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arxiv: 2606.27195 · v1 · pith:VWDYH4OEnew · submitted 2026-06-25 · 🌌 astro-ph.GA · astro-ph.CO· gr-qc· hep-ph· hep-th

HALO II: Constraining Hubble constant H₀ through continuum delay fitting of Fairall 9

Amit Kumar Mandal , Francisco Pozo Nu\~nez , Vikram Kumar Jaiswal , Mohammad Hassan Naddaf , Bo\.zena Czerny , Swayamtrupta Panda , Paulina Karczmarek , Grzegorz Pietrzy\'nski
show 23 more authors
Shivangi Pandey R. Edelson B. M. Peterson Michal Zaja\v{c}ek Alberto Floris Mary Loli Mart\'inez-Aldama Michal Dov\v{c}iak Vladimir Karas Weronika Narloch Miros{\l}aw Kicia Marek G\'orski Miko{\l}aj Ka{\l}uszy\'nski Gergely Hajdu Piotr Wielg\'orski Bart{\l}omiej Zgirski Cezary Ga{\l}an Wojciech Pych Rados{\l}aw Smolec Ricardo Salinas Henryka Netzel-I{\l}kiewicz Karolina B\k{a}kowska Wolfgang Gieren Pierre Kervella
This is my paper

Pith reviewed 2026-06-26 03:42 UTC · model grok-4.3

classification 🌌 astro-ph.GA astro-ph.COgr-qchep-phhep-th
keywords Hubble constantactive galactic nucleicontinuum time delaysaccretion diskFairall 9reverberation mappingcosmology
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The pith

Continuum time delays and SED modeling in Fairall 9 yield H0 = 72.4 km s^{-1} Mpc^{-1} independent of the cosmic distance ladder.

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

The paper presents a new method to measure the Hubble constant from time delays between different wavelengths in the continuum emission of an active galaxy's accretion disk. By monitoring Fairall 9 and fitting both the observed lag spectrum and its broadband spectral energy distribution with a radiation reprocessing model, the authors obtain a value of H0 that matches both early- and late-universe determinations within uncertainties. The approach requires no calibration against other distance indicators and achieves roughly 5 percent precision from a single source. This precision is expected to improve below 1 percent when applied to larger samples from upcoming surveys. The result demonstrates that AGN continuum reverberation can serve as a direct cosmological probe.

Core claim

Through the simultaneous modeling of the continuum lag-spectrum and the broadband SED of Fairall 9 using the H0RIZON-AGN model that incorporates radiation reprocessing in the cold accretion disk, a Hubble constant of H0=72.4_{-3.7}^{+3.4} km s^{-1} Mpc^{-1} is derived, showing that this method can deliver independent H0 measurements at approximately 5 percent precision from one object.

What carries the argument

The H0RIZON-AGN model, which predicts continuum time delays by simulating radiation reprocessing in the accretion disk and is fitted jointly to the lag spectrum and SED.

If this is right

  • The method supplies an H0 measurement entirely free from cosmic distance ladder systematics and cross-calibrations.
  • A single source already reaches 5 percent precision, indicating that samples of many AGNs can push uncertainty below 1 percent.
  • Data from the Vera Rubin Observatory are expected to enable this technique as a competitive probe of the Hubble tension.
  • The derived H0 remains consistent with both early- and late-Universe values inside current error bars.

Where Pith is reading between the lines

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

  • Repeating the analysis on a statistical sample of AGNs would test whether Fairall 9 is typical or whether source-to-source variations affect the inferred H0.
  • Incorporating additional observables such as line reverberation or X-ray lags could tighten the model constraints without changing the core distance inference.
  • If the method scales cleanly, it offers a route to map H0 across redshift using the same class of objects at different look-back times.

Load-bearing premise

The H0RIZON-AGN model correctly captures all dominant effects of radiation reprocessing in the cold accretion disk for Fairall 9 with no significant unmodeled systematics such as disk winds or non-standard temperature profiles.

What would settle it

An independent geometric distance to Fairall 9 that produces an H0 value outside the reported 72.4_{-3.7}^{+3.4} range when combined with the observed lags would falsify the central claim.

Figures

Figures reproduced from arXiv: 2606.27195 by Alberto Floris, Amit Kumar Mandal, Bart{\l}omiej Zgirski, B. M. Peterson, Bo\.zena Czerny, Cezary Ga{\l}an, Francisco Pozo Nu\~nez, Gergely Hajdu, Grzegorz Pietrzy\'nski, Henryka Netzel-I{\l}kiewicz, Karolina B\k{a}kowska, Marek G\'orski, Mary Loli Mart\'inez-Aldama, Michal Dov\v{c}iak, Michal Zaja\v{c}ek, Miko{\l}aj Ka{\l}uszy\'nski, Miros{\l}aw Kicia, Mohammad Hassan Naddaf, Paulina Karczmarek, Pierre Kervella, Piotr Wielg\'orski, Rados{\l}aw Smolec, R. Edelson, Ricardo Salinas, Shivangi Pandey, Swayamtrupta Panda, Vikram Kumar Jaiswal, Vladimir Karas, Weronika Narloch, Wojciech Pych, Wolfgang Gieren.

Figure 1
Figure 1. Figure 1: Fairall 9 SED. Left: Best-fit SED obtained with AGNFitter-RX (Martínez-Ramírez et al. 2024). The contributions from the stellar popu￾lation, cold dust emission, torus (CAT3D, Hönig & Kishimoto 2017), accretion disk, and radio components are shown by the yellow, green, purple, dark-blue, and light-blue solid curves, respectively. The shaded regions represent the ranges spanned by 100 random realizations dra… view at source ↗
Figure 2
Figure 2. Figure 2: A schematic representation of the H0RIZON-AGN framework (not to scale). This diagram illustrates the individual components of AGN included in our modeling approach, which collectively contribute to the observed continuum lag-spectrum and broadband SED. atomic features in AGN lag-spectra, which are naturally ex￾plained by diffuse BLR continuum emission (Korista & Goad 2001; Lawther et al. 2018). Additional … view at source ↗
Figure 3
Figure 3. Figure 3: Representative BLR properties of Fairall 9 from FRADO. Left: 3-D distribution of BLR cloud positions inferred from the FRADO model, assuming MBH = 2.18 × 108 M⊙, ˙m = 0.0316 (one of the three adopted accretion rates), and metallicity Z = 5 in solar unit. The axes are given in units of rg. Middle: 2-D velocity–delay map of Fairall 9 constructed from the FRADO model for an inclination angle of i = 35◦ . The … view at source ↗
Figure 4
Figure 4. Figure 4: Emissivity profiles. BLR emissivity profile (ratio of the repro￾cessed to the incident continuum) of a BLR cloud centered at log r (cm) = 16.64, with an incident ionizing luminosity of log L (erg/s) = 44.97, a hydrogen density of log nH (cm−3 ) = 12, a column density of log NH (cm−2 ) = 23.5, and fBLR = 1, shown by the solid red line computed us￾ing Cloudy. The corresponding dust emissivity profile, assumi… view at source ↗
Figure 5
Figure 5. Figure 5: Transfer functions of the different emitting regions in the central parts of Fairall 9 for the best-fit luminosity distance, DL = 190.6 Mpc. From left to right: (i) the transfer function of the warm corona; (ii) transfer functions of the cold accretion disk at different wavelengths, with the wavelength-integrated disk response function shown by the black line; (iii) the BLR response function obtained from … view at source ↗
Figure 6
Figure 6. Figure 6: Total transfer functions, ψtot(λ, t), at different wavelengths. The color coding follows the wavelength labels. The wavelength-integrated total transfer function, ψtot(t), is plotted as the black curve for illustrative purposes. Parameters used: MBH = 2.18 × 108M⊙, Eddington ratio ˙m = 0.0224, LX = 6.74 × 1044 erg s−1 , h = 11.26 rg, TWC = 4.58 × 106 K, τWC = 22.08, rtransition = 252.38 rg, rout = 10000 rg… view at source ↗
Figure 8
Figure 8. Figure 8: Best fit of the broadband SED of Fairall 9 for luminosity dis￾tance, DL = 190.6 Mpc. The observational data are marked in black, the total model in red, the components of the model are the following: warm corona (orange), cold outer disk (blue), BLR and Fe II (green), dusty torus(peru), and starlight (brown). 4.8. Distance estimation via simultaneous lag-spectrum and SED fitting In our model, we fixed MBH,… view at source ↗
Figure 9
Figure 9. Figure 9: Simultaneous lag-spectrum and SED fitting results for Fairall 9. Top: Best-fit χ 2 /dof as a function of the luminosity distance, DL, marginalized over all other model parameters. Bottom: Same as the top panel, but shown as a function of the inferred Hubble constant, H0. The red dashed and black dashed curves represent spline and quartic fits, respectively, to the data shown as red circular points. The ver… view at source ↗
read the original abstract

The Hubble tension remains one of the most significant unresolved problems in modern cosmology. A key question is whether it may arise from underestimated systematic uncertainties in the different measurement techniques. In this context, new independent methods are of exceptional importance. We therefore pursue a novel approach to determining the Hubble constant, $H_{0}$ based on continuum time delay and spectral energy distribution (SED) modeling in active galactic nuclei (AGNs). Unlike conventional techniques, this method is entirely independent of the cosmic distance ladder and does not require cross-calibration against other distance indicators. As a result, it enables a direct determination of $H_{0}$, free from the arbitrary normalizations that often affect indirect measurements. We conducted a dedicated monitoring campaign of the Seyfert galaxy Fairall 9 and further developed the {\tt H0RIZON-AGN} model to interpret the resulting observations. The model incorporates the effects of radiation reprocessing in the surrounding cold accretion disk, enabling a more realistic description of the observed continuum delays. Through the simultaneous modeling of the continuum lag-spectrum and the broadband SED of Fairall 9, we derived a Hubble constant of $H_{0}=72.4_{-3.7}^{+3.4} \, \rm km \, s^{-1} \, Mpc^{-1}$. Achieving a measurement precision of approximately 5% from a single source demonstrates the considerable potential of this method for independent determinations of the Hubble constant. Our determination of $H_{0}$ is broadly consistent, within the current uncertainties, with both early- and late-Universe measurements. Future applications of the method to larger datasets, particularly those provided by the Vera Rubin Observatory, are expected to reduce the uncertainty to below 1%, thereby establishing this approach as a powerful independent probe of the Hubble tension.

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

1 major / 1 minor

Summary. The manuscript presents a new method to measure the Hubble constant H0 independently of the cosmic distance ladder by jointly fitting the continuum lag spectrum and broadband SED of the Seyfert galaxy Fairall 9 using the H0RIZON-AGN model, which incorporates radiation reprocessing in a cold accretion disk. From a dedicated monitoring campaign, the authors derive H0 = 72.4_{-3.7}^{+3.4} km s^{-1} Mpc^{-1} at approximately 5% precision and note consistency with both early- and late-Universe measurements, with potential for sub-1% precision using larger samples from future surveys.

Significance. If the H0RIZON-AGN model assumptions hold without significant unmodeled systematics, the result provides a genuinely independent cosmological probe at useful precision from a single AGN. The approach avoids cross-calibration issues and could become a valuable addition to Hubble tension studies once applied to larger datasets. The dedicated monitoring and model development are positive steps toward falsifiable, geometry-based distance estimates.

major comments (1)
  1. [H0RIZON-AGN model description and fitting procedure] The central H0 result is obtained by fitting the H0RIZON-AGN model (including luminosity distance via H0) to the observed lags and SED. The model assumes reprocessing occurs only in a standard thin disk with temperature profile and response function fully specified by the free parameters (BH mass, accretion rate, inclination, H0). If Fairall 9 has disk winds, non-standard radial temperature index, or inclination-dependent scattering, the predicted lag spectrum will be offset, biasing the inferred distance (and H0) at a level comparable to the quoted uncertainty. No validation against hydrodynamic simulations or a second AGN with independent geometric distance is reported.
minor comments (1)
  1. [Abstract] The abstract and introduction would benefit from an explicit statement of the key model assumptions (e.g., thin-disk temperature profile, neglect of winds) so readers can immediately assess the scope of the claim.

Simulated Author's Rebuttal

1 responses · 1 unresolved

We thank the referee for their constructive review and for acknowledging the potential of this independent approach to measuring H0. We respond to the major comment below.

read point-by-point responses

  1. Referee: [H0RIZON-AGN model description and fitting procedure] The central H0 result is obtained by fitting the H0RIZON-AGN model (including luminosity distance via H0) to the observed lags and SED. The model assumes reprocessing occurs only in a standard thin disk with temperature profile and response function fully specified by the free parameters (BH mass, accretion rate, inclination, H0). If Fairall 9 has disk winds, non-standard radial temperature index, or inclination-dependent scattering, the predicted lag spectrum will be offset, biasing the inferred distance (and H0) at a level comparable to the quoted uncertainty. No validation against hydrodynamic simulations or a second AGN with independent geometric distance is reported.

    Authors: We agree that the H0RIZON-AGN model is constructed under the standard thin-disk reprocessing assumptions, with the temperature profile and response function set by the free parameters (black-hole mass, accretion rate, inclination, and H0) as described in the manuscript. We acknowledge that unaccounted effects such as disk winds, a non-standard radial temperature index, or inclination-dependent scattering could shift the predicted lag spectrum and thereby bias the inferred luminosity distance and H0 at a level comparable to the reported uncertainty. In the revised manuscript we have added an explicit discussion of these model assumptions and the possible impact of such deviations. Regarding validation, the present work constitutes the first application of the method to a single source. We do not report comparisons against hydrodynamic simulations or against a second AGN possessing an independent geometric distance; such tests lie outside the scope of this initial demonstration and are reserved for future studies with expanded samples. revision: partial

standing simulated objections not resolved
  • Validation of the H0RIZON-AGN model against hydrodynamic simulations or application to a second AGN with an independent geometric distance measurement

Circularity Check

0 steps flagged

No significant circularity; H0 obtained via standard model fit to external data

full rationale

The paper derives H0 by jointly fitting the H0RIZON-AGN model parameters (including distance) to the observed continuum lag spectrum and broadband SED of Fairall 9. This is a direct parameter estimation from independent observational inputs using a physical reprocessing model, not a reduction of the claimed result to its own inputs by construction. No self-definitional equations, fitted subsets renamed as predictions, or load-bearing self-citations appear in the provided text. The method is presented as independent of the distance ladder, with the output H0 value arising from the data fit rather than being presupposed.

Axiom & Free-Parameter Ledger

2 free parameters · 1 axioms · 0 invented entities

Based on the abstract alone, the central claim rests on the validity of the H0RIZON-AGN reprocessing model and the assumption that H0 can be extracted directly from the joint fit without hidden calibrations to other distance indicators. No explicit free parameters beyond the model fit itself are listed.

free parameters (2)
  • H0 = 72.4
    Extracted as the distance parameter that reconciles the physical size implied by lags with the observed flux in the SED fit.
  • accretion-disk model parameters (BH mass, accretion rate, inclination)
    Simultaneously adjusted in the joint lag-spectrum and SED fit.
axioms (1)
  • domain assumption Radiation reprocessing in a cold, standard accretion disk fully accounts for the observed continuum lags and SED shape in Fairall 9.
    Invoked by the H0RIZON-AGN model description in the abstract.

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Reference graph

Works this paper leans on

295 extracted references · 266 canonical work pages · 111 internal anchors

  1. [1]

    , keywords =

    Microlensing of Strongly Lensed Quasars. , keywords =. doi:10.1007/s11214-024-01043-8 , archivePrefix =. 2312.00931 , primaryClass =

    work page doi:10.1007/s11214-024-01043-8

  2. [2]

    Reconciling the Quasar Microlensing Disc Size Problem with a Wind Model of Active Galactic Nucleus

    Reconciling the quasar microlensing disc size problem with a wind model of active galactic nucleus. , keywords =. doi:10.1093/mnras/sty3245 , archivePrefix =. 1806.08496 , primaryClass =

    work page internal anchor Pith review Pith/arXiv arXiv doi:10.1093/mnras/sty3245

  3. [3]

    Gravitational Lensing Size Scales for Quasars

    Gravitational lensing size scales for quasars. Astronomische Nachrichten , keywords =. doi:10.1002/asna.201612313 , archivePrefix =. 1509.05375 , primaryClass =

    work page internal anchor Pith review Pith/arXiv arXiv doi:10.1002/asna.201612313

  4. [4]

    Sizes and Temperature Profiles of Quasar Accretion Disks from Chromatic Microlensing

    Sizes and Temperature Profiles of Quasar Accretion Disks from Chromatic Microlensing. , keywords =. doi:10.1088/0004-637X/729/1/34 , archivePrefix =. 1007.1665 , primaryClass =

    work page internal anchor Pith review Pith/arXiv arXiv doi:10.1088/0004-637x/729/1/34

  5. [5]

    Rubin Observatory Legacy Survey of Space and Time: Source Classification and Galaxy Properties

    Spectral Energy Distributions in Three Deep-drilling Fields of the Vera C. Rubin Observatory Legacy Survey of Space and Time: Source Classification and Galaxy Properties. , keywords =. doi:10.3847/1538-4365/ac7bdf , archivePrefix =. 2206.06432 , primaryClass =

    work page doi:10.3847/1538-4365/ac7bdf

  6. [6]

    , keywords =

    The Sloan Digital Sky Survey Reverberation Mapping Project: Accretion Disk Sizes from Continuum Lags. , keywords =. doi:10.3847/1538-4357/ab2638 , archivePrefix =. 1806.08360 , primaryClass =

    work page doi:10.3847/1538-4357/ab2638

  7. [7]

    , keywords =

    The LSST Era of Supermassive Black Hole Accretion Disk Reverberation Mapping. , keywords =. doi:10.3847/1538-4365/ac88ce , archivePrefix =. 2208.06203 , primaryClass =

    work page doi:10.3847/1538-4365/ac88ce

  8. [8]

    , keywords =

    Modeling the Infrared Reverberation Response of the Circumnuclear Dusty Torus in AGNs: An Investigation of Torus Response Functions. , keywords =. doi:10.3847/1538-4357/ab6aa1 , archivePrefix =. 2002.12823 , primaryClass =

    work page doi:10.3847/1538-4357/ab6aa1 2002

  9. [9]

    Modeling the Infrared Reverberation Response of the Circumnuclear Dusty Torus in AGN: The Effects of Cloud Orientation and Anisotropic Illumination

    Modeling the Infrared Reverberation Response of the Circumnuclear Dusty Torus in AGNs: The Effects of Cloud Orientation and Anisotropic Illumination. , keywords =. doi:10.3847/1538-4357/aa7687 , archivePrefix =. 1709.07011 , primaryClass =

    work page internal anchor Pith review Pith/arXiv arXiv doi:10.3847/1538-4357/aa7687

  10. [10]

    Reverberation Measurements of the Inner Radius of the Dust Torus in Nearby Seyfert 1 Galaxies

    Reverberation Measurements of the Inner Radius of the Dust Torus in Nearby Seyfert 1 Galaxies. , keywords =. doi:10.1086/499326 , archivePrefix =. astro-ph/0511697 , primaryClass =

    work page internal anchor Pith review Pith/arXiv arXiv doi:10.1086/499326

  11. [11]

    and Rodney, Steven and Treu, Tommaso and Oguri, Masamune and Chen, Wenlei and Zitrin, Adi and Birrer, Simon and Bonvin, Vivien and Dessart, Luc and Diego, Jose M

    Kelly, Patrick L. and Rodney, Steven and Treu, Tommaso and Oguri, Masamune and Chen, Wenlei and Zitrin, Adi and Birrer, Simon and Bonvin, Vivien and Dessart, Luc and Diego, Jose M. and Filippenko, Alexei V. and Foley, Ryan J. and others , title =. Science , year =

  12. [12]

    A 2.4 per cent measurement of H _ 0 from lensed quasars: 5.3 tension between early- and late-Universe probes

    H0LiCOW - XIII. A 2.4 per cent measurement of H _ 0 from lensed quasars: 5.3 tension between early- and late-Universe probes. , keywords =. doi:10.1093/mnras/stz3094 , archivePrefix =. 1907.04869 , primaryClass =

    work page doi:10.1093/mnras/stz3094 1907

  13. [13]

    What controls the Fe II strength in active galactic nuclei?

    What Controls the Fe II Strength in Active Galactic Nuclei?. , keywords =. doi:10.1088/0004-637X/736/2/86 , archivePrefix =. 0903.5020 , primaryClass =

    work page internal anchor Pith review Pith/arXiv arXiv doi:10.1088/0004-637x/736/2/86

  14. [14]

    Searching for the Physical Drivers of the Eigenvector 1 Correlation Space

    Searching for the Physical Drivers of the Eigenvector 1 Correlation Space. , keywords =. doi:10.1086/322286 , archivePrefix =. astro-ph/0105343 , primaryClass =

    work page internal anchor Pith review Pith/arXiv arXiv doi:10.1086/322286

  15. [15]

    , keywords =

    Modeling Fe II Emission and Revised Fe II (UV) Empirical Templates for the Seyfert 1 Galaxy I Zw 1. , keywords =. doi:10.1086/525557 , adsurl =

    work page doi:10.1086/525557

  16. [16]

    Reverberation Measurements of the Inner Radius of the Dust Torus in 17 Seyfert Galaxies

    Reverberation Measurements of the Inner Radius of the Dust Torus in 17 Seyfert Galaxies. , keywords =. doi:10.1088/0004-637X/788/2/159 , archivePrefix =. 1406.2078 , primaryClass =

    work page internal anchor Pith review Pith/arXiv arXiv doi:10.1088/0004-637x/788/2/159 2078

  17. [17]

    , keywords =

    Revisiting the Dust Torus Size Luminosity Relation Based on a Uniform Reverberation-mapping Analysis. , keywords =. doi:10.3847/1538-4357/ad414d , archivePrefix =. 2403.01885 , primaryClass =

    work page doi:10.3847/1538-4357/ad414d

  18. [18]

    , keywords =

    Rapid luminosity decline and subsequent reformation of the innermost dust distribution in the changing-look AGN Mrk 590. , keywords =. doi:10.1093/mnras/stz3397 , archivePrefix =. 1904.08946 , primaryClass =

    work page doi:10.1093/mnras/stz3397 1904

  19. [19]

    AGN Dusty Tori. II. Observational Implications of Clumpiness. , keywords =. doi:10.1086/590483 , archivePrefix =. 0806.0512 , primaryClass =

    work page internal anchor Pith review Pith/arXiv arXiv doi:10.1086/590483

  20. [20]

    , keywords =

    Modeling the Central Supermassive Black Hole Mass of Quasars via the LSTM Approach. , keywords =. doi:10.3847/1538-4357/ace03f , archivePrefix =. 2301.01459 , primaryClass =

    work page doi:10.3847/1538-4357/ace03f

  21. [21]

    AGN Dusty Tori. I. Handling of Clumpy Media. , keywords =. doi:10.1086/590482 , archivePrefix =. 0806.0511 , primaryClass =

    work page internal anchor Pith review Pith/arXiv arXiv doi:10.1086/590482

  22. [22]

    , keywords =

    Dust reverberation mapping and light-curve modelling of Zw229-015. , keywords =. doi:10.1093/mnras/stac2529 , archivePrefix =. 2209.01409 , primaryClass =

    work page doi:10.1093/mnras/stac2529

  23. [23]

    Photometric continuum reverberation mapping of Fairall 9

    HALO: I. Photometric continuum reverberation mapping of Fairall 9. , keywords =. doi:10.1051/0004-6361/202557795 , archivePrefix =. 2512.13296 , primaryClass =

    work page doi:10.1051/0004-6361/202557795

  24. [24]

    , keywords =

    Connecting the X-Ray/UV Variability of Fairall 9 with NICER: A Possible Warm Corona. , keywords =. doi:10.3847/1538-4357/ad8dc2 , archivePrefix =. 2410.21432 , primaryClass =

    work page doi:10.3847/1538-4357/ad8dc2

  25. [25]

    Astronomische Nachrichten , keywords =

    Minimum X-ray source size of the on-axis corona in AGN. Astronomische Nachrichten , keywords =. doi:10.1002/asna.201612327 , adsurl =

    work page doi:10.1002/asna.201612327

  26. [26]

    Universal spectral shape of high accretion rate AGN

    Universal spectral shape of high accretion rate AGN. , keywords =. doi:10.1051/0004-6361:20031441 , archivePrefix =. astro-ph/0309242 , primaryClass =

    work page internal anchor Pith review Pith/arXiv arXiv doi:10.1051/0004-6361:20031441

  27. [27]

    , keywords =

    X-ray view of dissipative warm corona in active galactic nuclei. , keywords =. doi:10.1051/0004-6361/202450111 , archivePrefix =. 2406.14378 , primaryClass =

    work page doi:10.1051/0004-6361/202450111

  28. [28]

    , keywords =

    The broad-band view of the bare Seyfert PG 1426+015: relativistic reflection, the soft excess, and the importance of oxygen. , keywords =. doi:10.1093/mnras/staf1545 , archivePrefix =. 2509.13411 , primaryClass =

    work page doi:10.1093/mnras/staf1545

  29. [29]

    Two per cent measurement of $H_0$ from Cepheids alone

    1.8 per cent measurement of H _ 0 from Cepheids alone. , keywords =. doi:10.1093/mnras/staf2260 , archivePrefix =. 2509.09665 , primaryClass =

    work page internal anchor Pith review Pith/arXiv arXiv doi:10.1093/mnras/staf2260

  30. [30]

    arXiv e-prints , keywords =

    The subtle statistics of the distance ladder: On the distance prior and selection effects. arXiv e-prints , keywords =. doi:10.48550/arXiv.2511.03394 , archivePrefix =. 2511.03394 , primaryClass =

    work page doi:10.48550/arxiv.2511.03394

  31. [31]

    , keywords =

    The Manticore Project I: a digital twin of our cosmic neighbourhood from Bayesian field-level analysis. , keywords =. doi:10.1093/mnras/staf767 , archivePrefix =. 2505.10682 , primaryClass =

    work page doi:10.1093/mnras/staf767

  32. [32]

    , keywords =

    Unveiling energy pathways in AGN accretion flows with the warm corona model for the soft excess. , keywords =. doi:10.1093/mnras/stae944 , archivePrefix =. 2404.03040 , primaryClass =

    work page doi:10.1093/mnras/stae944

  33. [33]

    arXiv e-prints , keywords =

    The Binary Ballet: Mapping Local Expansion Around M81 & M82. arXiv e-prints , keywords =. doi:10.48550/arXiv.2510.24840 , archivePrefix =. 2510.24840 , primaryClass =

    work page doi:10.48550/arxiv.2510.24840

  34. [34]

    Alignment with DESI BAO and signs of a non-accelerating universe

    Strong progenitor age bias in supernova cosmology ─ II. Alignment with DESI BAO and signs of a non-accelerating universe. , keywords =. doi:10.1093/mnras/staf1685 , archivePrefix =. 2510.13121 , primaryClass =

    work page doi:10.1093/mnras/staf1685

  35. [35]

    The Local Distance Network: a community consensus report on the measurement of the Hubble constant at 1% precision

    The Local Distance Network: a community consensus report on the measurement of the Hubble constant at 1\. arXiv e-prints , keywords =. doi:10.48550/arXiv.2510.23823 , archivePrefix =. 2510.23823 , primaryClass =

    work page internal anchor Pith review Pith/arXiv arXiv doi:10.48550/arxiv.2510.23823

  36. [36]

    The Seoul National University AGN Monitoring Project. III. H Lag Measurements of 32 Luminous Active Galactic Nuclei and the High-luminosity End of the Size Luminosity Relation. , keywords =. doi:10.3847/1538-4357/ad132f , archivePrefix =. 2311.15518 , primaryClass =

    work page doi:10.3847/1538-4357/ad132f

  37. [37]

    arXiv e-prints , keywords =

    The Disk Plus (Failed) Wind System of 3C 47: A Story of Accretion Disks and Binary Black Holes. arXiv e-prints , keywords =. doi:10.48550/arXiv.2510.01972 , archivePrefix =. 2510.01972 , primaryClass =

    work page doi:10.48550/arxiv.2510.01972

  38. [38]

    Cosmology with supernova Encore in the strong lensing cluster MACS J0138-2155: Lens model comparison and H0 measurement

    Cosmology with supernova Encore in the strong lensing cluster MACS J0138-2155: Lens model comparison and H0 measurement. arXiv e-prints , keywords =. doi:10.48550/arXiv.2509.12319 , archivePrefix =. 2509.12319 , primaryClass =

    work page internal anchor Pith review Pith/arXiv arXiv doi:10.48550/arxiv.2509.12319

  39. [39]

    , keywords =

    Reflection Features in the X-Ray Spectrum of Fairall 9 and Implications for Tests of General Relativity. , keywords =. doi:10.3847/1538-4357/ab917a , archivePrefix =. 2004.11542 , primaryClass =

    work page doi:10.3847/1538-4357/ab917a 2004

  40. [40]

    J., Johnston, S., Ray, P

    An XMM-Newton view of the `bare' nucleus of Fairall 9. , keywords =. doi:10.1111/j.1365-2966.2011.18834.x , archivePrefix =. 1104.0044 , primaryClass =

    work page doi:10.1111/j.1365-2966.2011.18834.x 2011

  41. [41]

    , keywords =

    Broad line region and black hole mass of PKS 1510-089 from spectroscopic reverberation mapping. , keywords =. doi:10.1051/0004-6361/202038324 , archivePrefix =. 2007.07672 , primaryClass =

    work page doi:10.1051/0004-6361/202038324 2007

  42. [42]

    X-ray/UV/optical variability of NGC 4593 with Swift: Reprocessing of X-rays by an extended reprocessor

    X-ray/UV/optical variability of NGC 4593 with Swift: reprocessing of X-rays by an extended reprocessor. , keywords =. doi:10.1093/mnras/sty1983 , archivePrefix =. 1712.04852 , primaryClass =

    work page internal anchor Pith review Pith/arXiv arXiv doi:10.1093/mnras/sty1983

  43. [43]

    Supermassive Black Holes with High Accretion Rates in Active Galactic Nuclei. VIII. Structure of the Broad-line Region and Mass of the Central Black Hole in Mrk 142. , keywords =. doi:10.3847/1538-4357/aaee6b , archivePrefix =. 1811.06302 , primaryClass =

    work page internal anchor Pith review Pith/arXiv arXiv doi:10.3847/1538-4357/aaee6b

  44. [44]

    Reverberation Mapping Measurements of Black Hole Masses in Six Local Seyfert Galaxies

    Reverberation Mapping Measurements of Black Hole Masses in Six Local Seyfert Galaxies. , keywords =. doi:10.1088/0004-637X/721/1/715 , archivePrefix =. 1006.4160 , primaryClass =

    work page internal anchor Pith review Pith/arXiv arXiv doi:10.1088/0004-637x/721/1/715

  45. [45]

    , keywords =

    UV-Optical Disk Reverberation Lags despite a Faint X-Ray Corona in the Active Galactic Nucleus Mrk 335. , keywords =. doi:10.3847/1538-4357/acbcd3 , archivePrefix =. 2302.07342 , primaryClass =

    work page doi:10.3847/1538-4357/acbcd3

  46. [46]

    AGN STORM 2. XII. Ground-based Optical Photometry and Lag Measurements of Mrk 817. , keywords =. doi:10.3847/1538-4357/ae6103 , archivePrefix =. 2605.02875 , primaryClass =

    work page internal anchor Pith review Pith/arXiv arXiv doi:10.3847/1538-4357/ae6103

  47. [47]

    , keywords =

    Accretion disc reverberation mapping in a high-redshift quasar. , keywords =. doi:10.1051/0004-6361/202555421 , archivePrefix =. 2508.00209 , primaryClass =

    work page doi:10.1051/0004-6361/202555421

  48. [48]

    , keywords =

    The unusually red delay spectrum of the low-mass black hole AGN NGC 4051 as revealed by intensive continuum reverberation mapping with the Las Cumbres Observatory. , keywords =. doi:10.1093/mnras/stag642 , archivePrefix =. 2604.01405 , primaryClass =

    work page doi:10.1093/mnras/stag642

  49. [49]

    , keywords =

    Continuum Reverberation Mapping of Mrk 876 over Three Years with Remote Robotic Observatories. , keywords =. doi:10.3847/1538-4357/ace342 , archivePrefix =. 2307.02630 , primaryClass =

    work page doi:10.3847/1538-4357/ace342

  50. [50]

    , keywords =

    Testing super-eddington accretion on to a supermassive black hole: reverberation mapping of PG 1119+120. , keywords =. doi:10.1093/mnras/stad1409 , archivePrefix =. 2302.09370 , primaryClass =

    work page doi:10.1093/mnras/stad1409

  51. [51]

    , keywords =

    On the nature of the continuum reverberation of X-ray/UV and optical emission of IRAS 09149-6206. , keywords =. doi:10.1093/mnras/stad2483 , archivePrefix =. 2308.05433 , primaryClass =

    work page doi:10.1093/mnras/stad2483

  52. [52]

    Photometric reverberation mapping of 3C120

    Photometric reverberation mapping of 3C 120. , keywords =. doi:10.1051/0004-6361/201219107 , archivePrefix =. 1303.3506 , primaryClass =

    work page internal anchor Pith review Pith/arXiv arXiv doi:10.1051/0004-6361/201219107

  53. [53]

    arXiv e-prints , keywords =

    Departures from Standard Disk Predictions in Intensive Ground-Based Monitoring of Three AGN. arXiv e-prints , keywords =

  54. [54]

    Steps toward Determination of the Size and Structure of the Broad-Line Region in Active Galactic Nuclei. X. Variability of Fairall 9 from Optical Data. , keywords =. doi:10.1086/313046 , adsurl =

    work page doi:10.1086/313046

  55. [55]

    Steps toward Determination of the Size and Structure of the Broad-Line Region in Active Galactic Nuclei. IX. Ultraviolet Observations of Fairall 9. , keywords =. doi:10.1086/312996 , adsurl =

    work page doi:10.1086/312996

  56. [56]

    , keywords =

    Revisiting the H Size Luminosity Relation Using a Uniform Reverberation-mapping Analysis. , keywords =. doi:10.3847/1538-4365/ad74f2 , archivePrefix =. 2408.15872 , primaryClass =

    work page doi:10.3847/1538-4365/ad74f2

  57. [57]

    , keywords =

    The Size of the Continuum Emission Region and Its Scaling Relations with Active Galactic Nucleus Luminosity and the Broad-line Region Size. , keywords =. doi:10.3847/1538-4357/adc56e , archivePrefix =. 2502.19184 , primaryClass =

    work page doi:10.3847/1538-4357/adc56e

  58. [58]

    Modeling the Time Variability of SDSS Stripe 82 Quasars as a Damped Random Walk

    Modeling the Time Variability of SDSS Stripe 82 Quasars as a Damped Random Walk. , keywords =. doi:10.1088/0004-637X/721/2/1014 , archivePrefix =. 1004.0276 , primaryClass =

    work page internal anchor Pith review Pith/arXiv arXiv doi:10.1088/0004-637x/721/2/1014

  59. [59]

    , keywords =

    Bayesian analysis of quasar light curves with a running optimal average: new time delay measurements of COSMOGRAIL gravitationally lensed quasars. , keywords =. doi:10.1093/mnras/stab2832 , archivePrefix =. 2107.12318 , primaryClass =

    work page doi:10.1093/mnras/stab2832

  60. [62]

    Central Masses and Broad-Line Region Sizes of Active Galactic Nuclei. I. Comparing the Photoionization and Reverberation Techniques. , eprint =. doi:10.1086/308017 , adsurl =

    work page doi:10.1086/308017

  61. [63]

    PyCCF: Python Cross Correlation Function for reverberation mapping studies

  62. [64]

    On Uncertainties in Cross-Correlation Lags and the Reality of Wavelength-Dependent Continuum Lags in Active Galactic Nuclei

    On Uncertainties in Cross-Correlation Lags and the Reality of Wavelength-dependent Continuum Lags in Active Galactic Nuclei. , keywords =. doi:10.1086/316177 , archivePrefix =. astro-ph/9802103 , primaryClass =

    work page internal anchor Pith review Pith/arXiv arXiv doi:10.1086/316177

  63. [65]

    , keywords =

    The accuracy of cross-correlation estimates of quasar emission-line region sizes. , keywords =. doi:10.1086/191216 , adsurl =

    work page doi:10.1086/191216

  64. [66]

    , keywords =

    Line variations in quasars and Seyfert galaxies. , keywords =. doi:10.1086/164238 , adsurl =

    work page doi:10.1086/164238

  65. [67]

    , keywords =

    Disentangling the optical AGN and host-galaxy luminosity with a probabilistic flux variation gradient. , keywords =. doi:10.1051/0004-6361/202141710 , archivePrefix =. 2109.03619 , primaryClass =

    work page doi:10.1051/0004-6361/202141710

  66. [68]

    Nature Astronomy , year = 2019, month = jan, volume =

    Direct evidence of non-disk optical continuum emission around an active black hole. Nature Astronomy , year = 2019, month = jan, volume =. doi:10.1038/s41550-018-0659-x , adsurl =

    work page doi:10.1038/s41550-018-0659-x 2019

  67. [69]

    Long-Term Optical Continuum Color Variability of Nearby Active Galactic Nuclei

    Long-Term Optical Continuum Color Variability of Nearby Active Galactic Nuclei. , keywords =. doi:10.1088/0004-637X/711/1/461 , archivePrefix =. 1001.5162 , primaryClass =

    work page internal anchor Pith review Pith/arXiv arXiv doi:10.1088/0004-637x/711/1/461

  68. [70]

    Automatized photometric monitoring of active galactic nuclei with the 46 cm telescope of the Wise observatory

    Automatized Photometric Monitoring of Active Galactic Nuclei with the 46cm Telescope of the Wise Observatory. , keywords =. doi:10.1088/1538-3873/aa7a55 , archivePrefix =. 1706.05463 , primaryClass =

    work page internal anchor Pith review Pith/arXiv arXiv doi:10.1088/1538-3873/aa7a55

  69. [71]

    Maps of Dust IR Emission for Use in Estimation of Reddening and CMBR Foregrounds

    Maps of Dust Infrared Emission for Use in Estimation of Reddening and Cosmic Microwave Background Radiation Foregrounds. , keywords =. doi:10.1086/305772 , archivePrefix =. astro-ph/9710327 , primaryClass =

    work page internal anchor Pith review Pith/arXiv arXiv doi:10.1086/305772

  70. [72]

    F., & Finkbeiner, D

    Measuring Reddening with Sloan Digital Sky Survey Stellar Spectra and Recalibrating SFD. , keywords =. doi:10.1088/0004-637X/737/2/103 , archivePrefix =. 1012.4804 , primaryClass =

    work page internal anchor Pith review Pith/arXiv arXiv doi:10.1088/0004-637x/737/2/103

  71. [73]

    Optical atmospheric extinction over Cerro Paranal

    Optical atmospheric extinction over Cerro Paranal. , keywords =. doi:10.1051/0004-6361/201015537 , archivePrefix =. 1011.6156 , primaryClass =

    work page internal anchor Pith review Pith/arXiv arXiv doi:10.1051/0004-6361/201015537

  72. [74]

    Space Telescope and Optical Reverberation Mapping Project. III. Optical Continuum Emission and Broadband Time Delays in NGC 5548. , keywords =. doi:10.3847/0004-637X/821/1/56 , archivePrefix =. 1510.05648 , primaryClass =

    work page internal anchor Pith review Pith/arXiv arXiv doi:10.3847/0004-637x/821/1/56

  73. [75]

    V., & Jenkins, A

    On characterizing the variability properties of X-ray light curves from active galaxies. , keywords =. doi:10.1046/j.1365-2966.2003.07042.x , archivePrefix =. astro-ph/0307420 , primaryClass =

    work page doi:10.1046/j.1365-2966.2003.07042.x 2003

  74. [76]

    , keywords =

    Estimation of the size and structure of the broad line region using Bayesian approach. , keywords =. doi:10.1093/mnras/stab012 , archivePrefix =. 2101.00802 , primaryClass =

    work page doi:10.1093/mnras/stab012

  75. [77]

    , eprint =

    X-Ray Spectral Variability and Rapid Variability of the Soft X-Ray Spectrum Seyfert 1 Galaxies Arakelian 564 and Ton S180. , eprint =. doi:10.1086/323779 , adsurl =

    work page doi:10.1086/323779

  76. [78]

    AGN Coronae Through A Jet Perspective

    AGN Coronae through a Jet Perspective. , keywords =. doi:10.3847/1538-4357/835/2/226 , archivePrefix =. 1612.07784 , primaryClass =

    work page internal anchor Pith review Pith/arXiv arXiv doi:10.3847/1538-4357/835/2/226

  77. [79]

    M., Osipov, S

    Broad-line region physical conditions along the quasar eigenvector 1 sequence. , keywords =. doi:10.1111/j.1365-2966.2010.17357.x , archivePrefix =. 1007.3187 , primaryClass =

    work page doi:10.1111/j.1365-2966.2010.17357.x 2010

  78. [80]

    , keywords =

    Estimating black hole masses: Accretion disk fitting versus reverberation mapping and single epoch. , keywords =. doi:10.1051/0004-6361/201936218 , archivePrefix =. 1907.00986 , primaryClass =

    work page doi:10.1051/0004-6361/201936218 1907

  79. [81]

    arXiv e-prints , keywords =

    Temperature Fluctuations in Quasar Accretion Discs from Spectroscopic Monitoring Data. arXiv e-prints , keywords =

  80. [82]

    , keywords =

    Negative Lags on the Viscous Timescale in Quasar Photometry and Prospects for Detecting More with LSST. , keywords =. doi:10.3847/1538-4357/ace7d2 , archivePrefix =. 2306.05455 , primaryClass =

    work page doi:10.3847/1538-4357/ace7d2

Showing first 80 references.