Pith. sign in

REVIEW 4 major objections 5 minor 146 references

Little Red Dots show H-alpha variability of at most about 4 percent on monthly timescales—far below the ~6 percent red-noise flicker of normal quasars—suggesting their broad-line light is produced differently.

Reviewed by Pith at T0; open to challenge. T0 means a machine referee read the full paper against a public rubric. the ladder, T0–T4 →

Challenge this review Re-run · record.json Download PDF Read on arXiv ↗

T0 review

2026-08-04 23:36 UTC pith:M4ERO5Y7

load-bearing objection First systematic NIRSpec multi-epoch H-alpha variability sample for LRDs gives a plausible 4% upper limit, but the local-continuum normalization can suppress exactly the variability it measures, so the white-noise conclusion is not yet solid. the 4 major comments →

arxiv 2608.01647 v1 pith:M4ERO5Y7 submitted 2026-08-03 astro-ph.GA

NEXUS: Spectral Variability of Little Red Dots and Blue Active Galactic Nuclei at 2 lesssim z lesssim 6

Zachary Stone , Yue Shen , Ming-Yang Zhuang , Junyao Li , Zhiwei Pan , Jenny E. Greene , Feige Wang This is my paper
classification astro-ph.GA
keywords Little Red DotsAGN variabilityH-alpha emissionJWST NIRSpec spectroscopyHigh-redshift galaxiesSupermassive black holesBroad-line regionBalmer decrement
verification ladder T0 review T1 audit T2 compute T3 formal T4 reserved

The pith

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

This paper tries to establish that Little Red Dots—compact, red, high-redshift sources thought to harbor accreting supermassive black holes—show almost no H-alpha or rest-optical continuum variability on rest-frame timescales of about one to three months, and that the little variability they do show is consistent with white noise rather than the red-noise flicker of normal quasars. Using multi-epoch JWST spectroscopy of 17 LRDs and 14 blue broad-line AGNs, the authors measure an intrinsic H-alpha rms variability of at most about 4 percent for the LRD population, compared with about 6 percent for a luminosity-matched low-redshift AGN sample over the same timescales. They also find enhanced Balmer decrements (median H-alpha/H-beta around 7.6) in LRDs. If the claim holds, the broad-line emission in LRDs is probably not produced by the same reverberation-driven mechanism as in ordinary AGNs, which would reshape theoretical models of these objects and of early black-hole growth.

Core claim

The central claim is that, as a population, LRDs have intrinsic H-alpha flux variability of about 4 percent rms or less on rest-frame timescales under roughly 100 days, with rest-optical continuum variability below about 3 percent, while luminosity-matched low-redshift AGNs show about 6 percent monthly H-alpha variability with a red-noise structure function that grows with timescale. Combining the present multi-epoch NIRSpec measurements with published LRD variability measurements on roughly six-month to decade timescales, the paper argues that LRD variability is flat—white-noise-like—across all sampled timescales, in both H-alpha and continuum. The authors present this as evidence that the

What carries the argument

The load-bearing tool is the maximum-likelihood intrinsic rms variability estimator sigma_0, applied to pairwise fractional H-alpha flux differences between epochs: the paper symmetrizes the difference distribution with negative duplicates and divides the resulting scatter by the square root of two to obtain a sample-wide light-curve rms, sigma_0,lc. This estimator separates true source variability from per-epoch measurement noise, allowing 12 LRDs to be compared statistically with 56 low-redshift SDSS-RM AGNs. The secondary machinery is the ensemble structure function built from SDSS-RM H-alpha light curves, which supplies the red-noise baseline, together with a local-continuum normalizatio

Load-bearing premise

The load-bearing premise is that the LRD continuum is steady over the observed months, so dividing each epoch spectrum by its local continuum only corrects slit losses—an assumption supported by difference-imaging photometry from the first three epochs, since if the continuum actually varies the normalization would cancel the associated line variability and could create the flat low-amplitude pattern the paper reports.

What would settle it

Take the same or a larger LRD sample and normalize every NIRSpec epoch using independent difference-imaging photometry for all epochs rather than the spectral continuum. If the resulting H-alpha rms variability exceeds about 6 percent on rest-frame timescales below 100 days, or if the structure function rises with timescale instead of staying flat, the white-noise, weak-variability conclusion fails.

Watch this falsifier. Get emailed when new claim-graph text bears on it.

Share X Bluesky LinkedIn Reddit HN

If this is right

  • If LRDs genuinely vary as white noise, standard reverberation-mapping campaigns will not detect correlated H-alpha responses on monthly cadences, and black-hole masses for LRDs cannot be derived the usual way.
  • The flat structure function means longer baselines do not accumulate variability signal the way they do for normal AGNs; detecting real LRD variability will require much larger samples or rare individual objects, not simply longer monitoring.
  • Models that predict normal AGN-like ionizing-flux flicker, and hence roughly 6 percent monthly broad-line variability, are disfavored for the bulk of the LRD population, while dense-envelope or super-Eddington models that damp short-term variability are favored.
  • The enhanced Balmer decrement combined with weak variability points to collisional excitation or radiative transfer in dense gas, rather than dust reddening, as the origin of LRD line ratios.
  • Rare variable LRDs such as NX7607 may be transitional objects or misclassified reddened AGNs, and identifying such objects is a path toward understanding diversity within the population.

Where Pith is reading between the lines

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

  • If the flat variability pattern is real, the reported 4 percent H-alpha upper limit may itself be optimistic: normalizing each epoch to a constant local continuum would erase any line variability that tracks the continuum, so the true line variability could be even lower than measured.
  • The comparison sample is luminosity-matched but not matched in Eddington ratio or black-hole mass; if LRD variability follows the same anti-correlation with accretion rate seen in local AGNs, the observed suppression might reflect extreme super-Eddington accretion rather than a fundamentally different emission mechanism—an alternative the current data may not fully exclude.
  • A direct test would be to obtain difference-imaging photometry for every spectroscopic epoch and normalize each spectrum independently; if the LRD continuum does vary at the roughly 2 percent level, the white-noise conclusion would need revision.
  • The same multi-epoch NIRSpec data could be searched for correlated narrow-line variability, for example in [OIII], which would discriminate between scattered or reprocessed emission and collisionally excited line origins in the dense-gas picture.

Editorial analysis

A structured set of objections, weighed in public.

Desk editor's note, referee report, simulated authors' rebuttal, and a circularity audit.

Referee Report

4 major / 5 minor

Summary. The paper presents multi-epoch JWST/NIRSpec MSA spectroscopy from the first six NEXUS Deep epochs for 17 Little Red Dots and 14 blue broad-line AGNs at 2 ≲ z ≲ 6. After fitting the Hα complex and normalizing each epoch spectrum (local-continuum normalization for LRDs, aperture-photometric normalization for BLAGNs), the authors measure Balmer decrements, line ratios, and Hα and continuum variability. They report that LRDs have enhanced Balmer decrements, low continuum variability (σ0,lc ≈ 2–3%), and low Hα variability (σ0,lc = 4.02%) on rest-frame ~1–3 month timescales, compared with 6.29% for an Hα-luminosity-matched SDSS-RM sample, a difference they quote as 3.8σ. Combining this with literature results at longer timescales, they argue that LRD broad-line variability follows a white-noise pattern, in contrast to the red-noise behavior of normal AGNs, suggesting different broad-line production mechanisms in LRDs.

Significance. If the central result holds, it is valuable: it provides one of the first spectroscopic, ensemble constraints on high-redshift LRD broad-line variability and connects to a growing body of photometric non-detections. The use of an external SDSS-RM comparison sample, the explicit treatment of flux uncertainties via the σ0 maximum-likelihood estimator, and the authors' repeated caution that their estimates are upper limits are strengths. The sample is small (12 LRDs, 26 Hα flux pairs), however, and the headline 4% constraint is conditional on a local-continuum normalization that assumes a non-varying LRD continuum. That assumption, plus the exclusion of the most variable LRD (NX7607), means the population-level claim and the white-noise interpretation are not yet fully secured. With additional robustness tests and more careful reporting of the NX7607 exclusion, the paper would provide a solid upper-limit benchmark for LRD variability models.

major comments (4)
  1. [§3.1, normalization scheme] The LRD normalization divides each epoch's Hα profile by the fitted local continuum and rescales to the epoch with the largest continuum. This removes any fractional flux change that is common to Hα and the adjacent continuum. In the standard AGN reverberation picture the paper contrasts with, a few-percent ionizing-continuum change over 1–3 months would induce a proportional Hα response, so the normalization would suppress exactly the signal the paper aims to measure. The only direct evidence that the LRD continuum is constant comes from difference-image photometry of the first three Deep imaging epochs (§4.3), whereas the spectroscopic variability uses up to six MSA epochs; raw F200W aperture photometry shows ~6% scatter, comparable to the quoted 4% Hα rms. Thus σ0,lc = 4.02% (Table 3) is an upper limit only under the assumption of a non-varying LRD rest-optical continuum. Please quant
  2. [§3.3 and Table 3] The text says 'We exclude NX7607 when obtaining σ0,lc, as its ∼30% variability significantly inflates the estimated intrinsic variability,' yet Table 3 lists 'All LRDs' with N_obj = 12, N_pair = 26, and σ0,lc = 4.02%, which appears to include NX7607 (which has 2 reliable epochs in Table 1). No row is given for the sample excluding NX7607, and §4.2 quotes 4.02% as the main LRD result. Please clarify which sample produced the headline value and report both with and without NX7607. Because NX7607 is the single most variable LRD, its inclusion/exclusion is pivotal to the claimed 3.8σ suppression; this must be transparent and not confined to a single sentence.
  3. [§3.3, σ0 estimator] The σ0 estimate is obtained by duplicating all |ΔF| values with negative signs, thereby doubling the number of data points without adding independent information. The quoted uncertainty (e.g., 4.02+0.59, Table 3) is therefore likely optimistic. With only 26 independent flux pairs from 12 LRDs, the 3.8σ excess over SDSS-RM is fragile. Please validate with bootstrap resampling of the 26 pairs and with one-object-out/jackknife tests, and state the number of independent (non-duplicated) pairs when quoting significances. The SDSS-RM uncertainty is tiny because of its large pair count; the comparison error is dominated by the LRD side, so a proper small-sample treatment is essential.
  4. [§4.2 and §5.1, white-noise claim] The conclusion of a 'white-noise pattern across all timescales' is derived by combining the NEXUS 4% upper limit with literature points on yearly-to-decade timescales, several of which are themselves upper limits or marginal detections (TWINKLE; Burke et al. 2026; Furtak et al. 2025). Upper limits cannot demonstrate a flat structure function; they only place an envelope. Moreover, the combined data are heterogeneous (different objects, different normalizations, some photometric, some spectroscopic). Please fit a power-law structure function to the upper limits or provide a statistical test that the ensemble is inconsistent with a red-noise model; otherwise soften the conclusion to 'consistent with low-level variability bounded by current upper limits.'
minor comments (5)
  1. [§3.2, Eq. (1)] The extinction coefficient κ(λ) is used in Eq. (1) before being defined; define R_V and κ in the text immediately before the equation.
  2. [§4.3/Table 3] The F200W 'Typical LRDs' row contains only 1 object and 15 pairs. This is too little to support an ensemble claim; the text should explicitly caution that the F200W typical-LRD constraint is dominated by a single source.
  3. [§6] Typo: 'inclde' should be 'include' in the final paragraph.
  4. [References] A few references are arXiv-only or lack full bibliographic details (e.g., Naidu et al. 2025, Chen et al. 2026, Sneppen et al. 2026). Please ensure all cited works have complete journal/volume/page information where available.
  5. [§3.1, cool LRDs] The cool LRDs are normalized with aperture photometry while typical LRDs use local continuum, yet both are combined in Table 3's 'All LRDs' row. The text should remind the reader of this methodological difference when interpreting the combined σ0,lc.

Circularity Check

0 steps flagged

No circular derivation: the Hα variability constraint is an upper limit with a continuum-normalization caveat, and the SDSS-RM comparison is externally grounded.

full rationale

The paper's central derivation (Hα rms variability of LRDs vs SDSS-RM) is self-contained: the same σ0,lc maximum-likelihood estimator is applied to both NEXUS and SDSS-RM light curves, and the comparison sample is drawn from the public SDSS-RM program. The only quasi-circular element is the local-continuum normalization in Section 3.1, which divides each epoch's line profile by the fitted local continuum. This removes any common-mode line+continuum variability and would bias the measured Hα rms low if LRD continua vary at the few-percent level. However, the paper explicitly justifies this choice with difference-image photometry (Section 4.3, quoting Z. Stone et al. 2025) showing ≲2-3% continuum rms, and labels the derived estimates as upper limits due to systematics. That is an explicit assumption with external empirical support, not a mathematical reduction of the conclusion to the inputs. Self-citations to NEXUS survey papers and the σ0 estimator (Y. Shen et al. 2019) are standard method/data references, not circular premises. No fitted parameter is renamed as a prediction. The white-noise interpretation is a synthesis of several independent upper limits, not a derivation from a self-citation chain. The normalization caveat is a correctness risk, not circularity, so the score is low.

Axiom & Free-Parameter Ledger

2 free parameters · 4 axioms · 0 invented entities

There are no free parameters fitted to data to force the central result; the two hand-chosen thresholds (5% flux cut, 60% LSF inflation) and the domain assumptions about compactness, non-variable continuum, and Gaussian variability underpin the variability measurement.

free parameters (2)
  • 5% flux uncertainty cut = 5%
    Hand-chosen threshold on individual epoch H-alpha flux uncertainties before variability analysis; determines which objects enter the sigma0,lc estimates and directly shapes the reported LRD variability.
  • Line-spread-function resolution increase factor = 60%
    Hand-chosen inflation of the NIRSpec LSF to account for point-source morphology; affects line flux decomposition and uncertainties, though the paper primarily uses integrated fluxes.
axioms (4)
  • domain assumption LRDs are compact, so slit losses affect continuum and emission lines identically
    Invoked in Section 3.1 to justify the local-continuum normalization scheme for LRD spectra.
  • ad hoc to paper The rest-optical continuum of LRDs is not intrinsically variable over ~1-3 month timescales
    Section 3.1: 'Our initial difference-image photometry shows minimal photometric variability... which allows us to use the local spectral continuum to normalize.' Load-bearing, as a varying continuum would cancel real line variability.
  • domain assumption Intrinsic population variability is Gaussian distributed around zero mean
    Section 3.3 footnote 7: 'we assume Gaussian distributions for all underlying population-wide intrinsic variability... necessary given the small sample statistics.'
  • domain assumption SMC extinction curve and Case B recombination intrinsic Balmer ratio for A_V estimates
    Section 3.2: A_V computed assuming SMC extinction (R_V=3.02) and Case B (H-alpha/H-beta)_int. The authors note this is 'probably not true for LRDs' and use A_V only for comparison.

reviewed 2026-08-04 · how reviews work

0 comments
Cite this review

Pith. "Pith review of NEXUS: Spectral Variability of Little Red Dots and Blue Active Galactic Nuclei at $2 \lesssim z \lesssim 6$." pith.science (2026). https://pith.science/paper/M4ERO5Y7

@misc{pith2026260801647,
  author       = {Pith},
  title        = {Pith review of: NEXUS: Spectral Variability of Little Red Dots and Blue Active Galactic Nuclei at $2 \lesssim z \lesssim 6$},
  year         = {2026},
  howpublished = {\url{https://pith.science/paper/M4ERO5Y7}},
  note         = {Machine review of arXiv:2608.01647}
}
Share X Bluesky LinkedIn Reddit HN
read the original abstract

We present spectral measurements for 17 Little Red Dots (LRDs) and 14 blue broad-line active galactic nuclei (AGNs) at $2\lesssim z \lesssim 6$ using multi-epoch JWST NIRSpec MSA spectra from the NEXUS program, sampling rest-frame timescales of $\sim 1-3$ months. Overall, the LRD population shows significantly enhanced Balmer decrement compared with both blue JWST AGNs at similar redshifts and 56 low-redshift broad-line AGNs matched in H$\rm\alpha$ luminosity. The rest-optical continua of LRDs show little ensemble variability (rms $\lesssim 3\%$), and the total H$\rm\alpha$ emission also shows weaker ensemble variability compared with low-redshift AGNs matched in H$\rm\alpha$ luminosity and rest-frame timescales. Based on the flux uncertainties, we constrain the intrinsic H$\rm\alpha$ rms variability to be $\lesssim 4\%$ for the LRD population over these timescales. Combining our results with recent broad-line variability measurements of LRDs over yearly to decade timescales reveals a low-level white-noise pattern across all timescales, in stark contrast to the variability amplitude ($\sim 6\%$ over monthly timescales) and red-noise pattern observed in normal AGNs. These results add to the growing observational studies that suggest population-wise, LRDs have weak variability both in optical continuum and broad-line emission. Furthermore, the distinct white-noise broad-line variability pattern suggests different production mechanisms of broad-line emission in LRDs as opposed to normal AGNs, and/or different properties of the driving ionizing flux from the central engine.

Figures

Figures reproduced from arXiv: 2608.01647 by Feige Wang, Jenny E. Greene, Junyao Li, Ming-Yang Zhuang, Yue Shen, Zachary Stone, Zhiwei Pan.

Figure 1
Figure 1. Figure 1: The NEXUS BLAGNs (blue)/LRDs (red/purple) in Hα luminosity-redshift space The SDSS-RM low-z AGN comparison sample (gray points) and SDSS DR16Q compar￾ison sample (gray contours) are also shown. Objects rep￾resented by filled stars show the subsample considered for our Hα variability analysis. The purple stars represent the subset of LRDs that have “cooler” temperatures (see Sec￾tion 5.2) NIRSpec MSA spectr… view at source ↗
Figure 2
Figure 2. Figure 2: SEDs for our NEXUS BLAGNs (bottom)/LRDs (middle), and the SDSS-RM comparison sample (top). All spectra are shifted to the rest-frame of the source, normalized within the 5400 − 5700 ˚A continuum window, and smoothed with a Gaussian kernel of two pixels. The Balmer break, signifying the supposed location of the “V” within the LRD, is shown with a vertical dotted line. Paschen lines, as well as He iiλ4686, a… view at source ↗
Figure 3
Figure 3. Figure 3: Example line model fits for some objects in our sample. For each source (panel), an example emission line is shown for a particular Deep epoch spectrum. For each panel, the top sub-panel shows the emission line in black, with the 1σ uncertainty shaded in gray, the emission line fit in blue, broad components in cyan, narrow components in orange, and the continuum in red. Some line complexes (e.g., Hα) have … view at source ↗
Figure 4
Figure 4. Figure 4: Normalized multi-epoch Hα line profiles for the broad-line variability sub-sample (Section 3.3), after imposing a < 5% integrated flux uncertainty cut on each epoch. Typical LRDs are labeled in red, and cool LRDs are labeled in purple. is due to dust reddening and the fiducial line ratio is from Case B recombination – though this is probably not true for LRDs. Using individual line ratios, we obtain estima… view at source ↗
Figure 5
Figure 5. Figure 5: Multi-epoch offsets in the peak model Hα flux from our line fitting procedure for the sample of BLAGNs/LRDs (blue/red), as well as a sample of ELGs (gray). Offsets between two epochs are shown as a function of the LSF broadening at Hα. Large offsets can be caused by systematics in MSA spectral reduction, as evidenced by the results for the ELGs. timator σ0 (e.g., Y. Shen et al. 2019). This σ0 metric presen… view at source ↗
Figure 6
Figure 6. Figure 6: Ratios between different Balmer and Paschen lines from our sample. The top row shows ratios from individual deep epoch spectra, while the bottom row shows the weighted mean over all epochs for each object. The colors and transparency of the sources match those in [PITH_FULL_IMAGE:figures/full_fig_p011_6.png] view at source ↗
Figure 7
Figure 7. Figure 7: Estimates of dust extinction AV from the NEXUS BLAGN/LRD sample and SDSS-RM comparison sample. Estimates are obtained using the total integrated fluxes from each line. Faded red circles represent total Balmer decrement AV estimates for LRDs from the literature (Y. Harikane et al. 2023; M. Brooks et al. 2024; I. Juodˇzbalis et al. 2024; I. Labbe et al. 2024; F. D’Eugenio et al. 2025; G. P. Nikopoulos et al.… view at source ↗
Figure 8
Figure 8. Figure 8: Pairwise Hα flux variations as a function of rest-frame timescale. Estimates from LRDs are shown in red/purple, and BLAGNs are shown in blue. Note that these individual flux variations are error-inflated. The MAD-scaled traditional structure function (Eqn. 2) for the SDSS-RM comparison sample is shown as open gray circles and a dashed gray line. Bootstrapped uncertainties are shown shaded in light gray, bu… view at source ↗
Figure 9
Figure 9. Figure 9: Same as [PITH_FULL_IMAGE:figures/full_fig_p015_9.png] view at source ↗
Figure 10
Figure 10. Figure 10: An overview of the cool LRD NX7607 (z = 3.2). Top: The processed MSA prism spectra for each observed epoch. Prominent emission lines are indicated with vertical lines, and the Balmer break is shown as a dashed line. Bottom: Normalized emission line profiles for several emission line complexes. would resemble SDSS-RM or SEAMBH variability; cor￾relations between Hα and UV/optical continuum emis￾sion complic… view at source ↗

discussion (0)

Sign in with ORCID, Apple, or X to comment. Anyone can read and Pith papers without signing in.

Reference graph

Works this paper leans on

146 extracted references · 8 canonical work pages · 2 internal anchors

  1. [1]

    L., Yuan, W., Zhou, H

    Ai, Y. L., Yuan, W., Zhou, H. Y., et al. 2010, ApJL, 716, L31, doi: 10.1088/2041-8205/716/1/L31

    work page doi:10.1088/2041-8205/716/1/l31 2010

  2. [2]

    B., Casey, C

    Akins, H. B., Casey, C. M., Lambrides, E., et al. 2025, The Astrophysical Journal, 991, 37, doi: 10.3847/1538-4357/ade984

    doi:10.3847/1538-4357/ade984 2025

  3. [3]

    T., Bogd´ an,´A., Kov´ acs, O

    Ananna, T. T., Bogd´ an,´A., Kov´ acs, O. E., Natarajan, P., & Hickox, R. C. 2024, The Astrophysical Journal Letters, 969, L18, doi: 10.3847/2041-8213/ad5669

    doi:10.3847/2041-8213/ad5669 2024

  4. [4]

    Asada, Y., Inayoshi, K., Fei, Q., Fujimoto, S., & Willott, C. 2026, Origins of the UV Continuum and Balmer Emission Lines in Little Red Dots: Observational Validation of Dense Gas Envelope Models Enshrouding the AGN, arXiv Astropy Collaboration, Robitaille, T. P., Tollerud, E. J., et al. 2013, A&A, 558, A33, doi: 10.1051/0004-6361/201322068 Astropy Collab...

    doi:10.1051/0004-6361/201322068 2026

  5. [5]

    G., Kocevski, D

    Barro, G., P´ erez-Gonz´ alez, P. G., Kocevski, D. D., et al. 2024, The Astrophysical Journal, 963, 128, doi: 10.3847/1538-4357/ad167e

    doi:10.3847/1538-4357/ad167e 2024

  6. [6]

    C., & Dexter, J

    Begelman, M. C., & Dexter, J. 2026, The Astrophysical Journal, 996, 48, doi: 10.3847/1538-4357/ae274a

    doi:10.3847/1538-4357/ae274a 2026

  7. [7]

    C., Kulkarni, S

    Bellm, E. C., Kulkarni, S. R., Graham, M. J., et al. 2019, PASP, 131, 018002, doi: 10.1088/1538-3873/aaecbe

    doi:10.1088/1538-3873/aaecbe 2019

  8. [8]

    C., Denney, K

    Bentz, M. C., Denney, K. D., Grier, C. J., et al. 2013, ApJ, 767, 149, doi: 10.1088/0004-637X/767/2/149

    doi:10.1088/0004-637x/767/2/149 2013

  9. [9]

    D., & McKee, C

    Blandford, R. D., & McKee, C. F. 1982, The Astrophysical Journal, 255, 419, doi: 10.1086/159843

    doi:10.1086/159843 1982

  10. [10]

    2023, msaexp: NIRSpec analyis tools, 0.6.17 Zenodo, doi: 10.5281/zenodo.8319596

    Brammer, G. 2023, msaexp: NIRSpec analyis tools, 0.6.17 Zenodo, doi: 10.5281/zenodo.8319596

    doi:10.5281/zenodo.8319596 2023

  11. [11]

    2026, arXiv e-prints, arXiv:2601.22214, doi: 10.48550/arXiv.2601.22214

    Brazzini, M., D’Eugenio, F., Maiolino, R., et al. 2026, arXiv e-prints, arXiv:2601.22214, doi: 10.48550/arXiv.2601.22214

    doi:10.48550/arxiv.2601.22214 2026

  12. [12]

    C., Trump, J

    Brooks, M., Simons, R. C., Trump, J. R., et al. 2024, Here There Be (Dusty) Monsters: High Redshift AGN Are Dustier Than Their Hosts, arXiv, doi: 10.48550/arXiv.2410.07340

    Pith/arXiv arXiv doi:10.48550/arxiv.2410.07340 2024

  13. [13]

    R., Simons, R

    Brooks, M., Trump, J. R., Simons, R. C., et al. 2025, Beyond the Monsters: A More Complete Census of Black Hole Activity at Cosmic Dawn, arXiv, doi: 10.48550/arXiv.2511.19609

    doi:10.48550/arxiv.2511.19609 2025

  14. [14]

    J., Shen, Y., Liu, X., et al

    Burke, C. J., Shen, Y., Liu, X., et al. 2023, Monthly Notices of the Royal Astronomical Society, 518, 1880, doi: 10.1093/mnras/stac2478

    doi:10.1093/mnras/stac2478 2023

  15. [15]

    J., Stone, Z., Shen, Y., & Jiang, Y.-F

    Burke, C. J., Stone, Z., Shen, Y., & Jiang, Y.-F. 2026, ApJ, 1004, 16, doi: 10.3847/1538-4357/ae6b89

    work page doi:10.3847/1538-4357/ae6b89 2026

  16. [16]

    J., Shen, Y., Blaes, O., et al

    Burke, C. J., Shen, Y., Blaes, O., et al. 2021, Science, 373, 789, doi: 10.1126/science.abg9933

    doi:10.1126/science.abg9933 2021

  17. [17]

    C., et al

    Calzetti, D., Armus, L., Bohlin, R. C., et al. 2000, ApJ, 533, 682, doi: 10.1086/308692

    doi:10.1086/308692 2000

  18. [18]

    B., Perna, R., et al

    Cantiello, M., Hassan, J. B., Perna, R., et al. 2025, Pulsational Instability of Quasi-Stars: Interpreting the Variability of Little Red Dots, arXiv, doi: 10.48550/arXiv.2512.17997

    doi:10.48550/arxiv.2512.17997 2025

  19. [19]

    C., Begley, R., McLeod, D

    Carnall, A. C., Begley, R., McLeod, D. J., et al. 2023, Monthly Notices of the Royal Astronomical Society: Letters, 518, L45, doi: 10.1093/mnrasl/slac136

    doi:10.1093/mnrasl/slac136 2023

  20. [20]

    M., Akins, H

    Casey, C. M., Akins, H. B., Finkelstein, S. L., et al. 2025, The Astrophysical Journal, 990, L61, doi: 10.3847/2041-8213/adfa91

    doi:10.3847/2041-8213/adfa91 2025

  21. [21]

    A Population of Little Red Dot-like Quasars in SDSS

    Casey, Q. O., Hickox, R. C., Cleri, N. J., et al. 2026, arXiv e-prints, arXiv:2606.26098, doi: 10.48550/arXiv.2606.26098 21

    work page internal anchor Pith review Pith/arXiv arXiv doi:10.48550/arxiv.2606.26098 2026

  22. [22]

    2025, Monthly Notices of the Royal Astronomical Society, doi: 10.1093/mnras/staf2131

    Chang, S.-J., Gronke, M., Matthee, J., & Mason, C. 2025, Monthly Notices of the Royal Astronomical Society, doi: 10.1093/mnras/staf2131

    doi:10.1093/mnras/staf2131 2025

  23. [23]

    C., Li, R., & Zhuang, M.-Y

    Chen, C.-H., Ho, L. C., Li, R., & Zhuang, M.-Y. 2025, The Astrophysical Journal, 983, 60, doi: 10.3847/1538-4357/ada93a

    doi:10.3847/1538-4357/ada93a 2025

  24. [24]

    C., et al

    Chen, C.-H., Shangguan, J., Ho, L. C., et al. 2026, arXiv e-prints, arXiv:2606.04711, doi: 10.48550/arXiv.2606.04711

    Pith/arXiv arXiv doi:10.48550/arxiv.2606.04711 2026

  25. [25]

    Chen, K., Li, Z., Inayoshi, K., & Ho, L. C. 2025, ApJL, 994, L42, doi: 10.3847/2041-8213/ae1955 de Graaff, A., Rix, H.-W., Carniani, S., et al. 2024, A&A, 684, A87, doi: 10.1051/0004-6361/202347755 de Graaff, A., Rix, H.-W., Naidu, R. P., et al. 2025, Astronomy & Astrophysics, 701, A168, doi: 10.1051/0004-6361/202554681 de Graaff, A., Hviding, R. E., Naid...

    doi:10.48550/arxiv.2511.21820 2025

  26. [26]

    2025, A&A, 704, A313, doi: 10.1051/0004-6361/202557164 DESI Collaboration, Abdul Karim, M., Adame, A

    Delvecchio, I., Daddi, E., Magnelli, B., et al. 2025, A&A, 704, A313, doi: 10.1051/0004-6361/202557164 DESI Collaboration, Abdul Karim, M., Adame, A. G., et al. 2026, AJ, 171, 285, doi: 10.3847/1538-3881/ae4c43 D’Eugenio, F., Nelson, E., Ji, X., et al. 2025, arXiv e-prints, arXiv:2510.00101, doi: 10.48550/arXiv.2510.00101 D’Eugenio, F., Juodˇ zbalis, I., ...

    doi:10.48550/arxiv.2510.00101 2025

  27. [27]

    2016, ApJ, 825, 126, doi: 10.3847/0004-637X/825/2/126

    Du, P., Lu, K.-X., Zhang, Z.-X., et al. 2016, ApJ, 825, 126, doi: 10.3847/0004-637X/825/2/126

    doi:10.3847/0004-637x/825/2/126 2016

  28. [28]

    2018, ApJ, 856, 6, doi: 10.3847/1538-4357/aaae6b

    Du, P., Zhang, Z.-X., Wang, K., et al. 2018, ApJ, 856, 6, doi: 10.3847/1538-4357/aaae6b

    doi:10.3847/1538-4357/aaae6b 2018

  29. [29]

    W., Lang, D., & Goodman, J

    Foreman-Mackey, D., Hogg, D. W., Lang, D., & Goodman, J. 2013, PASP, 125, 306, doi: 10.1086/670067

    doi:10.1086/670067 2013

  30. [30]

    B., Trump, J

    Fries, L. B., Trump, J. R., Davis, M. C., et al. 2023, ApJ, 948, 5, doi: 10.3847/1538-4357/acbfb7

    work page doi:10.3847/1538-4357/acbfb7 2023

  31. [31]

    R., et al

    Fujimoto, S., Wang, B., Weaver, J. R., et al. 2024, The Astrophysical Journal, 977, 250, doi: 10.3847/1538-4357/ad9027

    doi:10.3847/1538-4357/ad9027 2024

  32. [32]

    J., Zitrin, A., Plat, A., et al

    Furtak, L. J., Zitrin, A., Plat, A., et al. 2023, The Astrophysical Journal, 952, 142, doi: 10.3847/1538-4357/acdc9d

    doi:10.3847/1538-4357/acdc9d 2023

  33. [33]

    J., Labb´ e, I., Zitrin, A., et al

    Furtak, L. J., Labb´ e, I., Zitrin, A., et al. 2024, Nature, 628, 57, doi: 10.1038/s41586-024-07184-8

    doi:10.1038/s41586-024-07184-8 2024

  34. [34]

    J., Secunda, A

    Furtak, L. J., Secunda, A. R., Greene, J. E., et al. 2025, Astronomy and Astrophysics, 698, A227, doi: 10.1051/0004-6361/202554110

    doi:10.1051/0004-6361/202554110 2025

  35. [35]

    M., & Benker, A

    Gaskell, C. M., & Benker, A. J. 2007, arXiv e-prints, arXiv:0711.1013, doi: 10.48550/arXiv.0711.1013

    Pith/arXiv arXiv doi:10.48550/arxiv.0711.1013 2007

  36. [36]

    Gordon, K. D. 2024, Journal of Open Source Software, 9, 7023, doi: 10.21105/joss.07023

    doi:10.21105/joss.07023 2024

  37. [37]

    D., Clayton, G

    Gordon, K. D., Clayton, G. C., Decleir, M., et al. 2023, The Astrophysical Journal, 950, 86, doi: 10.3847/1538-4357/accb59

    doi:10.3847/1538-4357/accb59 2023

  38. [38]

    D., Clayton, G

    Gordon, K. D., Clayton, G. C., Misselt, K. A., Landolt, A. U., & Wolff, M. J. 2003, The Astrophysical Journal, 594, 279, doi: 10.1086/376774

    doi:10.1086/376774 2003

  39. [39]

    D., Fitzpatrick, E

    Gordon, K. D., Fitzpatrick, E. L., Massa, D., et al. 2024, The Astrophysical Journal, 970, 51, doi: 10.3847/1538-4357/ad4be1

    doi:10.3847/1538-4357/ad4be1 2024

  40. [40]

    E., Labbe, I., Goulding, A

    Greene, J. E., Labbe, I., Goulding, A. D., et al. 2024, The Astrophysical Journal, 964, 39, doi: 10.3847/1538-4357/ad1e5f

    doi:10.3847/1538-4357/ad1e5f 2024

  41. [41]

    J., Pancoast, A., Barth, A

    Grier, C. J., Pancoast, A., Barth, A. J., et al. 2017, ApJ, 849, 146, doi: 10.3847/1538-4357/aa901b

    doi:10.3847/1538-4357/aa901b 2017

  42. [42]

    2023, The Astrophysical Journal, 959, 39, doi: 10.3847/1538-4357/ad029e

    Harikane, Y., Zhang, Y., Nakajima, K., et al. 2023, The Astrophysical Journal, 959, 39, doi: 10.3847/1538-4357/ad029e

    doi:10.3847/1538-4357/ad029e 2023

  43. [43]

    R., Millman, K

    Harris, C. R., Millman, K. J., van der Walt, S. J., et al. 2020, Nature, 585, 357, doi: 10.1038/s41586-020-2649-2

    doi:10.1038/s41586-020-2649-2 2020

  44. [44]

    2021, ApJS, 253, 20, doi: 10.3847/1538-4365/abd774

    Hu, C., Li, S.-S., Yang, S., et al. 2021, ApJS, 253, 20, doi: 10.3847/1538-4365/abd774

    doi:10.3847/1538-4365/abd774 2021

  45. [45]

    2022, ApJ, 934, 132, doi: 10.3847/1538-4357/ac75d8

    Hu, H., Inayoshi, K., Haiman, Z., Quataert, E., & Kuiper, R. 2022, ApJ, 934, 132, doi: 10.3847/1538-4357/ac75d8

    doi:10.3847/1538-4357/ac75d8 2022

  46. [46]

    Hunter, J. D. 2007, Computing in Science & Engineering, 9, 90, doi: 10.1109/MCSE.2007.55

    doi:10.1109/mcse.2007.55 2007

  47. [47]

    B., Crenshaw, D

    Hutchings, J. B., Crenshaw, D. M., Kraemer, S. B., et al. 2002, AJ, 124, 2543, doi: 10.1086/344080

    doi:10.1086/344080 2002

  48. [48]

    2024, ApJL, 973, L49, doi: 10.3847/2041-8213/ad74e2

    Inayoshi, K., & Ichikawa, K. 2024, ApJL, 973, L49, doi: 10.3847/2041-8213/ad74e2

    doi:10.3847/2041-8213/ad74e2 2024

  49. [49]

    S., & Noda, H

    Inayoshi, K., Kimura, S. S., & Noda, H. 2025, Publications of the Astronomical Society of Japan, 77, 811, doi: 10.1093/pasj/psaf050

    doi:10.1093/pasj/psaf050 2025

  50. [50]

    2025, Monthly Notices of the Royal Astronomical Society, 544, 3900, doi: 10.1093/mnras/staf1867

    Ji, X., Maiolino, R., ¨Ubler, H., et al. 2025, Monthly Notices of the Royal Astronomical Society, 544, 3900, doi: 10.1093/mnras/staf1867

    doi:10.1093/mnras/staf1867 2025

  51. [51]

    2026, Monthly Notices of the Royal Astronomical Society, 545, staf2235, doi: 10.1093/mnras/staf2235

    Ji, X., D’Eugenio, F., Juodˇ zbalis, I., et al. 2026, Monthly Notices of the Royal Astronomical Society, 545, staf2235, doi: 10.1093/mnras/staf2235

    doi:10.1093/mnras/staf2235 2026

  52. [52]

    M., & Davis, S

    Jiang, Y.-F., Stone, J. M., & Davis, S. W. 2014, ApJ, 796, 106, doi: 10.1088/0004-637X/796/2/106 Juodˇ zbalis, I., Maiolino, R., Baker, W. M., et al. 2026, MNRAS, 546, stag086, doi: 10.1093/mnras/stag086 Juodˇ zbalis, I., Ji, X., Maiolino, R., et al. 2024, Monthly Notices of the Royal Astronomical Society, 535, 853, doi: 10.1093/mnras/stae2367 22

    doi:10.1088/0004-637x/796/2/106 2014

  53. [53]

    C., Bechtold, J., & Siemiginowska, A

    Kelly, B. C., Bechtold, J., & Siemiginowska, A. 2009, ApJ, 698, 895, doi: 10.1088/0004-637X/698/1/895

    doi:10.1088/0004-637x/698/1/895 2009

  54. [54]

    C., Becker, A

    Kelly, B. C., Becker, A. C., Sobolewska, M., Siemiginowska, A., & Uttley, P. 2014, ApJ, 788, 33, doi: 10.1088/0004-637X/788/1/33

    doi:10.1088/0004-637x/788/1/33 2014

  55. [55]

    Kido, D., Ioka, K., Hotokezaka, K., Inayoshi, K., & Irwin, C. M. 2025, Monthly Notices of the Royal Astronomical Society, 544, 3407, doi: 10.1093/mnras/staf1898

    doi:10.1093/mnras/staf1898 2025

  56. [56]

    2010, ApJ, 724, 386, doi: 10.1088/0004-637X/724/1/386

    Kim, D., Im, M., & Kim, M. 2010, ApJ, 724, 386, doi: 10.1088/0004-637X/724/1/386

    doi:10.1088/0004-637x/724/1/386 2010

  57. [57]

    D., Onoue, M., Inayoshi, K., et al

    Kocevski, D. D., Onoue, M., Inayoshi, K., et al. 2023, The Astrophysical Journal, 954, L4, doi: 10.3847/2041-8213/ace5a0

    doi:10.3847/2041-8213/ace5a0 2023

  58. [58]

    D., Finkelstein, S

    Kocevski, D. D., Finkelstein, S. L., Barro, G., et al. 2025, The Astrophysical Journal, 986, 126, doi: 10.3847/1538-4357/adbc7d

    doi:10.3847/1538-4357/adbc7d 2025

  59. [59]

    2023, The Astrophysical Journal, 957, L7, doi: 10.3847/2041-8213/ad037a

    Kokorev, V., Fujimoto, S., Labbe, I., et al. 2023, The Astrophysical Journal, 957, L7, doi: 10.3847/2041-8213/ad037a

    doi:10.3847/2041-8213/ad037a 2023

  60. [60]

    I., Greene, J

    Kokorev, V., Caputi, K. I., Greene, J. E., et al. 2024, The Astrophysical Journal, 968, 38, doi: 10.3847/1538-4357/ad4265

    doi:10.3847/1538-4357/ad4265 2024

  61. [61]

    P., et al

    Kokorev, V., Chisholm, J., Naidu, R. P., et al. 2025, The Deepest GLIMPSE of a Dense Gas Cocoon Enshrouding a Little Red Dot, arXiv, doi: 10.48550/arXiv.2511.07515

    doi:10.48550/arxiv.2511.07515 2025

  62. [62]

    2024, MNRAS, 529, 2131, doi: 10.1093/mnras/stae515

    Kokubo, M. 2024, MNRAS, 529, 2131, doi: 10.1093/mnras/stae515

    doi:10.1093/mnras/stae515 2024

  63. [63]

    2025, The Astrophysical Journal, 995, 24, doi: 10.3847/1538-4357/ae119e Koz lowski, S

    Kokubo, M., & Harikane, Y. 2025, The Astrophysical Journal, 995, 24, doi: 10.3847/1538-4357/ae119e Koz lowski, S. 2016, ApJ, 826, 118, doi: 10.3847/0004-637X/826/2/118

    doi:10.3847/1538-4357/ae119e 2025

  64. [64]

    Kwan, J., & Krolik, J. H. 1981, ApJ, 250, 478, doi: 10.1086/159395 Labb´ e, I., van Dokkum, P., Nelson, E., et al. 2023, Nature, 616, 266, doi: 10.1038/s41586-023-05786-2

    doi:10.1086/159395 1981

  65. [65]

    E., Matthee, J., et al

    Labbe, I., Greene, J. E., Matthee, J., et al. 2024, An Unambiguous AGN and a Balmer Break in an Ultraluminous Little Red Dot at Z=4.47 from Ultradeep UNCOVER and All the Little Things Spectroscopy, arXiv, doi: 10.48550/arXiv.2412.04557

    Pith/arXiv arXiv doi:10.48550/arxiv.2412.04557 2024

  66. [66]

    E., Bezanson, R., et al

    Labbe, I., Greene, J. E., Bezanson, R., et al. 2025, The Astrophysical Journal, 978, 92, doi: 10.3847/1538-4357/ad3551

    doi:10.3847/1538-4357/ad3551 2025

  67. [67]

    K., Pitrou, A., & Seibert, S

    Lam, S. K., Pitrou, A., & Seibert, S. 2015, in Proceedings of the Second Workshop on the LL VM Compiler Infrastructure in HPC, LL VM ’15 (New York, NY, USA: Association for Computing Machinery), 1–6, doi: 10.1145/2833157.2833162

    arXiv 2015

  68. [68]

    Lambrides, E., Garofali, K., Larson, R., et al. 2024, The Case for Super-Eddington Accretion: Connecting Weak X-ray and UV Line Emission in JWST Broad-Line AGN During the First Gyr of Cosmic Time, arXiv, doi: 10.48550/arXiv.2409.13047

    Pith/arXiv arXiv doi:10.48550/arxiv.2409.13047 2024

  69. [69]

    A., Larson, R

    Lambrides, E., Hutchison, T. A., Larson, R. L., et al. 2026, arXiv e-prints, arXiv:2604.25991, doi: 10.48550/arXiv.2604.25991

    Pith/arXiv arXiv doi:10.48550/arxiv.2604.25991 2026

  70. [70]

    2017, MNRAS, 467, 540, doi: 10.1093/mnras/stx055

    Lamperti, I., Koss, M., Trakhtenbrot, B., et al. 2017, MNRAS, 467, 540, doi: 10.1093/mnras/stx055

    doi:10.1093/mnras/stx055 2017

  71. [71]

    C., Ward, M

    Landt, H., Bentz, M. C., Ward, M. J., et al. 2008, ApJS, 174, 282, doi: 10.1086/522373

    doi:10.1086/522373 2008

  72. [72]

    L., Finkelstein, S

    Larson, R. L., Finkelstein, S. L., Kocevski, D. D., et al. 2023, The Astrophysical Journal, 953, L29, doi: 10.3847/2041-8213/ace619

    doi:10.3847/2041-8213/ace619 2023

  73. [73]

    2026, ApJ, 1005, 150, doi: 10.3847/1538-4357/ae74c6

    Lin, R., Zheng, Z.-Y., Wang, J., et al. 2026, ApJ, 1005, 150, doi: 10.3847/1538-4357/ae74c6

    work page doi:10.3847/1538-4357/ae74c6 2026

  74. [74]

    2026, The Astrophysical Journal, 996, 93, doi: 10.3847/1538-4357/ae1b9b

    Lin, X., Fan, X., Wang, F., et al. 2026, The Astrophysical Journal, 996, 93, doi: 10.3847/1538-4357/ae1b9b

    doi:10.3847/1538-4357/ae1b9b 2026

  75. [75]

    2026, arXiv e-prints, arXiv:2605.21574, doi: 10.48550/arXiv.2605.21574

    Lin, X., Fan, X., Cai, Z., et al. 2026, arXiv e-prints, arXiv:2605.21574, doi: 10.48550/arXiv.2605.21574

    Pith/arXiv arXiv doi:10.48550/arxiv.2605.21574 2026

  76. [76]

    E., & Ma, Y

    Liu, H., Jiang, Y.-F., Quataert, E., Greene, J. E., & Ma, Y. 2025, The Astrophysical Journal, 994, 113, doi: 10.3847/1538-4357/ae0c19

    doi:10.3847/1538-4357/ae0c19 2025

  77. [77]

    Liu, J.-R., Feng, H., & Ho, L. C. 2026, arXiv e-prints, arXiv:2607.17448. https://arxiv.org/abs/2607.17448

    Pith/arXiv arXiv 2026

  78. [78]

    P., Secunda, A., et al

    Liu, Z., Naidu, R. P., Secunda, A., et al. 2026, arXiv e-prints, arXiv:2604.13000, doi: 10.48550/arXiv.2604.13000

    Pith/arXiv arXiv doi:10.48550/arxiv.2604.13000 2026

  79. [79]

    2019, ApJ, 877, 23, doi: 10.3847/1538-4357/ab16e8

    Lu, K.-X., Huang, Y.-K., Zhang, Z.-X., et al. 2019, ApJ, 877, 23, doi: 10.3847/1538-4357/ab16e8

    doi:10.3847/1538-4357/ab16e8 2019

  80. [80]

    E., Setton, D

    Ma, Y., Greene, J. E., Setton, D. J., et al. 2025, ApJ, 981, 191, doi: 10.3847/1538-4357/ada613

    doi:10.3847/1538-4357/ada613 2025

Showing first 80 references.

This paper was first reviewed by deepseek-v4-flash on August 4, 2026.