Pith. sign in

REVIEW 2 major objections 1 minor 3 cited by

High-resolution spectra detect Balmer absorption in four of ten Little Red Dots, implying dense excited hydrogen is nearly ubiquitous.

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 · grok-4.3

2026-06-28 21:17 UTC pith:WGWAUQZY

load-bearing objection High-res NIRSpec data on 10 LRDs gives first detections for several objects plus velocity and EW numbers, but the 4/10 rate does not securely support near-ubiquitous n=2 hydrogen. the 2 major comments →

arxiv 2606.00258 v1 pith:WGWAUQZY submitted 2026-05-29 astro-ph.GA

OCEANS of Absorption: High-resolution NIRSpec Spectroscopy Reveals Diverse Balmer-line Absorption in Little Red Dots

Kelcey Davis , Madisyn Brooks , Raymond C. Simons , Jonathan R. Trump , Guillermo Barro , Pablo Arrabal Haro , Bren E. Backhaus , Nikko J. Cleri
show 19 more authors
Alexander de la Vega Steven L. Finkelstein Mauro Giavalisco Norman A. Grogin Michaela Hirschmann Taylor A. Hutchison Dale Kocevski Anton M. Koekemoer Erini Lambrides Mario Llerena Ray A. Lucas Madeline A. Marshall Elizabeth J. McGrath Casey Papovich Aidan Starrs Anthony J. Taylor Phoebe R. Upton Sanderbeck Xin Wang Stijn Wuyts
This is my paper
classification astro-ph.GA
keywords Little Red DotsBalmer absorptionNIRSpec spectroscopyhigh-redshift galaxiesJWSThydrogen absorptionactive galactic nucleigalaxy spectra
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.

The work presents high-resolution NIRSpec spectra for ten Little Red Dots at redshifts 3 to 7. Four show clear Balmer-line absorption, a higher fraction than lower-resolution surveys, with blue-shifted velocities and typical equivalent widths around 5 Angstroms. Most objects also fit Ha profiles that include exponential wings. The authors model the absorption with radially distributed partial-covering gas often near the broad-line regions and with a velocity gradient from inflow close in to outflow at larger radii. This pattern, together with strong Balmer breaks, leads to the conclusion that dense excited n=2 hydrogen is common across the population.

Core claim

High-resolution follow-up of ten LRDs finds Balmer-line absorption in four cases, with absorbers blue-shifted by a median of 49 km/s and equivalent widths around 5.3 Angstroms; the diversity is explained by a radial distribution of partial-covering absorbing gas co-located near broad-line regions plus a velocity gradient of inflow near the center and outflow farther out, implying near-ubiquitous dense excited n=2 hydrogen.

What carries the argument

Radial distribution of partial-covering absorbing gas with velocity gradients from inflow close in to outflow farther out, which reproduces the range of observed absorption properties and line profiles.

Load-bearing premise

The ten LRDs form a representative sample and the high-resolution spectra contain no significant artifacts or line blending that could mimic or hide absorption.

What would settle it

A larger sample observed at comparable resolution showing absorption in substantially fewer than four out of ten LRDs would undermine the claim of near-ubiquitous dense excited hydrogen.

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

If this is right

  • Absorption detection rate rises with spectral resolution compared with earlier lower-resolution surveys.
  • Absorbing gas is frequently located near the broad-line emission regions.
  • Some LRDs show statistically significant velocity offsets between Ha and Hb absorption.
  • Most LRDs are better described by Ha profiles that include exponential wings.
  • The combination of absorption features and Balmer breaks indicates excited hydrogen is common.

Where Pith is reading between the lines

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

  • The same absorption signature could appear in other compact high-redshift sources once observed at matching resolution.
  • Larger samples could test whether absorption strength tracks other LRD traits such as UV-to-optical color.
  • The radial gas model makes specific predictions for line shapes that higher-resolution data could check.
  • Absorption may need to be accounted for when using emission-line ratios to diagnose the central power source.

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

2 major / 1 minor

Summary. The manuscript presents high-resolution NIRSpec spectroscopy from the OCEANS program of 10 Little Red Dots (LRDs) with Hα coverage at 3<z<7 in the CEERS/EGS field. It reports Balmer-line absorption in 4 of the 10 targets (a higher rate than prior lower-resolution NIRSpec surveys), with the absorbers showing a median velocity offset of -49 km/s and equivalent width of 5.3 Å; 7 LRDs are best fit by Hα profiles with exponential wings. Trends are explored, one case of statistically significant Hα-Hβ absorption velocity offset is confirmed, and a qualitative model of radially distributed partial-covering absorbing gas (often co-located with broad-line regions, with inflow/outflow velocity gradients) is invoked to explain the observed diversity. The work concludes that the high occurrence of absorbing hydrogen, together with Balmer-break strengths, implies a near-ubiquitous presence of dense, excited n=2 hydrogen in LRDs.

Significance. If the sample is representative and the features are free of artifacts, the quantitative spectral measurements (4/10 detections, median offset -49 km/s, EW 5.3 Å) would indicate that dense excited hydrogen is common in LRDs, supplying an important observational constraint on their geometry and excitation conditions. The high-resolution data enabling new detections and the direct reporting of velocity and EW values from the spectra are strengths.

major comments (2)
  1. [Abstract] Abstract: the inference of a 'near-ubiquitous presence of dense, excited n=2 hydrogen' is extrapolated from a 4/10 detection rate (plus Balmer-break evidence) in a sample of 10 LRDs selected for Hα coverage at 3<z<7; no selection function, completeness estimate, or comparison of the observed subsample to the full LRD catalog is supplied, leaving the representativeness assumption untested and load-bearing for the ubiquity claim.
  2. [Abstract] Abstract: the reported median velocity offset (-49 km/s) and absorption equivalent width (5.3 Å) are stated for the absorbers, but it is unclear whether these statistics incorporate only the 4 detections or also upper limits from the 6 non-detections; this distinction is required to assess whether the values characterize the typical LRD population or only the detected subset.
minor comments (1)
  1. [Abstract] Abstract: the phrase 'Trends are explored to compare LRD absorption properties along the sequence of LRDs' does not define what sequence is intended or summarize the specific trends recovered.

Simulated Author's Rebuttal

2 responses · 0 unresolved

We thank the referee for their careful reading and constructive comments. We address each major comment below and agree that revisions to the abstract are needed for precision.

read point-by-point responses

  1. Referee: [Abstract] Abstract: the inference of a 'near-ubiquitous presence of dense, excited n=2 hydrogen' is extrapolated from a 4/10 detection rate (plus Balmer-break evidence) in a sample of 10 LRDs selected for Hα coverage at 3<z<7; no selection function, completeness estimate, or comparison of the observed subsample to the full LRD catalog is supplied, leaving the representativeness assumption untested and load-bearing for the ubiquity claim.

    Authors: We agree that the sample of 10 LRDs is a subset selected for Hα coverage from the OCEANS program in CEERS/EGS and lacks a formal selection function, completeness estimate, or direct comparison to the full LRD catalog. The near-ubiquitous inference combines the 4/10 detection rate with Balmer-break strengths seen more broadly. We will revise the abstract to qualify the claim as applying to this observed sample, note the absence of a statistical selection function, and add a brief discussion of sample limitations to avoid over-extrapolation. revision: yes

  2. Referee: [Abstract] Abstract: the reported median velocity offset (-49 km/s) and absorption equivalent width (5.3 Å) are stated for the absorbers, but it is unclear whether these statistics incorporate only the 4 detections or also upper limits from the 6 non-detections; this distinction is required to assess whether the values characterize the typical LRD population or only the detected subset.

    Authors: The reported medians (-49 km/s and 5.3 Å) are calculated solely from the four detected absorbers, consistent with the phrasing 'absorbers tend to be blue-shifted'. Upper limits from the six non-detections were not included. We will revise the abstract and methods to state this explicitly, removing any potential ambiguity about whether the values describe the full population or only the detected subset. revision: yes

Circularity Check

0 steps flagged

No circularity: direct spectroscopic measurements and qualitative model

full rationale

The paper reports empirical Balmer absorption detections (4/10 sources) and equivalent widths/velocity offsets from NIRSpec spectra, then offers a qualitative radial partial-covering gas model to organize the observed diversity. No equations, fitted parameters, or self-citations are used to derive the reported quantities from the model itself; the measurements stand as independent data. The central claim of high occurrence is a direct count from the sample rather than a constructed prediction, making the derivation self-contained.

Axiom & Free-Parameter Ledger

2 free parameters · 0 axioms · 0 invented entities

The work rests on standard assumptions of spectroscopic line identification and Gaussian/exponential profile fitting; the physical model introduces no new particles or forces but invokes a radial gas distribution whose parameters are adjusted to match the observed line shapes.

free parameters (2)
  • median velocity offset = -49 km/s
    Measured from the absorption features across the sample
  • absorption equivalent width = 5.3 Angstroms
    Measured from the absorption features across the sample

pith-pipeline@v0.9.1-grok · 5988 in / 1236 out tokens · 29644 ms · 2026-06-28T21:17:40.710155+00:00 · methodology

0 comments
read the original abstract

The ``Little Red Dots' (LRDs) that appeared in JWST deep field images have been the subject of significant study since their discovery. In this work, we present high-resolution follow-up spectroscopy from the OCEANS program of 10 LRDs with Ha coverage at 3<z<7 in the CEERS/EGS field. We find Balmer-line absorption in 4 of these LRDs, a detection rate higher than the fractions reported in lower-resolution NIRSpec surveys. All of the absorbers are presented in high-resolution for the first time here and two have Balmer-line absorption detected for the first time. Of the 10 LRDs, 7 are best fit by Ha profiles with exponential wings. We find that absorbers tend to be blue-shifted with a median velocity offset of (-49 km/s) and absorption equivalent width of 5.3 Angstroms. Trends are explored to compare LRD absorption properties along the sequence of LRDs. We confirm an LRD with statistically significant absorption velocity offsets between Ha and Hb. The diversity of absorption properties can be effectively explained by a model with a radial distribution of partial-covering absorbing gas that is often co-located near the broad-line emission regions, along with a radial gradient of close inflow and distant outflow velocities for the absorbing gas. We present other interesting LRDs, including an outflow-dominated LRD and an LRD with relatively blue UV-to-optical colors but clear Balmer-line absorption. This high occurrence of absorbing hydrogen in LRDs, evident by both the Balmer-line absorption features and Balmer break strengths, implies a near-ubiquitous presence of dense, excited n=2 hydrogen.

Figures

Figures reproduced from arXiv: 2606.00258 by Aidan Starrs, Alexander de la Vega, Anthony J. Taylor, Anton M. Koekemoer, Bren E. Backhaus, Casey Papovich, Dale Kocevski, Elizabeth J. McGrath, Erini Lambrides, Guillermo Barro, Jonathan R. Trump, Kelcey Davis, Madeline A. Marshall, Madisyn Brooks, Mario Llerena, Mauro Giavalisco, Michaela Hirschmann, Nikko J. Cleri, Norman A. Grogin, Pablo Arrabal Haro, Phoebe R. Upton Sanderbeck, Ray A. Lucas, Raymond C. Simons, Steven L. Finkelstein, Stijn Wuyts, Taylor A. Hutchison, Xin Wang.

Figure 1
Figure 1. Figure 1: The OCEANS LRD sample in color-color space. All OCEANS targets are shown in solid light blue, OCEANS LRDs with broad Hα emission are shown as coral circles, and OCEANS LRDs with broad Balmer emission and absorption features are indicated with red stars. Blue circles indicate OCEANS sources with LRD colors that did not pass the compactness selection in [PITH_FULL_IMAGE:figures/full_fig_p005_1.png] view at source ↗
Figure 3
Figure 3. Figure 3: Hα ∆BIC by source for the OCEANS LRD set. Each possible combination of fit parameters is listed in the legend and assigned a unique marker. The ∆BIC is plotted relative to the minimized ∆BIC which best fit each source with the best-fit ∆BIC plotted at 0. Gauss is short for Gaussian only (no exponential line wings), Exp indicates an exponential convolved with a Gaussian was the best fit. Offset Gauss indica… view at source ↗
Figure 4
Figure 4. Figure 4: LRDs with Hα absorption features from OCEANS. Each row in the figure represents a single source in OCEANS. First column insets are Hβ, second are [Oiii]λ4960,5008, and third are Hα. The OCEANS spectrum is plotted in black and error is plotted as the light blue shaded region. Each inset has the total fit that gives the preferred ∆BIC described in Section 2. Narrow Hα is plotted with a light blue dotted line… view at source ↗
Figure 5
Figure 5. Figure 5: LRDs with broad Hα emission and no absorption from OCEANS. Each row in the figure represents a single source in OCEANS. First column insets are Hβ, second are [Oiii]λ4960,5008, and third are Hα.. The OCEANS spectrum is plotted in black and error is plotted as the light blue shaded region. Each inset has the total fit that gives the preferred ∆BIC described in Section 2. Narrow Hα is plotted with a light bl… view at source ↗
Figure 6
Figure 6. Figure 6: G395M (RUBIES) and G395H (OCEANS) cover￾age for a sources with an absorption feature only recovered in high-resolution spectroscopy. High-resolution OCEANS 102364 spectrum in black, medium-resolution RUBIES 28489 spectrum in red, and the OCEANS spectrum degraded to the RUBIES resolution for an Hα line at z = 4.54 in blue. 100 300 1000 3000 Survey Spectral Resolution (R) 0% 20% 40% 60% 80% 100% Percentage o… view at source ↗
Figure 7
Figure 7. Figure 7: The fraction of LRDs with Balmer absorption in various surveys as a function of spectral resolution. At prism resolution (R ∼ 100), LRD surveys do not recover absorption (Greene et al. (2024), 0/17). Of the surveys with medium-resolution (R ∼ 1000) coverage (Taylor et al. (2025b) (4/21), Matthee et al. (2024) (2/20), and Kocevski et al. (2025) (3/17)), typically 10-20% of LRDs have Balmer line absorption. … view at source ↗
Figure 9
Figure 9. Figure 9: The velocity offset and rest frame EW of the Hα absorption in the OCEANS (red) and (Matthee et al. 2026) (blue) samples. High-resolution absorption detections (G395H and/or 235H) are marked with stars and medium￾resolution (G395M) detections are marked with squares. We find a median EW of 5.3 ˚A and a median velocity offset of −49 km s−1 . Population distributions are given along each axis. We note that OC… view at source ↗
Figure 10
Figure 10. Figure 10: Hα (black) and Hβ (red) line profiles for the OCEANS absorbing LRDs. Hβ is scaled to Hα peak flux for profile comparison. Two absorbers have recovered absorption in their Hβ line profiles (left two) and two do not (right two) but are consistent with low signal-to-noise observations of Hβ. OCEANS 20504 and 35829 were both observed in multiple MSA pointings (see the Appendix) and the spectra displayed here … view at source ↗
Figure 11
Figure 11. Figure 11: Cartoon of absorbing-medium locations for OCEANS 35829 and OCEANS 20504 which have absorption velocity offsets implying n=2 absorbing hydrogen is co-located with Hα and Hβ emission regions which are radially stratified. This source contrasts the implied location of the absorbing medium location for OCEANS 20504 which has absorption velocity offsets implying n=2 absorbing hydrogen is located primarily outs… view at source ↗
Figure 12
Figure 12. Figure 12: Absorption velocity offset from the systemic redshift (top row) and Absorption EW (bottom row) vs net-to-narrow emission (column 1), UV-to-Optical color (column 2), and Balmer break strength (column 3) for the OCEANS and Matthee et al. (2026) absorbing LRDs. OCEANS data (G395H and G235H) is represented by red stars, high resolution absorbers (G395H and/or 235H) from (Matthee et al. 2026) are represented b… view at source ↗

discussion (0)

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

Forward citations

Cited by 3 Pith papers

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

  1. The metallicities of little red dot host galaxies: LRDs are metal poor, but not pristine

    astro-ph.GA 2026-06 unverdicted novelty 7.0

    LRD host galaxies show average metallicity 0.08 Z_sun with narrow stable range, challenging pristine-gas formation models while ruling out typical local AGN.

  2. A Population of Little Red Dot-like Quasars in SDSS

    astro-ph.GA 2026-06 unverdicted novelty 7.0

    Defines a sample of ~1300 SDSS quasars as Local Red Dots matching LRD photometric colors at z~0.4-0.8, with a V-shaped subset showing Balmer absorption and [NeV] emission, and SEDs modeled as reddened AGN plus host ga...

  3. Little Red Dots as Intermediate Mass, Super-Eddington Engines: Insights from Type IIn Supernovae and The 1837-1856 Great Eruption of $\eta$ Carinae

    astro-ph.GA 2026-06 unverdicted novelty 6.0

    LRDs are reinterpreted as intermediate-mass super-Eddington systems with wind-driven pseudo-photospheres that explain their spectra and imply engine masses below 10^5 solar masses rather than overmassive black holes.

Reference graph

Works this paper leans on

54 extracted references · 54 canonical work pages · cited by 3 Pith papers · 5 internal anchors

  1. [1]

    2006, ApJ, 651, 84, doi: 10.1086/507438 Astropy Collaboration, Robitaille, T

    Aoki, K., Iwata, I., Ohta, K., et al. 2006, ApJ, 651, 84, doi: 10.1086/507438 Astropy Collaboration, Robitaille, T. P., Tollerud, E. J., et al. 2013, A&A, 558, A33, doi: 10.1051/0004-6361/201322068 18Davis et al. Astropy Collaboration, Price-Whelan, A. M., Sip˝ ocz, B. M., et al. 2018, AJ, 156, 123, doi: 10.3847/1538-3881/aabc4f Astropy Collaboration, Pri...

    work page doi:10.1086/507438 2006

  2. [2]

    B., Finkelstein, S

    Bagley, M. B., Finkelstein, S. L., Koekemoer, A. M., et al. 2023, ApJL, 946, L12, doi: 10.3847/2041-8213/acbb08

    work page doi:10.3847/2041-8213/acbb08 2023

  3. [3]

    arXiv e-prints , keywords =

    Barro, G., Perez-Gonzalez, P. G., Kocevski, D., et al. 2025, arXiv e-prints, arXiv:2512.15853, doi: 10.48550/arXiv.2512.15853

    work page doi:10.48550/arxiv.2512.15853 2025

  4. [4]

    G., Kocevski, D

    Barro, G., P´ erez-Gonz´ alez, P. G., Kocevski, D. D., et al. 2026, ApJ, 997, 48, doi: 10.3847/1538-4357/ae0704

    work page doi:10.3847/1538-4357/ae0704 2026

  5. [5]

    Nature Astronomy , keywords =

    Boylan-Kolchin, M. 2023, Nature Astronomy, 7, 731, doi: 10.1038/s41550-023-01937-7

    work page doi:10.1038/s41550-023-01937-7 2023

  6. [6]

    , keywords =

    Brooks, M., Simons, R. C., Trump, J. R., et al. 2025, ApJ, 986, 177, doi: 10.3847/1538-4357/addac4

    work page doi:10.3847/1538-4357/addac4 2025

  7. [7]

    2025, JWST Calibration Pipeline, Zenodo, doi: 10.5281/zenodo.16280965

    Bushouse, H., Eisenhamer, J., Dencheva, N., et al. 2025, JWST Calibration Pipeline, Zenodo, doi: 10.5281/zenodo.16280965

    work page doi:10.5281/zenodo.16280965 2025

  8. [8]

    R., et al

    Davis, K., Brooks, M., Trump, J. R., et al. 2026, arXiv e-prints, arXiv:2602.23310, doi: 10.48550/arXiv.2602.23310 de Graaff, A., Rix, H.-W., Naidu, R. P., et al. 2025a, A&A, 701, A168, doi: 10.1051/0004-6361/202554681 de Graaff, A., Brammer, G., Weibel, A., et al. 2025b, A&A, 697, A189, doi: 10.1051/0004-6361/202452186 de Graaff, A., Hviding, R. E., Naid...

    work page doi:10.48550/arxiv.2602.23310 2026

  9. [9]

    L., Leung, G

    Finkelstein, S. L., Leung, G. C. K., Bagley, M. B., et al. 2024, ApJL, 969, L2, doi: 10.3847/2041-8213/ad4495

    work page doi:10.3847/2041-8213/ad4495 2024

  10. [10]

    L., Bagley, M

    Finkelstein, S. L., Bagley, M. B., Arrabal Haro, P., et al. 2025, ApJL, 983, L4, doi: 10.3847/2041-8213/adbbd3

    work page doi:10.3847/2041-8213/adbbd3 2025

  11. [11]

    , keywords =

    Fries, L. B., Trump, J. R., Horne, K., et al. 2024, ApJ, 975, 239, doi: 10.3847/1538-4357/ad7c42

    work page doi:10.3847/1538-4357/ad7c42 2024

  12. [12]

    , keywords =

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

    work page doi:10.3847/1538-4357/ad1e5f 2024

  13. [13]

    A., Kocevski, D

    Grogin, N. A., Kocevski, D. D., Faber, S. M., et al. 2011, ApJS, 197, 35, doi: 10.1088/0067-0049/197/2/35

    work page doi:10.1088/0067-0049/197/2/35 2011

  14. [14]

    Hall, P. B. 2007, AJ, 133, 1271, doi: 10.1086/511272

    work page doi:10.1086/511272 2007

  15. [15]

    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

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

  16. [16]

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

    work page doi:10.1109/mcse.2007.55 2007

  17. [17]

    A., Larson, R

    Hutchison, T. A., Larson, R. L., Arrabal Haro, P., et al. 2025, arXiv e-prints, arXiv:2512.12509, doi: 10.48550/arXiv.2512.12509

    work page doi:10.48550/arxiv.2512.12509 2025

  18. [18]

    , keywords =

    Hviding, R. E., de Graaff, A., Miller, T. B., et al. 2025, A&A, 702, A57, doi: 10.1051/0004-6361/202555816

    work page doi:10.1051/0004-6361/202555816 2025

  19. [19]

    , keywords =

    Inayoshi, K., & Maiolino, R. 2025, ApJL, 980, L27, doi: 10.3847/2041-8213/adaebd

    work page doi:10.3847/2041-8213/adaebd 2025

  20. [20]

    , keywords =

    Ji, X., D’Eugenio, F., Juodˇ zbalis, I., et al. 2026, MNRAS, 545, staf2235, doi: 10.1093/mnras/staf2235 Juodˇ zbalis, I., Ji, X., Maiolino, R., et al. 2024, MNRAS, 535, 853, doi: 10.1093/mnras/stae2367

    work page doi:10.1093/mnras/staf2235 2026

  21. [21]

    , keywords =

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

    work page doi:10.3847/2041-8213/ace5a0 2023

  22. [22]

    D., Finkelstein, S

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

    work page doi:10.3847/1538-4357/adbc7d 2025

  23. [23]

    M., Faber, S

    Koekemoer, A. M., Faber, S. M., Ferguson, H. C., et al. 2011, ApJS, 197, 36, doi: 10.1088/0067-0049/197/2/36

    work page doi:10.1088/0067-0049/197/2/36 2011

  24. [24]

    , keywords =

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

    work page doi:10.3847/1538-4357/ad4265 2024

  25. [25]

    P., et al

    Kokorev, V., Chisholm, J., Naidu, R. P., et al. 2025, arXiv e-prints, arXiv:2511.07515, doi: 10.48550/arXiv.2511.07515

    work page doi:10.48550/arxiv.2511.07515 2025

  26. [26]

    2013, A&A, 549, A100, doi:10.1051/0004-6361/201219411

    Kollatschny, W., & Zetzl, M. 2013, A&A, 549, A100, doi: 10.1051/0004-6361/201219411

    work page doi:10.1051/0004-6361/201219411 2013

  27. [27]

    T., & Goad, M

    Korista, K. T., & Goad, M. R. 2004, ApJ, 606, 749, doi: 10.1086/383193 Labb´ e, I., van Dokkum, P., Nelson, E., et al. 2023, Nature, 616, 266, doi: 10.1038/s41586-023-05786-2

    work page doi:10.1086/383193 2004

  28. [28]

    arXiv e-prints , keywords =

    Lambrides, E., Larson, R., Hutchison, T., et al. 2025, arXiv e-prints, arXiv:2509.09607, doi: 10.48550/arXiv.2509.09607

    work page doi:10.48550/arxiv.2509.09607 2025

  29. [29]

    2006, ApJ, 643, 112, doi: 10.1086/502798

    Laor, A. 2006, ApJ, 643, 112, doi: 10.1086/502798

    work page doi:10.1086/502798 2006

  30. [30]

    2025, JWST Pipeline Notebooks, 1.0.0, Zenodo, doi: 10.5281/zenodo.15060584

    Law, D., Diaz, R., Sosey, M., et al. 2025, JWST Pipeline Notebooks, 1.0.0, Zenodo, doi: 10.5281/zenodo.15060584

    work page doi:10.5281/zenodo.15060584 2025

  31. [31]

    M., Gallagher, S

    Leighly, K. M., Gallagher, S. C., Choi, H., et al. 2025, ApJ, 993, 129, doi: 10.3847/1538-4357/ae04df

    work page doi:10.3847/1538-4357/ae04df 2025

  32. [32]

    M., Terndrup, D

    Leighly, K. M., Terndrup, D. M., Lucy, A. B., et al. 2019, ApJ, 879, 27, doi: 10.3847/1538-4357/ab212a

    work page doi:10.3847/1538-4357/ab212a 2019

  33. [33]

    , keywords =

    Ma, Y., Greene, J. E., Setton, D. J., et al. 2026, ApJ, 1000, 59, doi: 10.3847/1538-4357/ae4596

    work page doi:10.3847/1538-4357/ae4596 2026

  34. [34]

    Wings of little dots: Exponential broad lines from a stratified BLR

    Madau, P., Maiolino, R., Scholtz, J., & D’Eugenio, F. 2026, arXiv e-prints, arXiv:2604.04216, doi: 10.48550/arXiv.2604.04216

    work page internal anchor Pith review Pith/arXiv arXiv doi:10.48550/arxiv.2604.04216 2026

  35. [35]

    , keywords =

    Matthee, J., Naidu, R. P., Brammer, G., et al. 2024, ApJ, 963, 129, doi: 10.3847/1538-4357/ad2345 OCEANS of Absorption19

    work page doi:10.3847/1538-4357/ad2345 2024

  36. [36]

    2026, arXiv e-prints, arXiv:2603.17667

    Matthee, J., Torralba, A., Pezzulli, G., et al. 2026, arXiv e-prints, arXiv:2603.17667, doi: 10.48550/arXiv.2603.17667

    work page doi:10.48550/arxiv.2603.17667 2026

  37. [37]

    J., Finkelstein, S

    McGrath, E. J., Finkelstein, S. L., Barro, G., et al. 2026, The Astrophysical Journal Letters, 999, L6, doi: 10.3847/2041-8213/ae3da2

    work page doi:10.3847/2041-8213/ae3da2 2026

  38. [38]

    A "Black Hole Star" Reveals the Remarkable Gas-Enshrouded Hearts of the Little Red Dots

    Naidu, R. P., Matthee, J., Katz, H., et al. 2025, arXiv e-prints, arXiv:2503.16596, doi: 10.48550/arXiv.2503.16596

    work page internal anchor Pith review Pith/arXiv arXiv doi:10.48550/arxiv.2503.16596 2025

  39. [39]

    M., Ivezi´ c,ˇZ., & Elitzur, M

    Nenkova, M., Sirocky, M. M., Ivezi´ c,ˇZ., & Elitzur, M. 2008, ApJ, 685, 147, doi: 10.1086/590482

    work page doi:10.1086/590482 2008

  40. [40]

    Osterbrock, D. E. 1989, Astrophysics of gaseous nebulae and active galactic nuclei pandas development team, T. 2020, pandas-dev/pandas: Pandas, 1.3.1, Zenodo, doi: 10.5281/zenodo.3509134

    work page doi:10.5281/zenodo.3509134 1989

  41. [41]

    The Structure and Evolution of LRDs: Insights from JWST NIRSpec Medium and High Resolution Spectroscopy at $z\sim4$

    Pang, Y., Wang, X., Cheng, C., et al. 2026, arXiv e-prints, arXiv:2602.12548, doi: 10.48550/arXiv.2602.12548 Planck Collaboration, Aghanim, N., Akrami, Y., et al. 2020, A&A, 641, A6, doi: 10.1051/0004-6361/201833910

    work page internal anchor Pith review Pith/arXiv arXiv doi:10.48550/arxiv.2602.12548 2026

  42. [42]

    Beyond the Dot: an LRD-like nucleus at the Heart of an IR-Bright Galaxy and its implications for high-redshift LRDs

    Rinaldi, P., Rieke, G. H., Wu, Z., et al. 2025, arXiv e-prints, arXiv:2507.17738, doi: 10.48550/arXiv.2507.17738

    work page internal anchor Pith review Pith/arXiv arXiv doi:10.48550/arxiv.2507.17738 2025

  43. [43]

    , keywords =

    Rusakov, V., Watson, D., Nikopoulos, G. P., et al. 2026, Nature, 649, 574, doi: 10.1038/s41586-025-09900-4

    work page doi:10.1038/s41586-025-09900-4 2026

  44. [44]

    2016, ApJ, 819, 99, doi: 10.3847/0004-637X/819/2/99

    Shi, X., Zhou, H., Shu, X., et al. 2016, ApJ, 819, 99, doi: 10.3847/0004-637X/819/2/99

    work page doi:10.3847/0004-637x/819/2/99 2016

  45. [45]

    2017, ApJL, 843, L14, doi: 10.3847/2041-8213/aa725e

    Shi, X.-H., Pan, X., Zhang, S.-H., et al. 2017, ApJL, 843, L14, doi: 10.3847/2041-8213/aa725e

    work page doi:10.3847/2041-8213/aa725e 2017

  46. [46]

    SPURS: Evidence for Clumpy Neutral Envelopes and Ionized IGM Surrounding Little Red Dots in Abell 2744 from Ultra-Deep Rest-UV Spectroscopy

    Tang, M., Stark, D. P., Mason, C. A., et al. 2026, arXiv e-prints, arXiv:2604.03563, doi: 10.48550/arXiv.2604.03563

    work page internal anchor Pith review Pith/arXiv arXiv doi:10.48550/arxiv.2604.03563 2026

  47. [47]

    , keywords =

    Taylor, A. J., Kokorev, V., Kocevski, D. D., et al. 2025a, ApJL, 989, L7, doi: 10.3847/2041-8213/ade789

    work page doi:10.3847/2041-8213/ade789 2041

  48. [48]

    , keywords =

    Taylor, A. J., Finkelstein, S. L., Kocevski, D. D., et al. 2025b, ApJ, 986, 165, doi: 10.3847/1538-4357/add15b

    work page doi:10.3847/1538-4357/add15b

  49. [49]

    2025, arXiv e-prints, arXiv:2510.00103

    Torralba, A., Matthee, J., Pezzulli, G., et al. 2025, arXiv e-prints, arXiv:2510.00103, doi: 10.48550/arXiv.2510.00103

    work page doi:10.48550/arxiv.2510.00103 2025

  50. [50]

    E., & Bergeron, P

    Tremblay, P.-E., & Bergeron, P. 2009, ApJ, 696, 1755, doi: 10.1088/0004-637X/696/2/1755

    work page doi:10.1088/0004-637x/696/2/1755 2009

  51. [51]

    R., Hall, P

    Trump, J. R., Hall, P. B., Reichard, T. A., et al. 2006, ApJS, 165, 1, doi: 10.1086/503834 Villafa˜ na, L., Treu, T., Colleyn, L., et al. 2024, ApJ, 966, 106, doi: 10.3847/1538-4357/ad35cb

    work page doi:10.1086/503834 2006

  52. [52]

    E., et al

    Virtanen, P., Gommers, R., Oliphant, T. E., et al. 2020, Nature Methods, 17, 261, doi: 10.1038/s41592-019-0686-2

    work page doi:10.1038/s41592-019-0686-2 2020

  53. [53]

    , keywords =

    Wang, B., de Graaff, A., Davies, R. L., et al. 2025, ApJ, 984, 121, doi: 10.3847/1538-4357/adc1ca

    work page doi:10.3847/1538-4357/adc1ca 2025

  54. [54]

    Wang, J., & Xu, D. W. 2015, A&A, 573, A15, doi: 10.1051/0004-6361/201424848 Wes McKinney. 2010, in Proceedings of the 9th Python in Science Conference, ed. St´ efan van der Walt & Jarrod Millman, 56 – 61, doi: 10.25080/Majora-92bf1922-00a 20Davis et al. 6.APPENDIX We include additional information about our LRD population. Table 2 lists the OCEANS IDs and...

    work page doi:10.1051/0004-6361/201424848 2015