Pith. sign in

REVIEW 3 major objections 5 minor 15 cited by

A z=6.68 little red dot shows iron emission lines, including possible [FeVII], that point to an accreting supermassive black hole just 800 million years after the Big Bang.

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 · deepseek-v4-flash

2026-08-04 18:44 UTC pith:MZSDQT43

load-bearing objection A careful deep spectrum makes a credible AGN case for a z~6.7 LRD, but the marquee multiply-ionized-iron claim rests on a 4.5-sigma line whose [FeII] 19F alternative is not yet fully excluded. the 3 major comments →

arxiv 2509.09607 v1 pith:MZSDQT43 submitted 2025-09-11 astro-ph.GA

Discovery of Multiply Ionized Iron Emission Powered by an Active Galactic Nucleus in a z~7 Little Red Dot

Erini Lambrides , Rebecca Larson , Taylor Hutchison , Pablo Arrabal Haro , Bingjie Wang , Brian Welch , Dale D. Kocevski , Chris T. Richardson
show 45 more authors
Casey Papovich Jonathan R. Trump Sarah E. I. Bosman Jane R. Rigby Steven L. Finkelstein Guillermo Barro Jacqueline Antwi-Danso Arianna Long Anthony J. Taylor Jenna Cann Jeffrey McKaig Anton M. Koekemoer Nikko J. Cleri Hollis B. Akins Mic B. Bagley Danielle A. Berg Volker Bromm John Chisholm Katherine Chworowsky Sadie Coffin M. C. Cooper Olivia Cooper Isa Cox Mark Dickinson Henry C. Ferguson Maximilien Franco Jonathan P. Gardner Norman A. Grogin Michaela Hirschmann Marc Huertas-Company Intae Jung Jeyhan S. Kartaltepe Gourav P. Khullar Ray A. Lucas Elizabeth J. McGrath Alexa M. Morales Grace M. Olivier \'Oscar A. Ch\'avez Ortiz Pablo G. P\'erez-Gonz\'alez Norbert Pirzkal Rachel S. Somerville Brittany Vanderhoof Benjamin J. Weiner L. Y. Aaron Yung Jorge A. Zavala
This is my paper
classification astro-ph.GA
keywords little red dotsAGNcoronal linesiron emissionBalmer absorptionJWSThigh-redshift galaxiesz~7
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 argues that a deep JWST spectrum of a 'little red dot' galaxy at redshift 6.68 reveals the clearest direct evidence yet that at least some of these compact red sources are powered by accreting supermassive black holes. The key is a set of rare iron emission lines, especially a possible [FeVII] coronal line that requires ionizing photons above 99 eV—beyond what stars can produce. Combined with narrow Balmer absorption that only partially covers the broad-line region, the paper proposes that we are seeing unobscured sightlines from the accretion disk to gas at or beyond the broad-line gas, a geometry that would resolve several puzzling features of little red dots. If correct, this source demonstrates that some little red dots are genuine AGN seen through a patchy, dense absorber rather than dust-obscured star-forming galaxies.

Core claim

The paper reports the discovery of several rare iron emission features in the little red dot THRILS 46403 at z=6.68476, including a 4.5-sigma detection at 5160.3 Å that it interprets as the high-ionization coronal line [FeVII]λ5160 (ionization potential 99 eV). Alongside this, the spectrum shows broad Balmer emission with narrow absorption troughs in Hα and Hβ; the absorption equivalent-width ratio and trough depth indicate the absorber is only partially covering the broad-line region and the continuum source. The paper argues that the existence of [FeVII], together with extreme [OIII]λ4364/Hγ and elevated electron temperatures, strongly favors an accreting supermassive black hole as the cen

What carries the argument

The central object is the [FeVII]λ5160 coronal emission line, a high-ionization-potential (IP=99 eV) forbidden transition that essentially cannot be produced by stellar populations and therefore serves as a smoking gun for AGN activity. The argument also depends on the narrow Balmer absorption features (FWHM ~340 km/s, close to the [OIII] line width) and the demonstration that they only partially cover the broad-line region, placing the absorbing gas at or beyond the outer edge of the broad-line region rather than in a dense, fully covering shroud.

Load-bearing premise

The identification of the 5160.3 Å feature as [FeVII]λ5160 rather than the nearby rare forbidden [FeII]19F transition or Mg I b absorption is the load-bearing step; the feature is detected at only 4.5σ and the paper itself labels it 'possible'.

What would settle it

A higher-S/N rest-frame optical spectrum of THRILS 46403 that resolves the 5160 Å region and demonstrates that the feature cannot be separated from [FeII]19F or Mg Ib absorption, or that fails to show the expected flux ratio with [FeVII]λ6088 under plausible density/ionization conditions, would refute the AGN coronal-line interpretation.

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

If this is right

  • If [FeVII] is real, it would be the first robust coronal-line detection in a z>5 little red dot, breaking the pattern of non-detections and strengthening the AGN interpretation for at least a subset of the population.
  • The detection of multiple forbidden iron transitions at z~7 implies that iron was already abundant enough in this early galaxy to produce observable emission, constraining chemical enrichment timescales.
  • The partial-covering Balmer absorber scenario implies that some little red dots are not enshrouded by a uniform, dense screen but contain direct sightlines from the accretion disk to gas at intermediate radii, which would affect estimates of black hole masses and Eddington ratios derived from broad-line measurements.
  • The extreme [OIII]λ4364/Hγ ratio and the elevated O++ temperature support the presence of a very powerful ionizing source, and the paper argues that shock excitation alone cannot reproduce the observed ratios, further favoring an AGN.
  • If the geometry proposed here is typical, it would explain why little red dots often show broad Balmer lines but lack X-ray detections: the absorbing gas may be Compton-thin but dense enough to suppress soft X-rays while allowing optical coronal lines to escape.

Where Pith is reading between the lines

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

  • A natural extension not fully explored in the paper is that the same partial-covering geometry could explain the apparent Balmer break in many little red dots: a dense, cool, partially covering absorber would imprint a Balmer break without requiring an old stellar population.
  • The paper's interpretation predicts that deeper, higher-S/N spectra of THRILS 46403 should reveal the companion [FeVII]λ6088 line at a flux ratio consistent with continuum pumping, or else strengthen the case for an exotic excitation mechanism; this is a directly testable consequence.
  • If future surveys find similar [FeVII] features in other little red dots at z>5, the coronal-line 'smoking gun' could become a standard diagnostic, but the rarity of the 5160 Å feature relative to 6088 Å may complicate such searches and require careful modeling of FeII contamination.
  • The paper's emphasis on iron emission as a probe of gas near the dust sublimation radius suggests that, with sufficiently deep spectra, iron lines could serve as a distance indicator to the inner edge of the dusty torus in early-Universe AGN, analogous to local coronal-line studies.

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

3 major / 5 minor

Summary. The paper presents deep JWST/NIRSpec G395M spectroscopy of THRILS 46403, a Little Red Dot at z=6.68, and reports broad Balmer emission with narrow Balmer absorption, several weak iron emission features, auroral [OIII] and [NII] lines, and a 4.5σ emission line at 5160.3 Å interpreted as [FeVII] λ5160. From these the authors argue that this LRD hosts an accreting supermassive black hole with direct sightlines to gas at or beyond the broad-line region, and that the Balmer absorber has a small covering fraction. The paper includes tests of alternative identifications for the 5160 Å feature (Fe II 42 multiplet, [Fe II] 19F, Mg I b), a shock-model comparison, and a density/temperature analysis of the auroral lines.

Significance. If the [FeVII] identification holds, this would be the first detection of a multiply ionized iron coronal line in a Little Red Dot at z>5, providing a strong AGN signature and unique constraints on the geometry of the obscuring/absorbing gas. The paper is commendable for its deep 8.4-hour exposure, its explicit treatment of the Balmer absorption degeneracy, and its external tests against shock models and alternative line identifications. However, the central 'multiply ionized iron' claim rests on a single 4.5σ line, and the alternative [FeII] 19F identification is excluded only under an asymmetric set of model assumptions. The paper is honest in places—the abstract and conclusion call the [FeVII] detection 'possible'—but the title and the 'discovery' framing are stronger than the evidence currently supports.

major comments (3)
  1. [§5.4 and Figure 7] The test that excludes [FeII] 19F is not symmetric. In the middle panel of Figure 7, the [FeII]19F component has its velocity offset fixed to the other [FeII] lines and its FWHM fixed to the [OIII] value (342.6 km/s), while in the left panel the [FeVII] component is allowed a free FWHM (575 km/s). With such restricted freedom for [FeII]19F, the conclusion that an additional Gaussian at [FeVII] is required is not established. Please rerun the BADASS fits with [FeII]19F given the same free velocity and width as the [FeVII] component and compare the two models with a Bayesian evidence ratio or equivalent information criterion. Without this apples-to-apples comparison, the identification of the 5160 Å feature as [FeVII] remains ambiguous.
  2. [§2.3 and Table 2] The multiply-ionized iron claim rests on a single detection: [FeVII] λ5160 at 4.5σ. The partner transition [FeVII] λ6088, often the strongest [FeVII] line, is not detected. The paper invokes Lyα pumping/continuum variability (Ref. 81) to explain the anomalous ratio, but no quantitative model or calculation is presented for this source. The expected 6088/5160 ratio should be computed over the allowed density and ionization-parameter range (e.g., with Cloudy) and compared to the observed upper limit. Without such a consistency check, the line should be described as a candidate, and the title/abstract should be softened accordingly.
  3. [§2.3 and Table 2] The 'several rare iron transitions' are individually weak: three of the six iron features are reported at 3.0–3.4σ, and two are explicitly partial blends (Table 2 footnotes a, b). The [FeVII] identification is the only multiply-ionized iron line, so the strength of the 'discovery' claim is disproportionate to the statistical weight of the individual detections. A joint fit or a stacked analysis of all the iron features, with and without the 5160 Å line, would provide a more robust measure of whether the iron spectrum is detected as an ensemble.
minor comments (5)
  1. [§2.1] The text states 'assuming T_e = 10 K and n_e = 10^2 cm^-3'; the electron temperature is presumably 10^4 K, not 10 K. Please correct the typo.
  2. [Abstract] The abstract says 'a possible [FeVII] detections' (plural). Should be 'a possible [FeVII] detection'.
  3. [§5.1] There is a typo: 'In We use the default flux calibration...' should read 'We use the default flux calibration...'.
  4. [§5.4] The sentence 'We note there are over 300 permitted and forbidden [Fevii] lines...' appears to refer to [FeII] lines, not [FeVII], given the context of testing [FeII]19F. Please clarify.
  5. [Figure 2 caption] Caption contains a grammatical glitch: 'highlights the and respective multicomponent fits' should be 'highlights the respective multicomponent fits'.

Circularity Check

0 steps flagged

No significant circularity: the central AGN claim rests on independently measured emission lines and external model comparisons; self-citations are not load-bearing.

full rationale

The paper's derivation chain is data-driven rather than circular. The central claims—broad Balmer emission/absorption, extreme [OIII]4364/Hγ ratios, and the possible [FeVII]5160 detection—are extracted from JWST/NIRSpec spectra using an external fitting code (BADASS) and compared against external shock and photoionization models. There is no fitted parameter that is renamed as a prediction: the emission lines are measured, and the AGN interpretation is argued from the high ionization potential of [FeVII] (99 eV), the elevated O++ temperature, and the failure of shock models to reproduce the observed ratios. The paper explicitly tests the main alternative identification of the 5160 Å feature as [FeII]19F (Section 5.4, Figure 7), and while that test is not fully symmetric (the [FeII]19F component is fixed in velocity and width while [FeVII] is free), this is a limitation of the line-identification argument rather than a circular derivation. The authors also openly label the [FeVII] detection as 'possible' and note the absence of [FeVII]6088, which is a correctness risk, not a circularity. Some earlier classifications, redshifts, and complementary spectra are taken from papers with overlapping authorship (e.g., RUBIES, CEERS, GO-4287), but these are not load-bearing for the new claim: the THRILS spectrum itself provides the redshift and the line measurements, and the AGN conclusion is not defined in terms of those prior classifications. No self-definitional, fitted-input-as-prediction, or imported-uniqueness pattern is present.

Axiom & Free-Parameter Ledger

1 free parameters · 5 axioms · 0 invented entities

The paper's central claims rest on standard astrophysical modeling assumptions rather than on free parameters fitted to force a result. The most important are the line identification at 5160 Å, the Case B prior for narrow Balmer components, the broad assumed electron-density range, and the adoption of Lyα trapping and shock-model prescriptions from the literature. No invented entities.

free parameters (1)
  • narrow Balmer amplitude priors (Hα, Hβ) = not fitted; scaled from Hγ via Case B at T_e=10^4 K, n_e=10^2 cm^-3
    Methods 5.3: needed because absorption at the line centers makes narrow Hα/Hβ amplitudes degenerate.
axioms (5)
  • domain assumption The 5160 Å feature is [FeVII]λ5160, not FeII 19F or Mg I b blends
    Section 5.4, Figure 7: alternative identifications tested but not fully excluded; underpins the 'multiply ionized iron' claim.
  • domain assumption Case B recombination applies to narrow Balmer emission at T_e=10^4 K, n_e=10^2 cm^-3
    Methods 5.3: priors for Hα and Hβ narrow components derived from Hγ.
  • domain assumption Electron density of the nebular gas lies in 10^2 to 10^7 cm^-3
    Section 2.2: density diagnostics unavailable; the temperature conclusion is checked across this range.
  • domain assumption Lyα trapping in dense, Compton-thin neutral hydrogen populates n=2 (Hall 2007)
    Section 3: invoked to explain Balmer absorption without n_e above 10^9 cm^-3; external model adopted.
  • domain assumption Stellar populations and shocks cannot produce the observed [OIII]4363/Hγ ratio and temperatures
    Section 2.2: compared with Allen and Fabian shock models and stellar synthesis; underpins the AGN conclusion.

pith-pipeline@v1.3.0-alltime-deepseek · 31911 in / 15638 out tokens · 165102 ms · 2026-08-04T18:44:55.321516+00:00 · methodology

0 comments
read the original abstract

Some of the most puzzling discoveries of NASA's JWST in the early Universe surround the surprising abundance of compact red sources, which show peculiar continuum shapes and broad hydrogen spectral lines. These sources, dubbed ``Little Red Dots'' or LRDs, have been the subject of intense inquiry in the literature. Any of the proposed explanations, from accreting super-massive black holes ensconced in ultra-dense gas to extremely compact star-systems, has significant implications for the earliest phases of galaxy evolution. Part of the difficulty in concretely identifying the physical mechanisms that drive their rest ultra-violet/optical spectral properties is the lack of bona fide signatures -- either star-formation or accreting super-massive black hole, that uniquely discriminate between competing interpretations. In this work, we report the discovery of several spectral features that strongly favor the existence of an accreting super-massive black hole in an LRD witnessed in the first 800 Myr of cosmic time, including several rare iron transitions and a possible [FeVII]. Additionally, we report on the properties of significant Balmer absorption and find that the small widths and relative depths of the absorption feature suggest the source of the absorber is at or beyond the outer edge of the broad-line region and does it fully cover the accreting SMBH in the center of the system. The detection of these iron features, coupled with the properties of the Balmer absorption, unveils an alternative scenario for LRDs -- one where there are direct sight-lines from the accretion disk to gas on scales at (or beyond) the broad-line gas region.

discussion (0)

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

Forward citations

Cited by 15 Pith papers

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

  1. The GlimmIr: Spectroscopic Variability in a z~7 LRD Indicates Rapid Changes in Both the Narrow and Broad Line Regions

    astro-ph.GA 2026-04 unverdicted novelty 8.0

    First spectroscopic variability in a z~7 LRD shows rapid changes in both narrow and broad line regions, implying direct ionization from the central source to surrounding nebular gas.

  2. Misaligned or chaotic? A strong break of axial symmetry in the local LRD J1025 revealed with VLT/FORS2 spectropolarimetry

    astro-ph.GA 2026-07 accept novelty 7.0

    The local Little Red Dot J1025 shows a 48° polarisation-angle offset between continuum and broad H-alpha, requiring broken axial symmetry.

  3. 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.

  4. 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...

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

    astro-ph.GA 2026-05 unverdicted novelty 7.0

    High-resolution spectra show Balmer absorption in 4/10 LRDs with blue-shifted velocities and exponential wings, supporting a model of co-located partial-covering gas with inflow/outflow gradients.

  6. Probing Higgs and Top Interactions through the Muon Lens at multi-TeV Muon Colliders

    hep-ph 2026-04 conditional novelty 7.0

    A z=6.64 Little Red Dot host shows an AGN-driven ionised outflow reaching ~5500 km/s FWHM, with low mass-loading and clear LRD spectral signatures in the compact nucleus.

  7. GLIMPSED: Direct evidence for a fast AGN-driven outflow from a z=6.64 Little Red Dot host galaxy

    astro-ph.GA 2026-04 unverdicted novelty 7.0

    A z=6.64 LRD host galaxy exhibits a fast AGN-driven outflow with 5500 km/s velocities, dusty gas, and low metallicity, confirming AGN presence in these systems.

  8. ATLAS. II. Extremely High Incidence of Balmer Line Absorption with Predominant Blueshifts in LRDs: Statistical Insights through Comparison with Type 1 AGNs

    astro-ph.GA 2026-07 conditional novelty 6.0

    Balmer-line absorption occurs in ~35% (14/40) of JWST little-red-dot AGNs, roughly 850x the rate in SDSS type-1 AGNs, with mostly slow blueshifted absorber velocities.

  9. Probing Higgs and Top Interactions through the Muon Lens at multi-TeV Muon Colliders

    hep-ph 2026-04 unverdicted novelty 6.0

    A 10 TeV muon collider could improve existing bounds on muon-Higgs-gauge and muon-top interactions by up to an order of magnitude over current limits and FCC-ee projections.

  10. Connecting the Dots: UV-Bright Companions of Little Red Dots as Lyman-Werner Sources Enabling Direct Collapse Black Hole Formation

    astro-ph.GA 2026-02 unverdicted novelty 6.0

    UV-bright companions to Little Red Dots provide Lyman-Werner fluxes of J21 ~ 10^2.5-10^5 that can suppress H2 cooling and enable direct collapse to massive black holes.

  11. VENUS: When Red meets Blue -- A multiply imaged Little Red Dot with an apparent blue companion behind the galaxy cluster Abell 383

    astro-ph.GA 2025-12 conditional novelty 6.0

    JWST resolves A383-LRD1 into a compact red Little Red Dot candidate and a blue companion at z≈6, magnified ~9–16× by cluster lensing.

  12. Little Red Dots at z~2 in EIGER reveal a gentle decline with respect to their peak number density at z~5

    astro-ph.GA 2026-06 unverdicted novelty 5.0

    Five LRDs at z≈2 yield number density ≈7×10^{-6} cMpc^{-3}, confirming a decline from the z≈5 peak but gentler than prior photometric estimates.

  13. X-rays Mark the Spot: The Effects of Reduced Metallicity on X-ray AGN Obscuration at High Redshift

    astro-ph.HE 2026-06 unverdicted novelty 4.0

    Lower metallicity in high-redshift tori raises the X-ray escape fraction from Compton-thick obscurers, improving prospects for detecting z~10 AGNs.

  14. The X-ray-to-UV relation does not evolve in homogeneous quasar samples

    astro-ph.HE 2026-06 unverdicted novelty 4.0

    A bias-controlled quasar sample of ~2000 objects demonstrates that the X-ray-to-UV luminosity relation remains constant from redshift 0.7 to 5.

  15. Non-LTE atmosphere models of very luminous sources and their applicability to Little Red Dots, quasi-stars, and similar objects

    astro-ph.GA 2026-05 unverdicted novelty 4.0

    Non-LTE wind atmosphere models computed with CMFGEN reproduce the SED and Balmer decrement of most Little Red Dots when dust-attenuated with Av ~2, while predicting Fe II, O I, and Ca lines, but struggle to produce bo...

Reference graph

Works this paper leans on

90 extracted references · 1 canonical work pages · cited by 14 Pith papers · 1 internal anchor

  1. [1]

    ApJ978(1), 92 (2025) https://doi.org/10.3847/ 1538-4357/ad3551 arXiv:2306.07320 [astro-ph.GA]

    Labbe, I., Greene, J.E., Bezanson, R., Fujimoto, S., Furtak, L.J., Goulding, A.D., Matthee, J., Naidu, R.P., Oesch, P.A., Atek, H., Brammer, G., Chemerynska, I., Coe, D., Cutler, S.E., Dayal, P., Feldmann, R., Franx, M., Glazebrook, K., Leja, J., Maseda, M., Marchesini, D., Nanayakkara, T., Nelson, E.J., Pan, R., Papovich, C., Price, S.H., Suess, K.A., Wa...

    Pith/arXiv arXiv 2025

  2. [2]

    arXiv e-prints, 2306–05448 (2023) https://doi.org/10.48550/arXiv.2306.05448 arXiv:2306.05448 [astro-ph.GA]

    Matthee, J., Naidu, R.P., Brammer, G., Chisholm, J., Eilers, A.-C., Goulding, A., Greene, J., Kashino, D., Labbe, I., Lilly, S.J., Mackenzie, R., Oesch, P.A., Weibel, A., Wuyts, S., Xiao, M., Bordoloi, R., Bouwens, R., van Dokkum, P., Illingworth, G., Kramarenko, I., Maseda, M.V., Mason, C., Meyer, R.A., Nelson, E.J., Reddy, N.A., Shivaei, I., Simcoe, R.A...

    Pith/arXiv arXiv doi:10.48550/arxiv.2306.05448 2023

  3. [3]

    ApJ959(1), 39 (2023) https://doi.org/10.3847/1538-4357/ ad029e arXiv:2303.11946 [astro-ph.GA]

    Harikane, Y., Zhang, Y., Nakajima, K., Ouchi, M., Isobe, Y., Ono, Y., Hatano, S., Xu, Y., Umeda, H.: A JWST/NIRSpec First Census of Broad-line AGNs at z = 4-7: Detection of 10 Faint AGNs with M BH 106-108 M ⊙ and Their Host Galaxy Properties. ApJ959(1), 39 (2023) https://doi.org/10.3847/1538-4357/ ad029e arXiv:2303.11946 [astro-ph.GA]

    Pith/arXiv arXiv 2023

  4. [4]

    arXiv e-prints, 2303–08918 (2023) https://doi.org/10.48550/arXiv

    Larson, R.L., Finkelstein, S.L., Kocevski, D.D., Hutchison, T.A., Trump, J.R., Arrabal Haro, P., Bromm, V., Cleri, N.J., Dickinson, M., Fujimoto, S., Kartal- tepe, J.S., Koekemoer, A.M., Papovich, C., Pirzkal, N., Tacchella, S., Zavala, J.A., Bagley, M., Behroozi, P., Champagne, J.B., Cole, J.W., Jung, I., Morales, A.M., Yang, G., Zhang, H., Zitrin, A., A...

    Pith/arXiv arXiv doi:10.48550/arxiv 2023

  5. [5]

    arXiv e-prints, 2308–05735 (2023) https://doi.org/10.48550/arXiv

    Furtak, L.J., Labb´ e, I., Zitrin, A., Greene, J.E., Dayal, P., Chemerynska, I., Kokorev, V., Miller, T.B., Goulding, A.D., Bezanson, R., Brammer, G.B., Cut- ler, S.E., Leja, J., Pan, R., Price, S.H., Wang, B., Weaver, J.R., Whitaker, K.E., Atek, H., Bogd´ an,´A., Charlot, S., Curtis-Lake, E., van Dokkum, P., Endsley, R., Fudamoto, Y., Fujimoto, S., de Gr...

    Pith/arXiv arXiv doi:10.48550/arxiv.2308.05735 2023

  6. [6]

    Greene, J.E., Labbe, I., Goulding, A.D., Furtak, L.J., Chemerynska, I., Kokorev, V., Dayal, P., Williams, C.C., Wang, B., Setton, D.J., Burgasser, A.J., Bezanson, R., Atek, H., Brammer, G., Cutler, S.E., Feldmann, R., Fujimoto, S., Glazebrook, K., de Graaff, A., Leja, J., Marchesini, D., Maseda, M.V., Matthee, J., Miller, T.B., Naidu, R.P., Nanayakkara, T...

  7. [7]

    arXiv e-prints, 2309–05714 (2023) https://doi.org/10.48550/arXiv.2309.05714 arXiv:2309.05714 [astro-ph.GA]

    Pith/arXiv arXiv doi:10.48550/arxiv.2309.05714 2023

  8. [8]

    arXiv e-prints, 2308–11610 (2023) https://doi.org/10.48550/arXiv.2308.11610 arXiv:2308.11610 [astro-ph.GA]

    Kokorev, V., Fujimoto, S., Labbe, I., Greene, J.E., Bezanson, R., Dayal, P., Nelson, E.J., Atek, H., Brammer, G., Caputi, K.I., Chemerynska, I., Cutler, S.E., Feldmann, R., Fudamoto, Y., Furtak, L.J., Goulding, A.D., de Graaff, A., Leja, J., Marchesini, D., Miller, T.B., Nanayakkara, T., Oesch, P., Pan, R., Price, S.H., Setton, D.J., Smit, R., Stefanon, M...

    Pith/arXiv arXiv doi:10.48550/arxiv.2308.11610 2023

  9. [9]

    arXiv e-prints, 2302–00012 (2023) https://doi.org/10.48550/arXiv.2302.00012 arXiv:2302.00012 [astro-ph.GA]

    Kocevski, D.D., Onoue, M., Inayoshi, K., Trump, J.R., Arrabal Haro, P., Grazian, A., Dickinson, M., Finkelstein, S.L., Kartaltepe, J.S., Hirschmann, M., Fujimoto, S., Juneau, S., Amorin, R.O., Bagley, M.B., Barro, G., Bell, E.F., Bisigello, L., Calabro, A., Cleri, N.J., Cooper, M.C., Ding, X., Grogin, N.A., Ho, L.C., Inoue, A.K., Jiang, L., Jones, B., Koe...

    Pith/arXiv arXiv doi:10.48550/arxiv.2302.00012 2023

  10. [10]

    ApJ986(2), 126 (2025) https://doi.org/10.3847/1538-4357/adbc7d arXiv:2404.03576 [astro-ph.GA]

    Kocevski, D.D., Finkelstein, S.L., Barro, G., Taylor, A.J., Calabr` o, A., Laloux, B., Buchner, J., Trump, J.R., Leung, G.C.K., Yang, G., Dickinson, M., P´ erez- Gonz´ alez, P.G., Pacucci, F., Inayoshi, K., Somerville, R.S., McGrath, E.J., Akins, H.B., Bagley, M.B., Bowler, R.A.A., Bisigello, L., Carnall, A., Casey, C.M., 21 Cheng, Y., Cleri, N.J., Costan...

    Pith/arXiv arXiv 2025

  11. [11]

    ApJ968(1), 38 (2024) https://doi.org/10.3847/1538-4357/ad4265 arXiv:2401.09981 [astro-ph.GA]

    Kokorev, V., Caputi, K.I., Greene, J.E., Dayal, P., Trebitsch, M., Cutler, S.E., Fujimoto, S., Labb´ e, I., Miller, T.B., Iani, E., Navarro-Carrera, R., Rinaldi, P.: A Census of Photometrically Selected Little Red Dots at 4 ¡ z ¡ 9 in JWST Blank Fields. ApJ968(1), 38 (2024) https://doi.org/10.3847/1538-4357/ad4265 arXiv:2401.09981 [astro-ph.GA]

    Pith/arXiv arXiv 2024

  12. [12]

    AAP691, 52 (2024) https://doi

    Killi, M., Watson, D., Brammer, G., McPartland, C., Antwi-Danso, J., Newshore, R., Coe, D., Allen, N., Fynbo, J.P.U., Gould, K., Heintz, K.E., Rusakov, V., Vejlgaard, S.: Deciphering the JWST spectrum of a ’little red dot’ at z∼4.53: An obscured AGN and its star-forming host. AAP691, 52 (2024) https://doi. org/10.1051/0004-6361/202348857 arXiv:2312.03065 ...

    arXiv 2024

  13. [13]

    lit- tle red dots

    Akins, H.B., Casey, C.M., Lambrides, E., Allen, N., Andika, I.T., Brinch, M., Champagne, J.B., Cooper, O., Ding, X., Drakos, N.E., Faisst, A., Finkelstein, S.L., Franco, M., Fujimoto, S., Gentile, F., Gillman, S., Gozaliasl, G., Harish, S., Hayward, C.C., Hirschmann, M., Ilbert, O., Kartaltepe, J.S., Kocevski, D.D., Koekemoer, A.M., Kokorev, V., Liu, D., ...

    Pith/arXiv arXiv doi:10.48550/arxiv.2406.10341 2024

  14. [14]

    ApJ986(2), 165 (2025) https: //doi.org/10.3847/1538-4357/add15b arXiv:2409.06772 [astro-ph.GA] 22

    Taylor, A.J., Finkelstein, S.L., Kocevski, D.D., Jeon, J., Bromm, V., Amor ´ ın, R.O., Arrabal Haro, P., Backhaus, B.E., Bagley, M.B., Banados, E., Bhatawdekar, R., Brooks, M., Calabr` o, A., Ch´ avez Ortiz,´O.A., Cheng, Y., Cleri, N.J., Cole, J.W., Davis, K., Dickinson, M., Donnan, C., Dunlop, J.S., Ellis, R.S., Fern´ andez, V., Fontana, A., Fujimoto, S....

    Pith/arXiv arXiv 2025

  15. [15]

    Barro, G., P´ erez-Gonz´ alez, P.G., Kocevski, D.D., McGrath, E.J., Trump, J.R., Simons, R.C., Somerville, R.S., Yung, L.Y.A., Arrabal Haro, P., Akins, H.B., Bagley, M.B., Cleri, N.J., Costantin, L., Davis, K., Dickinson, M., Finkelstein, S.L., Giavalisco, M., G´ omez-Guijarro, C., Hathi, N.P., Hirschmann, M., Holwerda, B.W., Huertas-Company, M., Kartalte...

    Pith/arXiv arXiv 2024

  16. [16]

    arXiv e-prints, 2506–05459 (2025) https://doi.org/10.48550/arXiv.2506.05459 arXiv:2506.05459 [astro-ph.GA]

    Hviding, R.E., de Graaff, A., Miller, T.B., Setton, D.J., Greene, J.E., Labb´ e, I., Brammer, G., Bezanson, R., Boogaard, L.A., Cleri, N.J., Leja, J., Maseda, M.V., McConachie, I., Matthee, J., Naidu, R.P., Oesch, P.A., Wang, B., Whitaker, K.E., Williams, C.: RUBIES: A Spectroscopic Census of Little Red Dots; All V-Shaped Point Sources Have Broad Lines. a...

    doi:10.48550/arxiv.2506.05459 2025

  17. [17]

    Ananna, T.T., Bogd´ an, ´A., Kov´ acs, O.E., Natarajan, P., Hickox, R.C.: X-Ray View of Little Red Dots: Do They Host Supermassive Black Holes? ApJL 969(1), 18 (2024) https://doi.org/10.3847/2041-8213/ad5669 arXiv:2404.19010 [astro-ph.GA]

    Pith/arXiv arXiv 2024

  18. [18]

    Little Red Dots

    Yue, M., Eilers, A.-C., Ananna, T.T., Panagiotou, C., Kara, E., Miyaji, T.: Stacking X-ray Observations of “Little Red Dots”: Implications for their AGN Properties. arXiv e-prints, 2404–13290 (2024) https://doi.org/10.48550/arXiv. 2404.13290 arXiv:2404.13290 [astro-ph.GA]

    Pith/arXiv arXiv doi:10.48550/arxiv.2404.13290 2024

  19. [19]

    17847 arXiv:2406.17847 [astro-ph.HE]

    Lupi, A., Trinca, A., Volonteri, M., Dotti, M., Mazzucchelli, C.: Size matters: are we witnessing super-Eddington accretion in high-redshift black holes from JWST? arXiv e-prints, 2406–17847 (2024) https://doi.org/10.48550/arXiv.2406. 17847 arXiv:2406.17847 [astro-ph.HE]

    Pith/arXiv arXiv doi:10.48550/arxiv.2406 2024

  20. [20]

    arXiv e-prints, 2409–13047 (2024) https://doi.org/10.48550/arXiv.2409.13047 arXiv:2409.13047 [astro-ph.HE]

    Lambrides, E., Garofali, K., Larson, R., Ptak, A., Chiaberge, M., Long, A.S., Hutchison, T.A., Norman, C., McKinney, J., Akins, H.B., Berg, D.A., Chisholm, J., Civano, F., Cloonan, A.P., Endsley, R., Faisst, A.L., Gilli, R., Gillman, S., Hirschmann, M., Kartaltepe, J.S., Kocevski, D.D., Kokorev, V., Pacucci, F., Richardson, C.T., Stiavelli, M., Whalen, K....

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

  21. [21]

    ApJ968(1), 34 (2024) https://doi.org/10.3847/1538-4357/ad3f17 arXiv:2311.07483 [astro-ph.GA]

    Williams, C.C., Alberts, S., Ji, Z., Hainline, K.N., Lyu, J., Rieke, G., Endsley, R., Suess, K.A., Sun, F., Johnson, B.D., Florian, M., Shivaei, I., Rujopakarn, W., Baker, W.M., Bhatawdekar, R., Boyett, K., Bunker, A.J., Cameron, A.J., Carniani, S., Charlot, S., Curtis-Lake, E., DeCoursey, C., de Graaff, A., Egami, 23 E., Eisenstein, D.J., Gibson, J.L., H...

    Pith/arXiv arXiv 2024

  22. [22]

    arXiv e-prints, 2403–02304 (2024) https://doi.org/10.48550/arXiv.2403.02304 arXiv:2403.02304 [astro-ph.GA]

    Wang, B., de Graaff, A., Davies, R.L., Greene, J.E., Leja, J., Goulding, A.D., Williams, C.C., Brammer, G.B., Suess, K.A., Weibel, A., Bezanson, R., Boogaard, L.A., Cleri, N.J., Hirschmann, M., Katz, H., Labbe, I., Maseda, M.V., Matthee, J., McConachie, I., Naidu, R.P., Oesch, P.A., Rix, H.-W., Setton, D.J., Whitaker, K.E.: RUBIES: JWST/NIRSpec Confirmati...

    Pith/arXiv arXiv doi:10.48550/arxiv.2403.02304 2024

  23. [23]

    arXiv e-prints, 2508–20177 (2025) https://doi.org/10.48550/arXiv.2508.20177 arXiv:2508.20177 [astro-ph.GA]

    Ronayne, K., Papovich, C., Kirkpatrick, A., Backhaus, B.E., Cullen, F., Shen, L., Bagley, M.B., Barro, G., Finkelstein, S.L., Hamblin, K., Kartaltepe, J.S., Kocevski, D.D., Koekemoer, A.M., Lambrides, E., Pacucci, F., Yang, G.: MEGA: Spectrophotometric SED Fitting of Little Red Dots Detected in JWST MIRI. arXiv e-prints, 2508–20177 (2025) https://doi.org/...

    Pith/arXiv arXiv doi:10.48550/arxiv.2508.20177 2025

  24. [24]

    arXiv e-prints, 2508–18358 (2025) https://doi.org/10.48550/arXiv.2508.18358 arXiv:2508.18358 [astro-ph.GA]

    Wang, B., Leja, J., Katz, H., Inayoshi, K., Cleri, N.J., de Graaff, A., Hviding, R.E., van Dokkum, P., Greene, J.E., Labb´ e, I., Matthee, J., McConachie, I., Naidu, R.P., Nelson, E.J.: The Missing Hard Photons of Little Red Dots: Their Inci- dent Ionizing Spectra Resemble Massive Stars. arXiv e-prints, 2508–18358 (2025) https://doi.org/10.48550/arXiv.250...

    Pith/arXiv arXiv doi:10.48550/arxiv.2508.18358 2025

  25. [25]

    arXiv e-prints, 2407–05094 (2024) https://doi.org/10.48550/arXiv.2407.05094 arXiv:2407.05094 [astro-ph.GA]

    Casey, C.M., Akins, H.B., Kokorev, V., McKinney, J., Cooper, O.R., Long, A.S., Franco, M., Manning, S.M.: Dust in Little Red Dots. arXiv e-prints, 2407–05094 (2024) https://doi.org/10.48550/arXiv.2407.05094 arXiv:2407.05094 [astro-ph.GA]

    Pith/arXiv arXiv doi:10.48550/arxiv.2407.05094 2024

  26. [26]

    arXiv e-prints, 2405–00504 (2024) https: //doi.org/10.48550/arXiv.2405.00504 arXiv:2405.00504 [astro-ph.GA]

    Maiolino, R., Risaliti, G., Signorini, M., Trefoloni, B., Juodzbalis, I., Scholtz, J., Uebler, H., D’Eugenio, F., Carniani, S., Fabian, A., Ji, X., Mazzolari, G., Bertola, E., Brusa, M., Bunker, A.J., Charlot, S., Comastri, A., Cresci, G., DeCoursey, C.N., Egami, E., Fiore, F., Gilli, R., Perna, M., Tacchella, S., Venturi, G.: JWST meets Chandra: a large ...

    Pith/arXiv arXiv doi:10.48550/arxiv.2405.00504 2024

  27. [27]

    MNRAS531(1), 550–553 (2024) https://doi.org/10.1093/mnras/stae1171 arXiv:2404.16832 [astro-ph.GA]

    King, A.: The black hole masses of high-redshift QSOs. MNRAS531(1), 550–553 (2024) https://doi.org/10.1093/mnras/stae1171 arXiv:2404.16832 [astro-ph.GA]

    Pith/arXiv arXiv 2024

  28. [28]

    arXiv e-prints, 2407–15915 (2024) https://doi.org/10.48550/arXiv.2407.15915 24 arXiv:2407.15915 [astro-ph.HE]

    Pacucci, F., Narayan, R.: Mildly Super-Eddington Accretion Onto Slowly- Spinning Black Holes Explains the X-Ray Weakness of the Little Red Dots. arXiv e-prints, 2407–15915 (2024) https://doi.org/10.48550/arXiv.2407.15915 24 arXiv:2407.15915 [astro-ph.HE]

    Pith/arXiv arXiv doi:10.48550/arxiv.2407.15915 2024

  29. [29]

    arXiv e-prints, 2411–12005 (2024) https://doi.org/10.48550/arXiv.2411.12005 arXiv:2411.12005 [astro-ph.GA]

    Leung, G.C.K., Finkelstein, S.L., P´ erez-Gonz´ alez, P.G., Morales, A.M., Taylor, A.J., Barro, G., Kocevski, D.D., Akins, H.B., Carnall, A.C., Ch´ avez Ortiz,´O.A., Cleri, N.J., Cullen, F., Donnan, C.T., Dunlop, J.S., Ellis, R.S., Grogin, N.A., Hirschmann, M., Koekemoer, A.M., Kokorev, V., Lucas, R.A., McLeod, D.J., Papovich, C., Yung, L.Y.A.: Exploring ...

    Pith/arXiv arXiv doi:10.48550/arxiv.2411.12005 2024

  30. [30]

    arXiv e-prints, 2408–07745 (2024) https://doi.org/10.48550/arXiv.2408.07745 arXiv:2408.07745 [astro-ph.GA]

    Baggen, J.F.W., van Dokkum, P., Brammer, G., de Graaff, A., Franx, M., Greene, J., Labb´ e, I., Leja, J., Maseda, M.V., Nelson, E.J., Rix, H.-W., Wang, B., Weibel, A.: The Small Sizes and High Implied Densities of ‘Little Red Dots’ with Balmer Breaks Could Explain Their Broad Emission Lines Without an AGN. arXiv e-prints, 2408–07745 (2024) https://doi.org...

    Pith/arXiv arXiv doi:10.48550/arxiv.2408.07745 2024

  31. [31]

    arXiv e-prints, 2412–04557 (2024) https://doi.org/10.48550/arXiv.2412.04557 arXiv:2412.04557 [astro-ph.GA]

    Labbe, I., Greene, J.E., Matthee, J., Treiber, H., Kokorev, V., Miller, T.B., Kra- marenko, I., Setton, D.J., Ma, Y., Goulding, A.D., Bezanson, R., Naidu, R.P., Williams, C.C., Atek, H., Brammer, G., Cutler, S.E., Chemerynska, I., Cloo- nan, A.P., Dayal, P., de Graaff, A., Fudamoto, Y., Fujimoto, S., Furtak, L.J., Glazebrook, K., Heintz, K.E., Leja, J., M...

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

  32. [32]

    ApJ974(1), 147 (2024) https://doi.org/10.3847/1538-4357/ad6565 arXiv:2407.17570 [astro-ph.GA]

    Lin, X., Wang, F., Fan, X., Cai, Z., Champagne, J.B., Sun, F., Volonteri, M., Yang, J., Hennawi, J.F., Ba˜ nados, E., Barth, A., Eilers, A.-C., Farina, E.P., Liu, W., Jin, X., Jun, H.D., Lupi, A., Kakiichi, K., Mazzucchelli, C., Onoue, M., Pan, Z., Pizzati, E., Rojas-Ruiz, S., Schindler, J.-T., Trakhtenbrot, B., Shen, Y., Trebitsch, M., Zhuang, M.-Y., End...

    Pith/arXiv arXiv 2024

  33. [33]

    arXiv e-prints, 2503–16600 (2025) https: //doi.org/10.48550/arXiv.2503.16600 arXiv:2503.16600 [astro-ph.GA]

    de Graaff, A., Rix, H.-W., Naidu, R.P., Labbe, I., Wang, B., Leja, J., Matthee, J., Katz, H., Greene, J.E., Hviding, R.E., Baggen, J., Bezanson, R., Boogaard, L.A., Brammer, G., Dayal, P., van Dokkum, P., Goulding, A.D., Hirschmann, M., Maseda, M.V., McConachie, I., Miller, T.B., Nelson, E., Oesch, P.A., Setton, D.J., Shivaei, I., Weibel, A., Whitaker, K....

    Pith/arXiv arXiv doi:10.48550/arxiv.2503.16600 2025

  34. [35]

    Black Hole Star

    Naidu, R.P., Matthee, J., Katz, H., de Graaff, A., Oesch, P., Smith, A., Greene, J.E., Brammer, G., Weibel, A., Hviding, R., Chisholm, J., Labb\’e, I., Simcoe, R.A., Witten, C., Atek, H., Baggen, J.F.W., Belli, S., Bezanson, R., Boogaard, L.A., Bose, S., Covelo-Paz, A., Dayal, P., Fudamoto, Y., Furtak, L.J., Giovinazzo, E., Goulding, A., Gronke, M., Heint...

    Pith/arXiv arXiv doi:10.48550/arxiv.2503.16596 2025

  35. [36]

    arXiv e-prints, 2501–13082 (2025) https://doi.org/10.48550/ arXiv.2501.13082 arXiv:2501.13082 [astro-ph.GA]

    Ji, X., Maiolino, R., ¨Ubler, H., Scholtz, J., D’Eugenio, F., Sun, F., Perna, M., Turner, H., Arribas, S., Bennett, J.S., Bunker, A., Carniani, S., Charlot, S., Cresci, G., Curti, M., Egami, E., Fabian, A., Inayoshi, K., Isobe, Y., Jones, G., Juodˇ zbalis, I., Kumari, N., Lyu, J., Mazzolari, G., Parlanti, E., Robertson, B., Rodr ´ ıguez Del Pino, B., Schn...

    doi:10.48550/arxiv.2501.13082 2025

  36. [37]

    ApJL989(1), 7 (2025) https://doi.org/10.3847/2041-8213/ade789 arXiv:2505.04609 [astro-ph.GA] 26

    Taylor, A.J., Kokorev, V., Kocevski, D.D., Akins, H.B., Cullen, F., Dickinson, M., Finkelstein, S.L., Arrabal Haro, P., Bromm, V., Giavalisco, M., Inayoshi, K., Juneau, S., Leung, G.C.K., P´ erez-Gonz´ alez, P.G., Somerville, R.S., Trump, J.R., Amor ´ ın, R.O., Barro, G., Burgarella, D., Brooks, M., Carnall, A.C., Casey, C.M., Cheng, Y., Chisholm, J., Chw...

    Pith/arXiv arXiv 2025

  37. [38]

    ApJS141(2), 267–309 (2002) https://doi.org/10.1086/340546 arXiv:astro-ph/0203252 [astro-ph]

    Hall, P.B., Anderson, S.F., Strauss, M.A., York, D.G., Richards, G.T., Fan, X., Knapp, G.R., Schneider, D.P., Vanden Berk, D.E., Geballe, T.R., Bauer, A.E., Becker, R.H., Davis, M., Rix, H.-W., Nichol, R.C., Bahcall, N.A., Brinkmann, J., Brunner, R., Connolly, A.J., Csabai, I., Doi, M., Fukugita, M., Gunn, J.E., Haiman, Z., Harvanek, M., Heckman, T.M., He...

    Pith/arXiv arXiv 2002

  38. [39]

    AJ133(4), 1271–1274 (2007) https://doi.org/10.1086/511272 arXiv:astro-ph/0611922 [astro- ph]

    Hall, P.B.: A Quasar with Broad Absorption in the Balmer Lines. AJ133(4), 1271–1274 (2007) https://doi.org/10.1086/511272 arXiv:astro-ph/0611922 [astro- ph]

    Pith/arXiv arXiv 2007

  39. [40]

    ApJ373, 23 (1991) https://doi.org/10.1086/170020

    Weymann, R.J., Morris, S.L., Foltz, C.B., Hewett, P.C.: Comparisons of the Emission-Line and Continuum Properties of Broad Absorption Line and Normal Quasi-stellar Objects. ApJ373, 23 (1991) https://doi.org/10.1086/170020

    doi:10.1086/170020 1991

  40. [41]

    ApJ853(2), 167 (2018) https://doi.org/10.3847/1538-4357/aaa7f0 arXiv:1710.08563 [astro-ph.GA]

    Schulze, A., Misawa, T., Zuo, W., Wu, X.-B.: Discovery of Strong Balmer Line Absorption in Two Luminous LoBAL Quasars at z∼1.5. ApJ853(2), 167 (2018) https://doi.org/10.3847/1538-4357/aaa7f0 arXiv:1710.08563 [astro-ph.GA]

    Pith/arXiv arXiv 2018

  41. [42]

    arXiv e-prints, 2508–08768 (2025) https://doi.org/10.48550/arXiv.2508.08768 arXiv:2508.08768 [astro-ph.GA]

    Chang, S.-J., Gronke, M., Matthee, J., Mason, C.: Impact of Resonance, Raman, and Thomson Scattering on Hydrogen Line Formation in Little Red Dots. arXiv e-prints, 2508–08768 (2025) https://doi.org/10.48550/arXiv.2508.08768 arXiv:2508.08768 [astro-ph.GA]

    doi:10.48550/arxiv.2508.08768 2025

  42. [43]

    ApJ815(2), 113 (2015) https://doi.org/10.1088/ 0004-637X/815/2/113 arXiv:1511.03422 [astro-ph.GA]

    Zhang, S., Zhou, H., Shi, X., Shu, X., Liu, W., Ji, T., Jiang, P., Sun, L., Zhou, J., Pan, X.: Discovery of Extremely Broad Balmer Absorption Lines in SDSS J152350.42+391405.2. ApJ815(2), 113 (2015) https://doi.org/10.1088/ 0004-637X/815/2/113 arXiv:1511.03422 [astro-ph.GA]

    Pith/arXiv arXiv 2015

  43. [44]

    ApJL980(2), 27 (2025) https://doi.org/10.3847/ 2041-8213/adaebd arXiv:2409.07805 [astro-ph.GA]

    Inayoshi, K., Maiolino, R.: Extremely Dense Gas around Little Red Dots and High-redshift Active Galactic Nuclei: A Nonstellar Origin of the Balmer Break and Absorption Features. ApJL980(2), 27 (2025) https://doi.org/10.3847/ 2041-8213/adaebd arXiv:2409.07805 [astro-ph.GA]

    Pith/arXiv arXiv 2025

  44. [45]

    MNRAS535(1), 853–873 (2024) https://doi.org/10.1093/mnras/stae2367 arXiv:2407.08643 [astro-ph.GA] 27

    Juodˇ zbalis, I., Ji, X., Maiolino, R., D’Eugenio, F., Scholtz, J., Risaliti, G., Fabian, A.C., Mazzolari, G., Gilli, R., Prandoni, I., Arribas, S., Bunker, A.J., Carniani, S., Charlot, S., Curtis-Lake, E., de Graaff, A., Hainline, K., Parlanti, E., Perna, M., P´ erez-Gonz´ alez, P.G., Robertson, B., Tacchella, S.,¨Ubler, H., Williams, C.C., Willott, C., ...

    Pith/arXiv arXiv 2024

  45. [46]

    arXiv e-prints, 2503–11752 (2025) https://doi.org/10.48550/arXiv.2503.11752 arXiv:2503.11752 [astro-ph.GA]

    D’Eugenio, F., Maiolino, R., Perna, M., Uebler, H., Ji, X., McClymont, W., Koudmani, S., Sijacki, D., Juodˇ zbalis, I., Scholtz, J., Bennett, J., Bunker, A.J., Carniani, S., Charlot, S., Cresci, G., Curtis-Lake, E., Dalla Bont` a, E., Jones, G.C., Lyu, J., Marconi, A., Mazzolari, G., Nelson, E.J., Parlanti, E., Robertson, B.E., Schneider, R., Simmonds, C....

    Pith/arXiv arXiv doi:10.48550/arxiv.2503.11752 2025

  46. [47]

    AAP697, 189 (2025) https://doi.org/10.1051/0004-6361/ 202452186 arXiv:2409.05948 [astro-ph.GA]

    de Graaff, A., Brammer, G., Weibel, A., Lewis, Z., Maseda, M.V., Oesch, P.A., Bezanson, R., Boogaard, L.A., Cleri, N.J., Cooper, O.R., Gottumukkala, R., Greene, J.E., Hirschmann, M., Hviding, R.E., Katz, H., Labb´ e, I., Leja, J., Matthee, J., McConachie, I., Miller, T.B., Naidu, R.P., Price, S.H., Rix, H.-W., Setton, D.J., Suess, K.A., Wang, B., Whitaker...

    Pith/arXiv arXiv 2025

  47. [48]

    MNRAS467(1), 540–572 (2017) https://doi.org/10

    Lamperti, I., Koss, M., Trakhtenbrot, B., Schawinski, K., Ricci, C., Oh, K., Landt, H., Riffel, R., Rodr ´ ıguez-Ardila, A., Gehrels, N., Harrison, F., Masetti, N., Mushotzky, R., Treister, E., Ueda, Y., Veilleux, S.: BAT AGN Spectroscopic Survey - IV: Near-Infrared Coronal Lines, Hidden Broad Lines, and Correlation with Hard X-ray Emission. MNRAS467(1), ...

    Pith/arXiv arXiv 2017

  48. [49]

    ApJ936(2), 140 (2022) https://doi.org/10.3847/1538-4357/ac8981 arXiv:2208.10532 [astro-ph.GA]

    Reefe, M., Satyapal, S., Sexton, R.O., Doan, S.M., Secrest, N.J., Cann, J.M.: CLASS: Coronal Line Activity Spectroscopic Survey. ApJ936(2), 140 (2022) https://doi.org/10.3847/1538-4357/ac8981 arXiv:2208.10532 [astro-ph.GA]

    Pith/arXiv arXiv 2022

  49. [50]

    ApJ 948(2), 112 (2023) https://doi.org/10.3847/1538-4357/acc1e6 arXiv:2209.06247 [astro-ph.GA]

    Cleri, N.J., Yang, G., Papovich, C., Trump, J.R., Backhaus, B.E., Estrada- Carpenter, V., Finkelstein, S.L., Giavalisco, M., Hutchison, T.A., Ji, Z., Jung, I., Matharu, J., Momcheva, I., Olivier, G.M., Simons, R., Weiner, B.: CLEAR: High-ionization [Ne V]λ3426 Emission-line Galaxies at 1.4 ¡ z ¡ 2.3. ApJ 948(2), 112 (2023) https://doi.org/10.3847/1538-435...

    Pith/arXiv arXiv 2023

  50. [51]

    ApJ953(1), 10 (2023) https://doi.org/10.3847/1538-4357/ acde55 arXiv:2301.07745 [astro-ph.GA]

    Cleri, N.J., Olivier, G.M., Hutchison, T.A., Papovich, C., Trump, J.R., Amor ´ ın, R.O., Backhaus, B.E., Berg, D.A., Fern´ andez, V., Finkelstein, S.L., Fujimoto, S., Hirschmann, M., Kartaltepe, J.S., Kocevski, D.D., Simons, R.C., Wilkins, S.M., Yung, L.Y.A.: Using [Ne V]/[Ne III] to Understand the Nature of Extreme- ionization Galaxies. ApJ953(1), 10 (20...

    Pith/arXiv arXiv 2023

  51. [52]

    Cleri, N.J., Olivier, G.M., Backhaus, B.E., Leja, J., Papovich, C., Trump, J.R., Arrabal Haro, P., Buat, V., Burgarella, D., Burnham, E., Calabro, A., Cohn, 28 J.H., Cole, J.W., Davis, K., Dickinson, M., Finkelstein, S.L., Garner, R. III, Hirschmann, M., Hu, W., Hutchison, T.A., Kocevski, D.D., Koekemoer, A.M., Larson, R.L., Lewis, Z.J., Maseda, M.V., Sei...

    Pith/arXiv arXiv doi:10.48550/arxiv.2506.21660 2025

  52. [53]

    ApJL983(1), 4 (2025) https://doi.org/10.3847/2041-8213/adbbd3 arXiv:2501.04085 [astro-ph.GA]

    Finkelstein, S.L., Bagley, M.B., Arrabal Haro, P., Dickinson, M., Ferguson, H.C., Kartaltepe, J.S., Kocevski, D.D., Koekemoer, A.M., Lotz, J.M., Papovich, C., P´ erez-Gonz´ alez, P.G., Pirzkal, N., Somerville, R.S., Trump, J.R., Yang, G., Yung, L.Y.A., Fontana, A., Grazian, A., Grogin, N.A., Kewley, L.J., Kirkpatrick, A., Larson, R.L., Pentericci, L., Rav...

    Pith/arXiv arXiv 2025

  53. [54]

    ApJL969(1), 13 (2024) https://doi.org/10.3847/ 2041-8213/ad55f7 arXiv:2405.01473 [astro-ph.GA]

    Wang, B., Leja, J., de Graaff, A., Brammer, G.B., Weibel, A., van Dokkum, P., Baggen, J.F.W., Suess, K.A., Greene, J.E., Bezanson, R., Cleri, N.J., Hirschmann, M., Labb´ e, I., Matthee, J., McConachie, I., Naidu, R.P., Nelson, E., Oesch, P.A., Setton, D.J., Williams, C.C.: RUBIES: Evolved Stellar Populations with Extended Formation Histories at z∼7–8 in C...

    Pith/arXiv arXiv 2024

  54. [55]

    arXiv e-prints, 2505–06359 (2025) https://doi.org/10.48550/arXiv.2505.06359 arXiv:2505.06359 [astro-ph.GA]

    Tang, M., Stark, D.P., Plat, A., Feltre, A., Katz, H., Senchyna, P., Mason, C.A., Whitler, L., Chen, Z., Topping, M.W.: JWST/NIRSpec Observations of High Ionization Emission Lines in Galaxies at High Redshift. arXiv e-prints, 2505–06359 (2025) https://doi.org/10.48550/arXiv.2505.06359 arXiv:2505.06359 [astro-ph.GA]

    Pith/arXiv arXiv doi:10.48550/arxiv.2505.06359 2025

  55. [56]

    ApJL946(1), 12 (2023) https://doi.org/10.3847/2041-8213/acbb08 arXiv:2211.02495 [astro-ph.IM]

    Bagley, M.B., Finkelstein, S.L., Koekemoer, A.M., Ferguson, H.C., Arrabal Haro, P., Dickinson, M., Kartaltepe, J.S., Papovich, C., P´ erez-Gonz´ alez, P.G., 29 Pirzkal, N., Somerville, R.S., Willmer, C.N.A., Yang, G., Yung, L.Y.A., Fontana, A., Grazian, A., Grogin, N.A., Hirschmann, M., Kewley, L.J., Kirkpatrick, A., Kocevski, D.D., Lotz, J.M., Medrano, A...

    Pith/arXiv arXiv 2023

  56. [57]

    AAP691, 345 (2024) https: //doi.org/10.1051/0004-6361/202450407 arXiv:2404.10811 [astro-ph.GA]

    Mazzolari, G., ¨Ubler, H., Maiolino, R., Ji, X., Nakajima, K., Feltre, A., Scholtz, J., D’Eugenio, F., Curti, M., Mignoli, M., Marconi, A.: New AGN diagnostic diagrams based on the [OIII]λ4363 auroral line. AAP691, 345 (2024) https: //doi.org/10.1051/0004-6361/202450407 arXiv:2404.10811 [astro-ph.GA]

    Pith/arXiv arXiv 2024

  57. [58]

    arXiv e-prints, 2502–03519 (2025) https: //doi.org/10.48550/arXiv.2502.03519 arXiv:2502.03519 [astro-ph.GA]

    Backhaus, B.E., Cleri, N.J., Trump, J.R., Kirkpatrick, A., Simons, R.C., Arra- bal Haro, P., Bagley, M.B., Brooks, M., Calabr` o, A., Davis, K., Dickinson, M., Finkelstein, S.L., Hirschmann, M., Kartaltepe, J.S., Koekemoer, A.M., Llerena, M., Pacucci, F., Pirzkal, N., Papovich, C., Wilkins, S.M.: Emission-Line Diag- nostics at z¿4: [OIII]4363/H-gamma. arX...

    Pith/arXiv arXiv doi:10.48550/arxiv.2502.03519 2025

  58. [59]

    MNRAS286(3), 583–603 (1997) https: //doi.org/10.1093/mnras/286.3.583 arXiv:astro-ph/9612032 [astro-ph]

    Allen, S.W., Fabian, A.C.: The spatial distributions of cooling gas and intrinsic X-ray-absorbing material in cooling flows. MNRAS286(3), 583–603 (1997) https: //doi.org/10.1093/mnras/286.3.583 arXiv:astro-ph/9612032 [astro-ph]

    Pith/arXiv arXiv 1997

  59. [60]

    MNRAS462(2), 1757–1774 (2016) https: //doi.org/10.1093/mnras/stw1716 arXiv:1607.06086 [astro-ph.GA]

    Gutkin, J., Charlot, S., Bruzual, G.: Modelling the nebular emission from primeval to present-day star-forming galaxies. MNRAS462(2), 1757–1774 (2016) https: //doi.org/10.1093/mnras/stw1716 arXiv:1607.06086 [astro-ph.GA]

    Pith/arXiv arXiv 2016

  60. [61]

    RMxAA 51, 103–120 (2015) https://doi.org/10.48550/arXiv.1412.5349 arXiv:1412.5349 [astro-ph.GA]

    Morisset, C., Delgado-Inglada, G., Flores-Fajardo, N.: A virtual observatory for photoionized nebulae: the Mexican Million Models database (3MdB). RMxAA 51, 103–120 (2015) https://doi.org/10.48550/arXiv.1412.5349 arXiv:1412.5349 [astro-ph.GA]

    Pith/arXiv arXiv doi:10.48550/arxiv.1412.5349 2015

  61. [62]

    AJ122(2), 549–564 (2001) https://doi.org/10.1086/321167 arXiv:astro- ph/0105231 [astro-ph]

    Vanden Berk, D.E., Richards, G.T., Bauer, A., Strauss, M.A., Schneider, D.P., Heckman, T.M., York, D.G., Hall, P.B., Fan, X., Knapp, G.R., Anderson, S.F., Annis, J., Bahcall, N.A., Bernardi, M., Briggs, J.W., Brinkmann, J., Brunner, R., Burles, S., Carey, L., Castander, F.J., Connolly, A.J., Crocker, J.H., Csabai, I., Doi, M., Finkbeiner, D., Friedman, S....

    arXiv 2001

  62. [63]

    ApJS189(1), 15–36 (2010) https://doi.org/10.1088/0067-0049/189/1/15 arXiv:1004.2212 [astro-ph.CO]

    Kovaˇ cevi´ c, J., Popovi´ c, L.ˇC., Dimitrijevi´ c, M.S.: Analysis of Optical Fe II Emis- sion in a Sample of Active Galactic Nucleus Spectra. ApJS189(1), 15–36 (2010) https://doi.org/10.1088/0067-0049/189/1/15 arXiv:1004.2212 [astro-ph.CO]

    Pith/arXiv arXiv 2010

  63. [64]

    RMXAA53, 385–438 (2017) https://doi.org/10

    Ferland, G.J., Chatzikos, M., Guzm´ an, F., Lykins, M.L., van Hoof, P.A.M., Williams, R.J.R., Abel, N.P., Badnell, N.R., Keenan, F.P., Porter, R.L., Stancil, P.C.: The 2017 Release Cloudy. RMXAA53, 385–438 (2017) https://doi.org/10. 48550/arXiv.1705.10877 arXiv:1705.10877 [astro-ph.GA]

    Pith/arXiv arXiv doi:10.48550/arxiv.1705.10877 2017

  64. [65]

    AAP 694, 289 (2025) https://doi.org/10.1051/0004-6361/202450516 arXiv:2501.17611 [astro-ph.GA]

    Kovaˇ cevi´ c-Dojˇ cinovi´ c, J., Dojˇ cinovi´ c, I., Laki´ cevi´ c, M., Popovi´ c, L.ˇC.: Searching for signatures of Fe II atomic processes in spectra of active galactic nuclei. AAP 694, 289 (2025) https://doi.org/10.1051/0004-6361/202450516 arXiv:2501.17611 [astro-ph.GA]

    Pith/arXiv arXiv 2025

  65. [66]

    MNRAS372(1), 5–8 (2006) https://doi.org/10.1111/j.1745-3933

    Zhang, X.-G., Dultzin-Hacyan, D., Wang, T.-G.: SDSS J2125-0813: the evidence for the origination of optical FeII emission lines from an accretion disc near a cen- tral black hole. MNRAS372(1), 5–8 (2006) https://doi.org/10.1111/j.1745-3933. 2006.00214.x

    Pith/arXiv arXiv 2006

  66. [68]

    NGC 5548: The AGN Energy Budget Problem and the Geometry of the Broad-Line Region and Torus

    Gaskell, C.M., Klimek, E.S., Nazarova, L.S.: NGC 5548: The AGN Energy Budget Problem and the Geometry of the Broad-Line Region and Torus. arXiv e-prints, 0711–1025 (2007) https://doi.org/10.48550/arXiv.0711.1025 arXiv:0711.1025 [astro-ph]

    work page internal anchor Pith review Pith/arXiv arXiv doi:10.48550/arxiv.0711.1025 2007

  67. [69]

    NAR53(7-10), 140–148 (2009) https://doi.org/10.1016/j.newar.2009.09

    Gaskell, C.M.: What broad emission lines tell us about how active galactic nuclei work. NAR53(7-10), 140–148 (2009) https://doi.org/10.1016/j.newar.2009.09. 006 arXiv:0908.0386 [astro-ph.CO]

    Pith/arXiv arXiv 2009

  68. [70]

    ApJ820(2), 116 (2016) https://doi.org/ 10.3847/0004-637X/820/2/116

    Marinello, M., Rodr ´ ıguez-Ardila, A., Garcia-Rissmann, A., Sigut, T.A.A., Prad- han, A.K.: The Fe II Emission in Active Galactic Nuclei: Excitation Mechanisms and Location of the Emitting Region. ApJ820(2), 116 (2016) https://doi.org/ 10.3847/0004-637X/820/2/116

    doi:10.3847/0004-637x/820/2/116 2016

  69. [71]

    ApJS120(1), 101–112 (1999) https://doi.org/10.1086/313171

    Verner, E.M., Verner, D.A., Korista, K.T., Ferguson, J.W., Hamann, F., Ferland, G.J.: Numerical Simulations of Fe II Emission Spectra. ApJS120(1), 101–112 (1999) https://doi.org/10.1086/313171

    doi:10.1086/313171 1999

  70. [72]

    ApJ675(1), 83–95 (2008) https://doi.org/10.1086/525557 31

    Bruhweiler, F., Verner, E.: Modeling Fe II Emission and Revised Fe II (UV) Empirical Templates for the Seyfert 1 Galaxy I Zw 1. ApJ675(1), 83–95 (2008) https://doi.org/10.1086/525557 31

    doi:10.1086/525557 2008

  71. [73]

    Zhang, X.: Are There Higher Electron Densities in Narrow Emission Line Regions of Type-1 AGNs than in Type-2 AGNs? ApJ960(2), 108 (2024) https://doi.org/ 10.3847/1538-4357/ad029a arXiv:2309.00852 [astro-ph.GA]

    Pith/arXiv arXiv 2024

  72. [74]

    ApJS277(2), 36 (2025) https://doi.org/10.3847/1538-4365/adb427 arXiv:2401.18052 [astro-ph.GA]

    Pandey, A., Mart ´ ınez-Aldama, M.L., Czerny, B., Panda, S., Zajaˇ cek, M., Wang, J.-M., Li, Y.-R., Du, P.: New Theoretical Fe II Templates for Bright Quasars. ApJS277(2), 36 (2025) https://doi.org/10.3847/1538-4365/adb427 arXiv:2401.18052 [astro-ph.GA]

    Pith/arXiv arXiv 2025

  73. [75]

    AAP417, 515–525 (2004) https://doi.org/10.1051/0004-6361:20035714 arXiv:astro-ph/0312654 [astro-ph]

    V´ eron-Cetty, M.-P., Joly, M., V´ eron, P.: The unusual emission line spectrum of I Zw 1. AAP417, 515–525 (2004) https://doi.org/10.1051/0004-6361:20035714 arXiv:astro-ph/0312654 [astro-ph]

    Pith/arXiv arXiv 2004

  74. [76]

    ApJ927(2), 165 (2022) https://doi.org/10.3847/1538-4357/ac510c arXiv:2202.01330 [astro- ph.GA]

    Richardson, C.T., Simpson, C., Polimera, M.S., Kannappan, S.J., Bellovary, J.M., Greene, C., Jenkins, S.: Optical and JWST Mid-IR Emission Line Diagnostics for Simultaneous IMBH and Stellar Excitation in z 0 Dwarf Galaxies. ApJ927(2), 165 (2022) https://doi.org/10.3847/1538-4357/ac510c arXiv:2202.01330 [astro- ph.GA]

    Pith/arXiv arXiv 2022

  75. [77]

    McKaig, J.D., Satyapal, S., Laor, A., Abel, N.P., Doan, S.M., Ricci, C., Cann, J.M.: Why Are Optical Coronal Lines Faint in Active Galactic Nuclei? ApJ 976(1), 130 (2024) https://doi.org/10.3847/1538-4357/ad7a79 arXiv:2408.15229 [astro-ph.GA]

    Pith/arXiv arXiv 2024

  76. [78]

    ApJS 265(1), 21 (2023) https://doi.org/10.3847/1538-4365/acb0d2 arXiv:2211.11882 [astro-ph.GA]

    Reefe, M., Sexton, R.O., Doan, S.M., Satyapal, S., Secrest, N.J., Cann, J.M.: CLASS Survey Description: Coronal-line Needles in the SDSS Haystack. ApJS 265(1), 21 (2023) https://doi.org/10.3847/1538-4365/acb0d2 arXiv:2211.11882 [astro-ph.GA]

    Pith/arXiv arXiv 2023

  77. [79]

    Frontiers in Astronomy and Space Sciences4, 12 (2017) https://doi.org/10.3389/fspas.2017.00012 arXiv:1803.10860 [astro-ph.GA]

    Ili´ c, D., Shapovalova, A.I., Popovi´ c, L.ˇC., Chavushyan, V., Burenkov, A.N., Kollatschny, W., Kovaˇ cevi´ c, A., Marˇ ceta-Mandi´ c, S., Raki´ c, N., La Mura, G., Rafanelli, P.: Long-Term Monitoring of the Broad-Line Region Properties in a Selected Sample of AGN. Frontiers in Astronomy and Space Sciences4, 12 (2017) https://doi.org/10.3389/fspas.2017....

    arXiv 2017

  78. [80]

    ApJ230, 360–372 (1979) https://doi.org/10.1086/ 157092

    Oke, J.B., Lauer, T.R.: An analysis of the spectra of the Seyfert galaxies Markarian 79 and I Zw 1. ApJ230, 360–372 (1979) https://doi.org/10.1086/ 157092

    1979

  79. [81]

    ApJS80, 109 (1992) https://doi.org/10.1086/191661

    Boroson, T.A., Green, R.F.: The Emission-Line Properties of Low-Redshift Quasi- stellar Objects. ApJS80, 109 (1992) https://doi.org/10.1086/191661

    doi:10.1086/191661 1992

  80. [82]

    MNRAS449(4), 3795–3805 (2015) https: //doi.org/10.1093/mnras/stv062 arXiv:1501.02928 [astro-ph.GA]

    Landt, H., Ward, M.J., Steenbrugge, K.C., Ferland, G.J.: Variability of the coronal line region in NGC 4151. MNRAS449(4), 3795–3805 (2015) https: //doi.org/10.1093/mnras/stv062 arXiv:1501.02928 [astro-ph.GA]

    Pith/arXiv arXiv 2015

Showing first 80 references.