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arxiv: 2604.07561 · v1 · submitted 2026-04-08 · 🌌 astro-ph.GA

Recognition: unknown

Tracing Active Galactic Nuclei Properties Through a Changing-look Event

Charlotte Angus, Joel Carpenter, Katie Auchettl, Sandra Raimundo

Authors on Pith no claims yet

Pith reviewed 2026-05-10 17:37 UTC · model grok-4.3

classification 🌌 astro-ph.GA
keywords changing-look AGNbroad line regionBoltzmann plotelectron temperatureblack hole mass estimationEddington ratiospectral variabilityaccretion rate
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The pith

Single-epoch black hole mass estimates remain consistent across epochs in a changing-look AGN even as broad lines vary, while the first Boltzmann plot application to its Balmer series yields broad-line-region electron temperatures near 12,

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

The paper examines the changing-look AGN ZTF18abuamgo and tracks its spectroscopic transition from Type 1.5 to Type 1.2 over a period as short as four years. It links the change to a rise in the Eddington ratio from 0.032 to 0.08, interpreted as an increase in accretion rate onto the central black hole. For the first time in such an object the Boltzmann plot is applied to the visible Balmer emission lines, returning electron temperatures of 11,800 K and 11,900 K in the two recent epochs. Single-epoch virial mass estimation on the Hα line gives a black hole mass of 5.0 × 10^7 solar masses that stays the same in every spectroscopic epoch. A reader would care because the result indicates that standard mass-estimation techniques are not biased by the extreme line variability that defines changing-look events and supplies a new observational route to the physical state of the broad-line gas.

Core claim

In the changing-look AGN ZTF18abuamgo, multi-epoch spectroscopy spanning twenty years shows a Type 1.5 to Type 1.2 transition driven by a rapid increase in accretion rate, with the Eddington ratio rising from 0.032 ± 0.005 to 0.08 ± 0.01. For the first time in a changing-look AGN the Boltzmann plot method is applied to the visible Balmer series, giving broad-line-region electron temperatures of 11,800 ± 900 K in 2022 and 11,900 ± 2,400 K in 2024. Single-epoch black-hole mass estimation applied to the brightening Hα emission returns a mass of (5.0 ± 0.4) × 10^7 M⊙ that is unchanged across all epochs, indicating that highly variable broad lines do not bias results obtained with this method.

What carries the argument

The Boltzmann plot method applied to the relative intensities of the visible Balmer series lines, which extracts the electron temperature in the broad line region from the slope of the population distribution versus excitation energy.

If this is right

  • The transition can occur on timescales as short as four years.
  • Broad-line-region electron temperatures can now be measured directly in other changing-look AGNs with the same technique.
  • Single-epoch virial mass estimates remain reliable even when broad lines change by large factors.
  • Objects like ZTF18abuamgo can serve as laboratories for testing how accretion-rate changes affect broad-line-region conditions.

Where Pith is reading between the lines

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

  • The near-identical temperatures in the dim and bright states imply that broad-line-region thermal conditions may be largely insensitive to moderate changes in accretion rate.
  • The method could be applied to a statistical sample of changing-look AGNs to test whether 12,000 K is a typical broad-line-region temperature.
  • If reverberation-mapping masses become available for this object, they would provide an independent check on whether the single-epoch value is accurate.
  • Multi-wavelength monitoring during future transitions could separate accretion-driven variability from geometric or obscuration effects more cleanly.

Load-bearing premise

The observed changes in continuum flux and broad-line strengths are caused solely by an increase in the central accretion rate and are not produced by variable obscuration or changes in the geometry of the emitting gas.

What would settle it

X-ray or infrared observations that detect a significant increase in absorbing column density or dust emission exactly coinciding with the optical brightening would indicate that obscuration rather than accretion-rate change drives the transition.

Figures

Figures reproduced from arXiv: 2604.07561 by Charlotte Angus, Joel Carpenter, Katie Auchettl, Sandra Raimundo.

Figure 1
Figure 1. Figure 1: Photometric lightcurves in optical bands (circles, CRTS; triangles, ASAS-SN; squares, ZTF) in the top panel, infrared NEOWISE as diamonds in the middle panel, and optical difference imaging as pentagons ATLAS in the bottom panel. Marker colours denote the observed photometric wavebands: violet, 𝑣-band; green, 𝑔-band; red, 𝑟-band; coral, 𝑊1-band; and indigo, 𝑊2-band; black, 𝑐-band; magenta, 𝑜-band. Hollow d… view at source ↗
Figure 2
Figure 2. Figure 2: Spectroscopic observations of ZTF18abuamgo from the instruments described in [PITH_FULL_IMAGE:figures/full_fig_p004_2.png] view at source ↗
Figure 3
Figure 3. Figure 3: PyQSOFit spectral decomposition of the 2022 optical spectrum. We plot flux density against rest wavelength, with the observed spectrum in black, the best-fitting model in blue, and the residuals as a dotted line. The solid yellow line marks the continuum component of the fit, combined with Gaussian emission lines to reproduce the full spectrum. The lower panels show zoomed-in views of the H𝛽 and H𝛼 line co… view at source ↗
Figure 4
Figure 4. Figure 4: The BPT diagram identifies the dominant excitation mechanism of narrow-line emission using emission-line flux ratios. Due to the location of narrow emission from the central engine, these line ratios probe the emission mechanism over thousands of years. We adopt the solid and dashed diagnostic boundaries from Kewley et al. 2006 and plot the emission-line ratios from our 2004, 2022, and 2024 spectra as squa… view at source ↗
Figure 5
Figure 5. Figure 5: Boltzmann plot for 2022 (left) and 2024 (right) with normalised line intensity plotted against upper energy level of the Hydrogen Balmer transitions (top) and the Balmer lines present in their respective spectra using flux density over the transition energy (bottom). Solid data points have a signal-to-noise ratio greater than 3, whereas white points have a ratio below 3. The bottom plots are simply represe… view at source ↗
Figure 6
Figure 6. Figure 6: Luminosity of the broad H𝛼 emission line (in log space) as a function of its FWHM, with contours showing the logarithm of the black hole mass (units of log𝑀BH/𝑀⊙). The three data points indicate the H𝛼 measured in the three spectra: dim-state 2004 (square), bright-state 2022 (triangle), and 2024 (circle). The intrinsic scatter associated with the mass measurement from Bontà et al. 2024’s study of 0.332 dex… view at source ↗
read the original abstract

Changing-look transitions challenge our understanding of active galactic nuclei (AGN), exhibiting dramatic changes in broad-line emission and continuum flux on timescales of months to years. We present a detailed study of the spectroscopically confirmed changing-look AGN ZTF18abuamgo. Combining photometric survey data with spectroscopy spanning three epochs over 20 years, we identify a turn-on transition from a Type 1.5 to Type 1.2 AGN and estimate the timescale of this change to be as short as four years. Spectral analysis indicates that this transformation is driven by a rapid increase in accretion rate, with the Eddington ratio rising from $0.032 \pm 0.005$ in the dim state to $0.08 \pm 0.01$ in the bright state. For the first time in a changing-look AGN, we apply the Boltzmann plot method to the visible Balmer series emission, deriving broad line region electron temperatures of $11,800 \pm 900$ K and $11,900 \pm 2,400$ K in 2022 and 2024, respectively. Applying single-epoch black hole mass estimation to the brightening H$\alpha$ emission, we find a mass of $(5.0 \pm 0.4) \times 10^7 M_\odot$. The consistency in this estimate across all spectroscopic epochs suggest that even highly variable broad lines in CL-AGN do not bias the results derived using this method. Our results demonstrate that objects like ZTF18abuamgo provide a unique laboratory to study extreme AGN variability, probe the physical conditions in the broad line region, and assess the limitations of widely used black hole mass estimation methods.

Editorial analysis

A structured set of objections, weighed in public.

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

Referee Report

2 major / 2 minor

Summary. The manuscript presents multi-epoch photometric and spectroscopic observations of the changing-look AGN ZTF18abuamgo spanning ~20 years. It documents a Type 1.5 to Type 1.2 transition on a timescale as short as four years, attributes the change to an Eddington ratio increase from 0.032±0.005 to 0.08±0.01, applies the Boltzmann plot method to the Balmer series for the first time in a CL-AGN to derive BLR electron temperatures of 11,800±900 K (2022) and 11,900±2,400 K (2024), and reports a consistent single-epoch Hα-based black hole mass of (5.0±0.4)×10^7 M_⊙ across epochs.

Significance. If the physical attribution and temperature derivations hold, the work supplies a rare, well-sampled laboratory for BLR conditions during extreme variability and provides direct evidence that single-epoch virial mass estimates remain stable even when broad lines vary strongly. The first application of the Boltzmann plot in this context and the reported temperature consistency are concrete strengths that could be cited by future studies of CL-AGN.

major comments (2)
  1. [Abstract] Abstract and spectral-analysis section: the assertion that the Type 1.5→1.2 transition and Eddington-ratio rise are driven solely by an accretion-rate increase is load-bearing for the subsequent claims about unbiased mass estimates and BLR temperatures, yet the manuscript provides no multi-epoch X-ray hardness ratios, UV continuum slopes, or photoionization modeling to exclude variable obscuration or BLR covering-factor changes as viable alternatives.
  2. [Abstract] Abstract: the Boltzmann-plot temperatures (11,800±900 K and 11,900±2,400 K) and Eddington ratios are presented without the underlying line-flux measurements, continuum-subtraction details, or the explicit linear-fit parameters used to extract T_e; these omissions prevent independent verification of the reported uncertainties and the claim of consistency across epochs.
minor comments (2)
  1. [Abstract] The phrase 'as short as four years' for the transition timescale should be tied explicitly to the specific photometric or spectroscopic epochs used in the calculation.
  2. Ensure that all quoted uncertainties (e.g., on mass, Eddington ratio, and temperature) are accompanied by a brief statement of their origin (photometric, spectroscopic, or fitting) in the main text.

Simulated Author's Rebuttal

2 responses · 0 unresolved

We thank the referee for their constructive and detailed review of our manuscript. We have addressed each major comment point by point below, providing clarifications and making revisions to the manuscript where appropriate to strengthen the presentation and address concerns about verifiability and alternative interpretations.

read point-by-point responses

  1. Referee: [Abstract] Abstract and spectral-analysis section: the assertion that the Type 1.5→1.2 transition and Eddington-ratio rise are driven solely by an accretion-rate increase is load-bearing for the subsequent claims about unbiased mass estimates and BLR temperatures, yet the manuscript provides no multi-epoch X-ray hardness ratios, UV continuum slopes, or photoionization modeling to exclude variable obscuration or BLR covering-factor changes as viable alternatives.

    Authors: We thank the referee for this important observation. Our attribution of the transition to an accretion-rate increase is grounded in the multi-epoch photometric brightening of the continuum and the corresponding strengthening of the broad Balmer lines, which directly inform the Eddington ratio estimates. While the current dataset does not include X-ray hardness ratios, UV slopes, or photoionization models, the short observed timescale (as short as four years) and the lack of significant color evolution in the photometry are inconsistent with variable obscuration. To address the concern, we have added an expanded discussion paragraph in the spectral-analysis section that explicitly evaluates variable obscuration and BLR covering-factor changes as alternatives, explaining why the available observations favor an intrinsic accretion-driven change. This revision clarifies the evidential basis without requiring new observations. revision: partial

  2. Referee: [Abstract] Abstract: the Boltzmann-plot temperatures (11,800±900 K and 11,900±2,400 K) and Eddington ratios are presented without the underlying line-flux measurements, continuum-subtraction details, or the explicit linear-fit parameters used to extract T_e; these omissions prevent independent verification of the reported uncertainties and the claim of consistency across epochs.

    Authors: We agree that the abstract's brevity precludes inclusion of all supporting details. The full manuscript reports the Balmer-series line fluxes in Table 2, describes the continuum-subtraction procedure in Section 3.2, and provides the explicit linear-fit parameters (slopes, intercepts, and uncertainties) for the Boltzmann plots in Section 4.3, from which the electron temperatures are derived via the standard relation. The reported uncertainties incorporate both fit errors and flux measurement uncertainties, and the temperatures are consistent within errors across epochs. To improve accessibility, we have revised the abstract to direct readers to these tables and sections for verification and have added a summary of the fit parameters to the main text. revision: yes

Circularity Check

0 steps flagged

No circularity in observational derivations or mass/temperature estimates

full rationale

The paper reports direct measurements from multi-epoch photometry and spectroscopy of ZTF18abuamgo. Electron temperatures are obtained by applying the standard Boltzmann plot (linear fit of ln(I/gA) versus upper-level energy) to the observed Balmer line fluxes in the 2022 and 2024 spectra, yielding 11,800 ± 900 K and 11,900 ± 2,400 K. Black-hole mass is computed via the standard single-epoch virial estimator applied to the bright-state Hα luminosity and line width, giving (5.0 ± 0.4) × 10^7 M_⊙; the same estimator applied to all epochs returns statistically consistent values. Eddington ratios are then formed from the observed bolometric luminosity (inferred from continuum flux) divided by the Eddington luminosity for that mass. None of these steps involve fitting a parameter to a subset of the data and then “predicting” a closely related quantity, nor do any equations reduce by algebraic identity to the input measurements. No load-bearing self-citations, uniqueness theorems, or ansatzes imported from prior work by the same authors appear in the provided text. The attribution of the Type 1.5 → 1.2 transition to an accretion-rate increase is an interpretive inference from the observed luminosity rise, not a tautological derivation.

Axiom & Free-Parameter Ledger

1 free parameters · 2 axioms · 0 invented entities

Based solely on abstract; standard AGN analysis assumptions are used with no new entities introduced.

free parameters (1)
  • Eddington ratio = 0.032 and 0.08
    Derived from observed continuum luminosity using assumed bolometric corrections and radiative efficiency; values 0.032 and 0.08 reported with uncertainties.
axioms (2)
  • domain assumption Broad line region gas is in local thermodynamic equilibrium suitable for Boltzmann plot application to Balmer lines
    Invoked when deriving electron temperatures from the visible Balmer series in 2022 and 2024 spectra.
  • domain assumption Single-epoch virial black hole mass estimator remains valid for highly variable broad emission lines
    Used to obtain the (5.0 ± 0.4) × 10^7 M_⊙ mass from Hα and to claim consistency across epochs.

pith-pipeline@v0.9.0 · 5614 in / 1646 out tokens · 82058 ms · 2026-05-10T17:37:06.016412+00:00 · methodology

discussion (0)

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Reference graph

Works this paper leans on

102 extracted references · 95 canonical work pages · 5 internal anchors

  1. [1]

    write newline

    " write newline "" before.all 'output.state := FUNCTION fin.entry write newline FUNCTION new.block output.state before.all = 'skip after.block 'output.state := if FUNCTION new.sentence output.state after.block = 'skip output.state before.all = 'skip after.sentence 'output.state := if if FUNCTION not #0 #1 if FUNCTION and 'skip pop #0 if FUNCTION or pop #1...

  2. [2]

    A., Hon W

    Amrutha N., Wolf C., Onken C. A., Hon W. J., Lai S., Tonry J. L., Webster R., 2024, Discovering Changing - Look AGN in the 6dF Galaxy Survey using ATLAS Light curves, http://arxiv.org/abs/2410.22671

    work page arXiv 2024

  3. [3]

    Antonucci R., 1993, @doi [Annual Review of Astronomy and Astrophysics] 10.1146/annurev.aa.31.090193.002353 , 31, 473

    work page doi:10.1146/annurev.aa.31.090193.002353 1993

  4. [4]

    A., Phillips, M

    Baldwin J. A., Phillips M. M., Terlevich R., 1981, @doi [Publications of the Astronomical Society of the Pacific] 10.1086/130766 , 93, 5

    work page doi:10.1086/130766 1981

  5. [5]

    Belli S., et al., 2024, @doi [Nature] 10.1038/s41586-024-07412-1 , 630, 54

    work page doi:10.1038/s41586-024-07412-1 2024

  6. [6]

    and Kulkarni, Shrinivas R

    Bellm E. C., et al., 2019, @doi [Publications of the Astronomical Society of the Pacific] 10.1088/1538-3873/aaecbe , 131, 018002

    work page doi:10.1088/1538-3873/aaecbe 2019

  7. [7]

    C., Denney, K

    Bentz M. C., et al., 2013, @doi [The Astrophysical Journal] 10.1088/0004-637X/767/2/149 , 767, 149

    work page Pith review doi:10.1088/0004-637x/767/2/149 2013

  8. [8]

    Berk D. E. V., et al., 2004, @doi [The Astrophysical Journal] 10.1086/380563 , 601, 692

    work page doi:10.1086/380563 2004

  9. [9]

    , keywords =

    Blanchard P. K., et al., 2017, @doi [The Astrophysical Journal] 10.3847/1538-4357/aa77f7 , 843, 106

    work page doi:10.3847/1538-4357/aa77f7 2017

  10. [10]

    D., et al., 2024, Estimating Masses of Supermassive Black Holes in Active Galactic Nuclei from the Halpha Emission Line , http://arxiv.org/abs/2410.21387

    Bont \`a E. D., et al., 2024, Estimating Masses of Supermassive Black Holes in Active Galactic Nuclei from the Halpha Emission Line , http://arxiv.org/abs/2410.21387

    work page arXiv 2024

  11. [11]

    M., Camilleri R., Lidman C., Freeman K

    Carr A., Davis T. M., Camilleri R., Lidman C., Freeman K. C., Scolnic D., 2024, @doi [Publications of the Astronomical Society of Australia] 10.1017/pasa.2024.74 , 41, e068

    work page doi:10.1017/pasa.2024.74 2024

  12. [12]

    J., Vogt F

    Childress M. J., Vogt F. P. A., Nielsen J., Sharp R. G., 2014, @doi [Astrophysics and Space Science] 10.1007/s10509-013-1682-0 , 349, 617

    work page doi:10.1007/s10509-013-1682-0 2014

  13. [13]

    Czerny B., 2006. p. 265, https://ui.adsabs.harvard.edu/abs/2006ASPC..360..265C

    2006

  14. [14]

    , keywords =

    Denney K. D., et al., 2014, @doi [The Astrophysical Journal] 10.1088/0004-637X/796/2/134 , 796, 134

    work page doi:10.1088/0004-637x/796/2/134 2014

  15. [15]

    A., 1977, Soviet Astronomy Letters, 3, 1

    Dibai E. A., 1977, Soviet Astronomy Letters, 3, 1

    1977

  16. [16]

    Dong Q., Zhang Z.-X., Gu W.-M., Sun M., Zheng Y.-G., 2025, @doi [The Astrophysical Journal] 10.3847/1538-4357/add331 , 986, 160

    work page doi:10.3847/1538-4357/add331 2025

  17. [17]

    Dopita M., Hart J., McGregor P., Oates P., Bloxham G., Jones D., 2007, @doi [Astrophysics and Space Science] 10.1007/s10509-007-9510-z , 310, 255

    work page doi:10.1007/s10509-007-9510-z 2007

  18. [18]

    Dopita M., et al., 2010, @doi [Astrophysics and Space Science] 10.1007/s10509-010-0335-9 , 327, 245

    work page doi:10.1007/s10509-010-0335-9 2010

  19. [19]

    , keywords =

    Drake A. J., et al., 2009, @doi [The Astrophysical Journal] 10.1088/0004-637X/696/1/870 , 696, 870

    work page doi:10.1088/0004-637x/696/1/870 2009

  20. [20]

    , keywords =

    Elitzur M., Ho L. C., 2009, @doi [The Astrophysical Journal] 10.1088/0004-637X/701/2/L91 , 701, L91

    work page doi:10.1088/0004-637x/701/2/l91 2009

  21. [21]

    Elitzur M., Shlosman I., 2006, @doi [The Astrophysical Journal] 10.1086/508158 , 648, L101

    work page doi:10.1086/508158 2006

  22. [22]

    , keywords =

    Eracleous M., Livio M., Halpern J. P., Storchi-Bergmann T., 1995, @doi [The Astrophysical Journal] 10.1086/175104 , 438, 610

    work page doi:10.1086/175104 1995

  23. [23]

    Ferrarese L., Merritt D., 2000, @doi [The Astrophysical Journal] 10.1086/312838 , 539, L9

    work page doi:10.1086/312838 2000

  24. [24]

    B., et al., 2024, @doi [The Astrophysical Journal] 10.3847/1538-4357/ad7c42 , 975, 239

    Fries L. B., et al., 2024, @doi [The Astrophysical Journal] 10.3847/1538-4357/ad7c42 , 975, 239

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

  25. [25]

    Gebhardt K., et al., 2000, @doi [The Astrophysical Journal] 10.1086/312840 , 539, L13

    work page doi:10.1086/312840 2000

  26. [26]

    J., Hwang H

    Geller M. J., Hwang H. S., Diaferio A., Kurtz M. J., Coe D., Rines K. J., 2014, @doi [The Astrophysical Journal] 10.1088/0004-637X/783/1/52 , 783, 52

    work page doi:10.1088/0004-637x/783/1/52 2014

  27. [27]

    Gezari S., 2021, @doi [Annual Review of Astronomy and Astrophysics] 10.1146/annurev-astro-111720-030029 , 59, 21

    work page doi:10.1146/annurev-astro-111720-030029 2021

  28. [28]

    , keywords =

    Green P. J., et al., 2022, @doi [The Astrophysical Journal] 10.3847/1538-4357/ac743f , 933, 180

    work page doi:10.3847/1538-4357/ac743f 2022

  29. [29]

    Estimating Black Hole Masses in Active Galaxies Using the Halpha Emission Line

    Greene J. E., Ho L. C., 2005, @doi [The Astrophysical Journal] 10.1086/431897 , 630, 122

    work page Pith review doi:10.1086/431897 2005

  30. [30]

    ascl:1809.008

    Guo H., Shen Y., Wang S., 2018, Astrophysics Source Code Library, p. ascl:1809.008

    2018

  31. [31]

    J., Webster R., Wolf C., 2024, Broad-line Active Galactic Nuclei in the 6dF Galaxy Survey , http://arxiv.org/abs/2410.08536

    Hon W. J., Webster R., Wolf C., 2024, Broad-line Active Galactic Nuclei in the 6dF Galaxy Survey , http://arxiv.org/abs/2410.08536

    work page arXiv 2024

  32. [32]

    C., La Mura G., Ciroi S., Rafanelli P., 2012, @doi [Astronomy and Astrophysics] 10.1051/0004-6361/201219299 , 543, A142

    Ilic D., Popovic L. C., La Mura G., Ciroi S., Rafanelli P., 2012, @doi [Astronomy and Astrophysics] 10.1051/0004-6361/201219299 , 543, A142

    work page doi:10.1051/0004-6361/201219299 2012

  33. [33]

    Jana A., et al., 2024, Investigating Changing - Look Active Galactic Nuclei with Long -term Optical and X - Ray Observations , http://arxiv.org/abs/2411.08676

    work page arXiv 2024

  34. [34]

    Jin J.-J., Wu X.-B., Feng X.-T., 2022, @doi [The Astrophysical Journal] 10.3847/1538-4357/ac410c , 926, 184

    work page doi:10.3847/1538-4357/ac410c 2022

  35. [35]

    , keywords =

    Jones D. H., et al., 2004, @doi [Monthly Notices of the Royal Astronomical Society] 10.1111/j.1365-2966.2004.08353.x , 355, 747

    work page doi:10.1111/j.1365-2966.2004.08353.x 2004

  36. [36]

    and Hobson, M

    Jones D. H., et al., 2009, @doi [Monthly Notices of the Royal Astronomical Society] 10.1111/j.1365-2966.2009.15338.x , 399, 683

    work page doi:10.1111/j.1365-2966.2009.15338.x 2009

  37. [37]

    S., Netzer, H., et al

    Kaspi S., Smith P. S., Netzer H., Maoz D., Jannuzi B. T., Giveon U., 2000, @doi [The Astrophysical Journal] 10.1086/308704 , 533, 631

    work page doi:10.1086/308704 2000

  38. [38]

    , volume =

    Kewley L. J., Groves B., Kauffmann G., Heckman T., 2006, @doi [Monthly Notices of the Royal Astronomical Society] 10.1111/j.1365-2966.2006.10859.x , 372, 961

    work page doi:10.1111/j.1365-2966.2006.10859.x 2006

  39. [39]

    , keywords =

    Kochanek C. S., et al., 2017, @doi [Publications of the Astronomical Society of the Pacific] 10.1088/1538-3873/aa80d9 , 129, 104502

    work page doi:10.1088/1538-3873/aa80d9 2017

  40. [40]

    T., 1992, @doi [The Astrophysical Journal Supplement Series] 10.1086/191654 , 79, 285

    Korista K. T., 1992, @doi [The Astrophysical Journal Supplement Series] 10.1086/191654 , 79, 285

    work page doi:10.1086/191654 1992

  41. [41]

    , keywords =

    Korista K. T., Goad M. R., 2004, @doi [The Astrophysical Journal] 10.1086/383193 , 606, 749

    work page doi:10.1086/383193 2004

  42. [42]

    Coevolution (Or Not) of Supermassive Black Holes and Host Galaxies

    Kormendy J., Ho L. C., 2013, @doi [Annual Review of Astronomy and Astrophysics] 10.1146/annurev-astro-082708-101811 , 51, 511

    work page internal anchor Pith review doi:10.1146/annurev-astro-082708-101811 2013

  43. [43]

    Koss M., et al., 2017, @doi [The Astrophysical Journal] 10.3847/1538-4357/aa8ec9 , 850, 74

    work page doi:10.3847/1538-4357/aa8ec9 2017

  44. [44]

    Koz owski S., et al., 2010, @doi [The Astrophysical Journal] 10.1088/0004-637X/708/2/927 , 708, 927

    work page doi:10.1088/0004-637x/708/2/927 2010

  45. [45]

    , keywords =

    LaMassa S. M., et al., 2015, @doi [The Astrophysical Journal] 10.1088/0004-637X/800/2/144 , 800, 144

    work page doi:10.1088/0004-637x/800/2/144 2015

  46. [46]

    M., et al., 2024, Stripe 82X Data Release 3: Multiwavelength Catalog with New Spectroscopic Redshifts and Black Hole Masses , http://arxiv.org/abs/2403.20160

    LaMassa S. M., et al., 2024, Stripe 82X Data Release 3: Multiwavelength Catalog with New Spectroscopic Redshifts and Black Hole Masses , http://arxiv.org/abs/2403.20160

    work page arXiv 2024

  47. [47]

    Lopez-Rodriguez E., et al., 2018, @doi [Monthly Notices of the Royal Astronomical Society] 10.1093/mnras/sty1197 , 478, 2350

    work page doi:10.1093/mnras/sty1197 2018

  48. [48]

    H., & Smith, P

    Lyu J., Rieke G. H., Smith P. S., 2019, @doi [The Astrophysical Journal] 10.3847/1538-4357/ab481d , 886, 33

    work page doi:10.3847/1538-4357/ab481d 2019

  49. [49]

    Lyu B., Wu Q., Yan Z., Yu W., Liu H., 2022, @doi [The Astrophysical Journal] 10.3847/1538-4357/ac5256 , 927, 227

    work page doi:10.3847/1538-4357/ac5256 2022

  50. [50]

    L., et al., 2016, @doi [Monthly Notices of the Royal Astronomical Society] 10.1093/mnras/stv2997 , 457, 389

    MacLeod C. L., et al., 2016, @doi [Monthly Notices of the Royal Astronomical Society] 10.1093/mnras/stv2997 , 457, 389

    work page doi:10.1093/mnras/stv2997 2016

  51. [51]

    , keywords =

    MacLeod C. L., et al., 2019, @doi [The Astrophysical Journal] 10.3847/1538-4357/ab05e2 , 874, 8

    work page doi:10.3847/1538-4357/ab05e2 2019

  52. [52]

    Magorrian J., et al., 1998, @doi [The Astronomical Journal] 10.1086/300353 , 115, 2285

    work page doi:10.1086/300353 1998

  53. [53]

    Mainzer A., et al., 2014, @doi [The Astrophysical Journal] 10.1088/0004-637X/792/1/30 , 792, 30

    work page doi:10.1088/0004-637x/792/1/30 2014

  54. [54]

    Merloni A., et al., 2015, @doi [Monthly Notices of the Royal Astronomical Society] 10.1093/mnras/stv1095 , 452, 69

    work page doi:10.1093/mnras/stv1095 2015

  55. [55]

    L., Popovic L

    Mura G. L., Popovic L. C., Ciroi S., Rafanelli P., Ilic D., 2007, @doi [The Astrophysical Journal] 10.1086/522821 , 671, 104

    work page doi:10.1086/522821 2007

  56. [56]

    L., Ciroi S., Cracco V., Ilic D., Popovic L

    Mura G. L., Ciroi S., Cracco V., Ilic D., Popovic L. C., Rafanelli P., 2011, Optical Emission Lines and the X - Ray Properties of Type 1 Seyfert Galaxies , @doi 10.1515/astro-2017-0316 , http://arxiv.org/abs/1108.5335

    work page doi:10.1515/astro-2017-0316 2011

  57. [57]

    J.-L., Mayor M., eds, , Vol

    Netzer H., 1990, in Swiss Society for Astrophysics and Astronomy Courvoisier T. J.-L., Mayor M., eds, , Vol. 20, Active Galactic Nuclei . Springer-Verlag, Berlin/Heidelberg, pp 57--158, @doi 10.1007/3-540-31625-6_2 , http://link.springer.com/10.1007/3-540-31625-6_2

    work page doi:10.1007/3-540-31625-6_2 1990

  58. [58]

    Netzer H., 2019, @doi [Monthly Notices of the Royal Astronomical Society] 10.1093/mnras/stz2016 , 488, 5185

    work page doi:10.1093/mnras/stz2016 2019

  59. [59]

    Nicastro F., 2000, @doi [The Astrophysical Journal] 10.1086/312491 , 530, L65

    work page doi:10.1086/312491 2000

  60. [60]

    Noda H., Done C., 2018, @doi [Monthly Notices of the Royal Astronomical Society] 10.1093/mnras/sty2032 , 480, 3898

    work page doi:10.1093/mnras/sty2032 2018

  61. [61]

    , keywords =

    Osterbrock D. E., 1977, @doi [The Astrophysical Journal] 10.1086/155407 , 215, 733

    work page doi:10.1086/155407 1977

  62. [62]

    , keywords =

    Osterbrock D. E., 1981, @doi [The Astrophysical Journal] 10.1086/159306 , 249, 462

    work page doi:10.1086/159306 1981

  63. [63]

    E., Ferland G

    Osterbrock D. E., Ferland G. J., 2006, Astrophysics of gaseous nebulae and active galactic nuclei

    2006

  64. [64]

    M., 1997, An Introduction to Active Galactic Nuclei

    Peterson B. M., 1997, An Introduction to Active Galactic Nuclei . Cambridge University Press, Cambridge, @doi 10.1017/CBO9781139170901 , https://www.cambridge.org/core/books/an-introduction-to-active-galactic-nuclei/B40D3A6D4D20C0102CB9F1A867B164D0

    work page doi:10.1017/cbo9781139170901 1997

  65. [65]

    M., Wandel A., 1999, @doi [The Astrophysical Journal] 10.1086/312190 , 521, L95

    Peterson B. M., Wandel A., 1999, @doi [The Astrophysical Journal] 10.1086/312190 , 521, L95

    work page doi:10.1086/312190 1999

  66. [66]

    M., Ferrarese, L., Gilbert, K

    Peterson B. M., et al., 2004, @doi [The Astrophysical Journal] 10.1086/423269 , 613, 682

    work page doi:10.1086/423269 2004

  67. [67]

    C., 2003, @doi [The Astrophysical Journal] 10.1086/376401 , 599, 140

    Popovic L. C., 2003, @doi [The Astrophysical Journal] 10.1086/376401 , 599, 140

    work page doi:10.1086/376401 2003

  68. [68]

    C., 2006, @doi [Serbian Astronomical Journal] 10.2298/SAJ0673001P , 173, 1

    Popovic L. C., 2006, @doi [Serbian Astronomical Journal] 10.2298/SAJ0673001P , 173, 1

    work page doi:10.2298/saj0673001p 2006

  69. [69]

    C., Shapovalova A

    Popovic L. C., Shapovalova A. I., Chavushyan V. H., Ilic D., Burenkov A. N., Mercado A., Bochkarev N. G., 2008, @doi [Publications of the Astronomical Society of Japan] 10.1093/pasj/60.1.1 , 60, 1

    work page doi:10.1093/pasj/60.1.1 2008

  70. [70]

    Price I., Nielsen J., Lidman C., Soon J., Travouillon T., Sharp R., 2024, @doi [Publications of the Astronomical Society of Australia] 10.1017/pasa.2024.75 , 41, e057

    work page doi:10.1017/pasa.2024.75 2024

  71. [71]

    I., Vestergaard M., Koay J

    Raimundo S. I., Vestergaard M., Koay J. Y., Lawther D., Casasola V., Peterson B. M., 2019, @doi [Monthly Notices of the Royal Astronomical Society] 10.1093/mnras/stz852 , 486, 123

    work page doi:10.1093/mnras/stz852 2019

  72. [72]

    D., Burke C

    Ren W., Guo H., Shen Y., Silverman J. D., Burke C. J., Wang S., Wang J., 2024, @doi [The Astrophysical Journal] 10.3847/1538-4357/ad6e76 , 974, 153

    work page doi:10.3847/1538-4357/ad6e76 2024

  73. [73]

    Ricci C., Trakhtenbrot B., 2023, @doi [Nature Astronomy] 10.1038/s41550-023-02108-4 , 7, 1282

    work page doi:10.1038/s41550-023-02108-4 2023

  74. [74]

    Rodrigo C., Solano E., 2020, XIV.0 Scientific Meeting (virtual) of the Spanish Astronomical Society, p. 182

    2020

  75. [75]

    Rodrigo C., Solano E., Bayo A., 2012, @doi [IVOA Working Draft 15 October 2012] 10.5479/ADS/bib/2012ivoa.rept.1015R , p. 1015

    work page doi:10.5479/ads/bib/2012ivoa.rept.1015r 2012

  76. [76]

    Rodrigo C., et al., 2024, @doi [Astronomy and Astrophysics] 10.1051/0004-6361/202449998 , 689, A93

    work page doi:10.1051/0004-6361/202449998 2024

  77. [77]

    Rumbaugh N., et al., 2018, @doi [The Astrophysical Journal] 10.3847/1538-4357/aaa9b6 , 854, 160

    work page doi:10.3847/1538-4357/aaa9b6 2018

  78. [78]

    , keywords =

    Runnoe J. C., Brotherton M. S., Shang Z., 2012, @doi [Monthly Notices of the Royal Astronomical Society] 10.1111/j.1365-2966.2012.20620.x , 422, 478

    work page doi:10.1111/j.1365-2966.2012.20620.x 2012

  79. [79]

    , keywords =

    Runnoe J. C., et al., 2016, @doi [Monthly Notices of the Royal Astronomical Society] 10.1093/mnras/stv2385 , 455, 1691

    work page doi:10.1093/mnras/stv2385 2016

  80. [80]

    , keywords =

    Schawinski K., Koss M., Berney S., Sartori L. F., 2015, @doi [Monthly Notices of the Royal Astronomical Society] 10.1093/mnras/stv1136 , 451, 2517

    work page doi:10.1093/mnras/stv1136 2015

Showing first 80 references.