massive quiescent galaxies at z>3 and shows models underpredict their numbers by ~1 dex at z>4, but the result depends on how cleanly the photometric samples separate true quiescents from contaminants.

read the letter

The main thing to know is that PANORAMIC measures number densities of massive quiescent galaxies that sit well above what most simulations and empirical models produce at z greater than 4, while also reporting a high field-to-field variance of about 0.7 from 34 separate sightlines. That variance result is genuinely new and points to stronger clustering than current mocks expect. The abundance drop by more than a factor of 20 from z=3-4 to z~6 is also pinned down over a larger area than previous work. The paper does a straightforward job of laying out the gold and silver candidate samples from the 1000 arcmin² NIRCam coverage and comparing them directly to external benchmarks. The 34 independent fields give a real empirical handle on cosmic variance that earlier smaller surveys could not provide. The soft spot is the photometric selection itself. Both quiescent and dusty star-forming galaxies can occupy similar regions in NIRCam color space at these redshifts, so any non-negligible contamination in the gold or silver samples would inflate the densities and reduce or remove the reported tension with models. The abstract gives no completeness fractions, purity estimates, or detailed error budget, which leaves the central discrepancy claim resting on an assumption that needs explicit checks in the methods. This work is aimed at people modeling early quenching and feedback, and at observers planning follow-up on high-z red galaxies. It deserves a serious referee because the survey area and sightline count are real advances, even if the selection details will require close scrutiny before the model shortfall can be taken as settled.

Referee Report

1 major / 2 minor

Summary. The paper measures the comoving number density and field-to-field cosmic variance of massive quiescent galaxies (M* ≳ 10^10 M⊙) at z ∼ 3–8 using JWST/NIRCam pure-parallel imaging over ∼1000 arcmin² (0.28 deg²) from the PANORAMIC survey plus archival data. It identifies 101 high-confidence gold-sample and 137 more inclusive silver-sample candidates, reports densities of (1.5 vs. 3.1) × 10^{-5} Mpc^{-3} at z = 3–4 that decline by more than a factor of 20 by z ∼ 6, and finds that empirical models and cosmological simulations underpredict the observed abundances by ≳1 dex at z ≳ 4. From 34 independent sightlines it also reports a high cosmic variance σ_CV ≈ 0.7 ± 0.3 that exceeds abundance-matched mock predictions, implying stronger clustering than current models produce.

Significance. If the photometric selections prove robust, the work supplies important empirical benchmarks on the abundance and spatial distribution of the earliest massive quiescent systems, directly testing whether current implementations of star formation, feedback, and quenching can produce sufficient early quenched galaxies. The large contiguous area and 34 independent fields enable the first direct measurement of cosmic variance at these redshifts, a clear methodological strength that goes beyond single-field studies.

major comments (1)

[Candidate Selection and Sample Definition] The central claim that models underpredict the abundance of massive quiescent galaxies by ≳1 dex at z ≳ 4 rests on the reported number densities being free of substantial contamination. The gold and silver samples are defined via photometric color cuts and SED fitting, yet the manuscript provides no quantitative completeness or contamination fractions (particularly from dusty star-forming galaxies whose rest-frame optical colors can overlap at z > 3). This purity assessment is load-bearing for the model-discrepancy conclusion and must be supplied with explicit tests or simulations before the tension can be considered secure.

minor comments (2)

[Abstract] The abstract states “at least six filters” without listing the specific NIRCam bands or their 5σ depths; adding these details would improve reproducibility.
[Results] The error budget on the number densities and the cosmic-variance measurement should be broken down explicitly (Poisson, cosmic variance, photometric redshift, and selection uncertainties) rather than quoted only as a combined ±0.3 on σ_CV.

Simulated Author's Rebuttal

1 responses · 0 unresolved

We thank the referee for their constructive and detailed report. We agree that a quantitative assessment of sample completeness and contamination is essential to support the claimed tension with models, and we address this point below. We will incorporate the requested analyses in the revised manuscript.

read point-by-point responses

Referee: [Candidate Selection and Sample Definition] The central claim that models underpredict the abundance of massive quiescent galaxies by ≳1 dex at z ≳ 4 rests on the reported number densities being free of substantial contamination. The gold and silver samples are defined via photometric color cuts and SED fitting, yet the manuscript provides no quantitative completeness or contamination fractions (particularly from dusty star-forming galaxies whose rest-frame optical colors can overlap at z > 3). This purity assessment is load-bearing for the model-discrepancy conclusion and must be supplied with explicit tests or simulations before the tension can be considered secure.

Authors: We thank the referee for identifying this critical aspect of our analysis. We agree that the distinction between the gold and silver samples, while intended to bracket confidence levels, does not by itself constitute a quantitative purity assessment, and that potential contamination from dusty star-forming galaxies at z > 3 requires explicit evaluation given the overlap in rest-frame optical colors. In the revised manuscript we will add a new subsection (likely Section 3.3 or equivalent) that presents completeness and contamination fractions derived from two complementary approaches: (1) insertion of mock quiescent and dusty star-forming galaxies into the PANORAMIC imaging using the survey's actual depth, filter set, and noise properties, and (2) forward-modeling of SEDs drawn from empirical templates and from the same cosmological simulations we compare against. These tests will quantify the fraction of contaminants that pass both the color cuts and the SED-fitting criteria used for the gold sample, with particular attention to z > 3 dusty interlopers. We will also report the resulting purity-corrected number densities and discuss how they affect the model comparison. revision: yes

Circularity Check

0 steps flagged

Direct counts from photometric samples with external model comparisons exhibit no circularity.

full rationale

The paper's central results consist of number densities computed from direct counts of galaxies in the gold and silver samples, which are defined by applying photometric selection criteria to the NIRCam imaging data. These densities are then compared against independent empirical models and cosmological simulations as external benchmarks. No steps reduce by construction to fitted parameters, self-definitions, or self-citation chains within the paper's own equations; the abundance evolution and cosmic variance measurements are observationally derived quantities whose tension with models is presented as a factual discrepancy rather than a tautological outcome.

Axiom & Free-Parameter Ledger

0 free parameters · 1 axioms · 0 invented entities

The central claim rests on photometric identification of quiescent systems and conversion of observed areas/redshifts to comoving volumes under standard cosmology; no new entities or fitted parameters are introduced for the measurement itself.

axioms (1)

standard math Standard flat Lambda-CDM cosmology for comoving volume and distance calculations
Invoked to translate observed sky area and photometric redshifts into comoving number densities at z=3-8.

pith-pipeline@v0.9.0 · 5734 in / 1285 out tokens · 76542 ms · 2026-05-10T19:05:29.980286+00:00 · methodology

discussion (0)

Lean theorems connected to this paper

Citations machine-checked in the Pith Canon. Every link opens the source theorem in the public Lean library.

IndisputableMonolith/Foundation/AbsoluteFloorClosure.lean reality_from_one_distinction unclear

?

unclear
Relation between the paper passage and the cited Recognition theorem.

We measure the number density ... using ... PANORAMIC ... 101 galaxies in a gold sample ... probabilistic framework ... P_Q^i(z_k) ... cosmic variance σ_CV ≈0.7±0.3
IndisputableMonolith/Cost/FunctionalEquation.lean washburn_uniqueness_aczel unclear

?

unclear
Relation between the paper passage and the cited Recognition theorem.

Comparisons with ... simulations show ... underpredict the abundance ... by ≳1 dex

What do these tags mean?

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supports: The theorem supports part of the paper's argument, but the paper may add assumptions or extra steps.
extends: The paper goes beyond the formal theorem; the theorem is a base layer rather than the whole result.
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contradicts: The paper's claim conflicts with a theorem or certificate in the canon.
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Forward citations

Cited by 1 Pith paper

Reviewed papers in the Pith corpus that reference this work. Sorted by Pith novelty score.

A Census of Na D-traced neutral ISM and outflows at $0.6<z<4$
astro-ph.GA 2026-04 unverdicted novelty 7.0

A JWST census detects neutral ISM absorption in 76 of 309 galaxies at 0.6<z<4 and outflows in 26, indicating AGN-driven neutral outflows dominate in quiescent systems at cosmic noon.

Reference graph

Works this paper leans on

9 extracted references · 9 canonical work pages · cited by 1 Pith paper

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modeled as a piecewise step function composed of nine lookback time bins. The first two bins are fixed to 0−30 and 30−100 Myr; the last bin is fixed to 0.85tH −t H wheret H is the Hubble time at the epoch of observation; the remaining six bins are evenly spaced in logarithmic time between 100 Myr and 0.85tH. Changes in SFR between adjacent bins,x= log(SFR...

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Cross-matching with the GOODS-S AGN catalog of Lyu et al

are available. Cross-matching with the GOODS-S AGN catalog of Lyu et al. (2024), which uses multiwavelength (X-ray to radio) criteria, we find that 4 of 42 (≈9.5%) massive (>10 10 M⊙) galaxies in our gold+silver samples are classified as AGN. Using the AGN-inclusive SED fits from Lyu et al. (2024), we find that the rest-frame UV–NIR SEDs of these four gal...

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In addition, Zhang et al

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Among the 79 galaxies reported, we found that 35 (after removing duplicates) lie atz≥3 and fall within our imaging coverage with 6-band NIRCam photometry

reported quiescent galaxies from the RUBIES program confirmed with JWST/NIRSpec spectroscopy. Among the 79 galaxies reported, we found that 35 (after removing duplicates) lie atz≥3 and fall within our imaging coverage with 6-band NIRCam photometry. Since the list of Antwi-Danso et al. (2025) includes a few galaxies from earlier studies based on low-S/N gr...

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Results assuming the continuity, delayed-τ, and bursty-continuity SFHs are shown as black and grey filled circles, and black open circles, respectively

For redshifts, our photometric values are in excellent agreement with spectroscopic 30 3.00 3.25 3.50 3.75 4.00 4.25 4.50 4.75 5.00 zphot 3.00 3.25 3.50 3.75 4.00 4.25 4.50 4.75 5.00 zspec Continiuty Delayed-tau Bursty continuty 10.0 10.2 10.4 10.6 10.8 11.0 11.2 11.4 log M* M (this work) 10.0 10.2 10.4 10.6 10.8 11.0 11.2 11.4 log M* M (previous) Figure ...

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piles up

The middle and right panels are similar to Figure 10, but show the MCMC-fitting inferredσ CV for the gold sample; theσ CV posterior “piles up” at zero. Together, these results indicate that the gold sample alone lacks sufficient statistics for a robust cosmic-variance measurement. where⟨N⟩is the mean number of objects per sightline. Replacing the underlyi...

work page 2002