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Time-evolving Diagnostic of the Ionized Absorbers in NGC 4051. II. High-throughput Time-resolved Spectroscopy

T0 review · 3 major / 4 minor · reviewed 2026-08-01 · deepseek-v4-flash

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Pith's one-line read By tracking how ion absorption lines lag a hard X-ray flare across 37 time-resolved spectra, this paper fixes the main warm absorber in NGC 4051 at about 10^4 gravitational radii and breaks the density-distance degeneracy.

desk verdict Careful, high-throughput application of time-evolving photoionization that plausibly locates NGC 4051's warm absorbers, but the result hinges on a rigid SED driver that ignores the measured spectral-index variability. read the letter →

arxiv 2607.20621 v1 pith:UKXLXQLK submitted 2026-07-22 astro-ph.HE astro-ph.GA

Alfredo Luminari , Fabrizio Nicastro , Roberto Serafinelli , Riccardo Middei , Yair Krongold , Elias Kammoun , Luigi Piro , Francesca Diaferia This is my paper · ORCID
classification astro-ph.HEastro-ph.GA
keywords AGNSeyfertgalaxywarmabsorberstime-resolvedspectroscopyphotoionisationdensity-distancedegeneracyoutflowenergeticsX-rayvariability
verification ladder T0 review T1 audit T2 compute T3 formal

The pith

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

The reading

The paper sets out to break the degeneracy between number density and radial distance that has long blocked reliable measurements of AGN outflow energetics. It does so by treating the ionization of three known absorbers in NGC 4051 as time-dependent: a joint 160 ksec observation is split into 37 spectra, and the Time-Evolving PhotoIonisation Device (TEPID) predicts how ionic columns should lag the observed continuum variability for different densities. The key result is a fully constrained density for the most opaque, intermediate-ionization absorber, log n_e = 7.0(+0.5/-0.2) cm^-3, which translates through the ionization parameter into a distance of about 10^4 gravitational radii, inside the broad-line region. Upper and lower limits place the other two absorbers at <600 r_G and at >=3.8x10^5 r_G, respectively, and the total energy outflow rate comes out below 10^-4 of the bolometric luminosity, too weak to drive galaxy-scale feedback. If this holds, time-evolving photoionisation becomes a practical way to locate nuclear outflows and weigh their impact.

What carries the argument

The central object is TEPID, a time-evolving photoionisation code that tracks how ionic abundances and temperature respond to a time-variable ionising continuum. The key identity is the equilibration timescale, t_eq proportional to 1/n_e, which converts the observed lag between continuum changes and absorption-line changes into a density measurement; combining that density with the ionization parameter through r = sqrt(Q_ion / (4 pi U n_H c)) then gives the distance. The analysis fits 37 simultaneously analysed soft and hard X-ray spectra with ionic columns predicted by TEPID, so the shape of the lag directly selects n_e over a grid spanning 10^5 to 10^10 cm^-3.

What would settle it

Take another long, bright X-ray observation of NGC 4051 during a different variability pattern and repeat the same TEPID fit: the gas density is a physical property, so the HIP should again come out near log n_e about 7.0 cm^-3. A significantly different best-fit density would indicate the inferred radius depends on the assumed SED scaling rather than on the gas itself.

Watch

Extended reading notes

Core claim

The central claim is that the highest-opacity, intermediate-ionisation absorber (HIP) in NGC 4051 has a fully constrained electron density and radius: log(n_e/cm^-3) = 7.0(+0.5/-0.2) and r = (10.1+0.8/-0.3) x 10^3 r_G. That radius puts the gas inside the broad-line region, aligned with the He II-emitting zone and the soft X-ray emission lines. The fastest, most ionised component lies within 600 r_G, matching the broad Fe K-alpha line, and the slowest, least ionised component lies at >=3.8 x 10^5 r_G, near the torus and narrow Fe K-alpha. The same fit gives a total outflow energy rate below 10^-4 of the bolometric luminosity, so these winds cannot provide significant mechanical feedback to th

Load-bearing premise

The load-bearing premise is that the ionising continuum's variability is fully tracked by the hard X-ray 3-6 keV lightcurve on which the entire SED is rigidly scaled, and that each absorber is a single uniform-density cloud; if the EUV or soft X-ray ionising flux varies with a different pattern or the clouds are structured, the inferred densities and radii will be biased.

Editorial extensions

If this is right

  • The HIP density and distance are fixed: log n_e = 7.0(+0.5/-0.2) cm^-3 and r about 10^4 r_G, placing it inside the BLR and cospatial with the soft X-ray emission lines.
  • The HVIP must lie within 600 r_G, matching the broad Fe K-alpha component, while the LIP must lie beyond 3.8 x 10^5 r_G, matching the torus and narrow Fe K-alpha.
  • The total energy outflow rate is below 10^-4 of the bolometric luminosity, so these warm absorbers do not provide significant mechanical feedback to the host galaxy.
  • Because the observed absorber velocities are below the escape velocity at their measured radii, the outflows are likely bound 'failed winds' unless the line of sight strongly underestimates the true, more vertical velocities.
  • The method demonstrates that time-evolving photoionisation applied to high-throughput time-resolved spectroscopy can break the n_e-r degeneracy, opening a route to locating and weighing nuclear outflows in other bright variable AGNs.

Reading between the lines

Editorial extensions of the paper, not claims the author makes directly.

  • If the hard-band lightcurve scaling assumption is violated, and the EUV or soft X-ray ionising continuum varies with a different pattern or lag, the derived densities and radii across all three absorbers could shift systematically; a simultaneous high-cadence EUV or soft X-ray lightcurve would test this directly.
  • The same ionization-lag technique could be applied to ultraviolet absorption lines in NGC 4051, monitoring C IV and N V variability with comparable cadence, to check whether the low-ionisation absorber responds at the same distance claimed here.
  • The inferred co-location of the three absorbers with the broad Fe K-alpha, the BLR, and the torus suggests a single stratified wind rather than three independent clouds; a testable consequence is that absorber columns and velocities should vary coherently on timescales set by their respective radii if the continuum changes.
  • If this energy budget generalises, slow warm absorbers in similar Seyferts are unlikely to be the main AGN feedback channel, so searches for mechanical feedback should focus on ultra-fast outflows, radio jets, or other more energetic components.
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Editorial analysis

A structured set of objections, weighed in public.

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

Referee Report

3 major / 4 minor

Summary. The paper applies the time-evolving photoionisation code TEPID to 37 time-resolved XMM-Newton EPIC-pn and NuSTAR spectra of NGC 4051, jointly fitting three ionised absorbers (LIP, HIP, HVIP) with column densities and velocities fixed to the time-averaged RGS values from Paper I. The key result is a fully constrained density and radius for the HIP: log(n_e/cm^-3) = 7.0(+0.5,-0.2) and r = (10.1^+0.8_-0.3) × 10^3 r_G, derived from the fitted U_0 and n_e through Eq. (1). Upper/lower limits are placed on the other absorbers, and the total outflow energy rate is reported below 10^-4 L_bol, with locations compared to BLR, torus, and Fe Kα components.

Significance. If the density-radius result is robust, this is a valuable demonstration of time-resolved spectroscopy as a tool to break the density-distance degeneracy in AGN outflows, with the HIP position tied to the BLR and the HVIP to the broad Fe Kα region. The analysis is unusually detailed: TEPID is cross-checked against Cloudy (Figs. 2–3), the continuum is constrained with simultaneous XMM and NuSTAR, and the derived locations are externally consistent with independent BLR/torus estimates. However, the central HIP constraint rests on assumptions about the driving SED and on fixed column densities; these need to be tested before the result can be taken at face value.

major comments (3)
  1. [§3.2, §4.1, Eq. (1)] The TEPID input SED is scaled rigidly according to the NuSTAR 3–6 keV lightcurve, while the spectral fits allow Γ to vary freely and find a strong Γ–F correlation (Fig. 6). For a power-law continuum, a change ΔΓ=0.2 at fixed 3–6 keV flux changes the ionizing photon rate at ~0.5 keV by a factor ~1.5, so the assumed driving lightcurve can differ substantially from the true one. Since n_e is inferred from the response lag of the ionic columns, this systematic is not included in the quoted errors. Please repeat the TEPID fit using the measured Γ(t) as an additional driver, or provide a sensitivity analysis bounding the systematic on log n_e.
  2. [§4.1] N_H and v_out are fixed to the time-averaged RGS values for all three absorbers. If the columns or covering fractions vary over the 160 ks, the time-dependent optical depth changes would be absorbed into n_e, biasing the density estimate. The paper does not test this assumption. At minimum, a check with N_H free in a subset of bins, or a discussion of why column variability is negligible, is needed.
  3. [Table 1] The global χ²/dof = 10140.5/15633 = 0.65 is far below unity and is not commented on. This may indicate overestimated errors or model flexibility, which would affect the reliability of the reported 1σ contours for log n_e. The authors should discuss the statistic and, if appropriate, rescale errors or use a statistic better matched to the data.
minor comments (4)
  1. [Fig. 10 caption] Typo: 'soposnds' should be 'corresponds'.
  2. [§5.1] The escape velocity formula is written as sqrt(2GM⊙/r); the mass should be the black hole mass M_BH, not the solar mass, since the context is the gravitational potential of the black hole.
  3. [§2.1] The text refers to the NuSTAR 3–79 keV lightcurve, but the TEPID driver uses the 3–6 keV lightcurve. The identity is reasonable, but the wording is slightly confusing; please clarify which lightcurve is used and why the hard band is a good proxy.
  4. [§3.2] The sentence 'It must be noted that similar results ... would be obtained by scaling rigidly the whole SED' addresses only a normalization choice, not the spectral-shape variability discussed in Major Comment 1. Please rephrase to avoid implying that this comparison rules out Γ-driven systematics.

Circularity Check

0 steps flagged · score 1.0 of 10

No significant circularity: the HIP density is a genuinely fitted temporal-response parameter, and the radius follows algebraically from the definition of U; self-citations are for code validation and prior measurements, not load-bearing.

full rationale

The derivation chain is: (i) the 37 time-resolved EPIC-pn/NuSTAR spectra are fitted with PHASE+TEPID models; (ii) n_e enters as a free parameter controlling the ionic response lag through t_eq / 1/n_e; (iii) the HIP density log n_e = 7.0(+0.5,-0.2) is determined by chi^2 minimization; (iv) r is then computed from Eq. 1, r = sqrt(Q_ion/(4 pi U n_H c)), which is the definition of the ionization parameter, not an independent prediction. This is standard inference: the density is constrained by a different observable (the timescale of ionic-column variability), so the density-distance degeneracy is genuinely broken rather than reproduced. The BLR/torus/Fe K-alpha coincidences quoted in Table 2 come from independent literature or from Paper I (RGS absorption measurements); they are external consistency checks, not inputs that force n_e or r. The f_U initial over/under-ionization parameter is allowed to vary but converges to 1.0 +/- 0.2, so the result does not depend on the initial condition. Self-citations (TEPID, Paper I, Nicastro et al. 1999, K07) are used for code description, previous measurements, and the standard t_eq relation; the code is also validated against Cloudy in Figs. 2-3. The main caveat - a rigidly scaled NuSTAR 3-6 keV SED driver while Gamma(t) varies in the continuum fits - is a systematic modeling assumption that could bias n_e, but it is not a circular reduction of the result to its inputs. No step in the paper makes the derived n_e or r equal, by construction, to a fitted parameter or to a self-cited claim.

Assumptions & free parameters 8 free parameters · 5 assumptions · 0 invented entities

The central claim rests on fitted U_0 and n_e for the three absorbers, plus the SED-driving and single-zone assumptions. No new physical entities are introduced; TEPID is a numerical code, not a new particle or force.

free parameters (8)
  • log(U0)_HIP = 1.57 (+0.01/−0.02)
    Fitted initial ionization parameter of the HIP absorber (Table 1); sets the ionization level that, with n_e, determines distance via Eq. 1.
  • log(n_e)_HIP = 7.0 (+0.5/−0.2)
    Fitted electron number density of the HIP absorber (Table 1); the central measured quantity, controls the recombination timescale.
  • log(U0)_LIP = −0.03 (+0.05/−0.06)
    Fitted ionization parameter of the slow, low-ionization absorber (Table 1).
  • log(n_e)_LIP = <5.5
    Upper limit on density of LIP; sets the lower limit on its distance.
  • log(U0)_HVIP = 2.37 (+0.07/−0.03)
    Fitted ionization parameter of the fast, high-ionization absorber (Table 1).
  • log(n_e)_HVIP = >8.7
    Lower limit on density of HVIP; sets upper limit on its distance.
  • f_U = 1.0 ± 0.2
    Initial over/under-ionisation factor, linked across the three absorbers; converges to unity (Sect. 4.3).
  • Continuum parameters (Γ, kT, bb norm, xillver norm) = e.g., Γ: 1.83±0.02; kT: 98.9±0.4 eV; xillver norm Obs1 1.25±0.03, Obs2 0.67±0.03 (Table 1)
    Fitted continuum shapes the SED that drives TEPID; uncertainties in these propagate into U0 and n_e, though not directly into the central density value.
assumptions (5)
  • domain assumption The recombination/ionization equilibrium timescale is inversely proportional to electron density (t_eq ∝ 1/n_e).
    Used to break the density–distance degeneracy (Sect. 1, Eq. 1). Standard atomic-physics result from Krolik & Kriss 1995 and Nicastro et al. 1999.
  • domain assumption The ionizing continuum variability is tracked by the NuSTAR 3-6 keV lightcurve; the SED is scaled rigidly above 0.3 keV.
    Sect. 3.2, SED construction. If the EUV/soft X-ray ionizing flux varies with a different pattern or lag, the inferred n_e is biased.
  • domain assumption Each absorber is a single-zone, homogeneous slab with uniform density and no density gradient or covering-factor evolution.
    TEPID models one-zone gas (Sect. 3); the time-resolved fitting assumes constant N_H and v_out from RGS (Sect. 4.1).
  • domain assumption Photoionization equilibrium at t=0, with possible f_U scaling.
    Sect. 3.1; f_U is fitted and equals 1, so the initial state is consistent with equilibrium.
  • domain assumption TEPID atomic data and radiative transfer are sufficiently accurate.
    Validated against Cloudy in Figs. 2–3; residual discrepancies for S and Fe are noted.

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Pith. "Pith review of Time-evolving Diagnostic of the Ionized Absorbers in NGC 4051. II. High-throughput Time-resolved Spectroscopy." pith.science (2026). https://pith.science/paper/UKXLXQLK

@misc{pith2026260720621,
  author       = {Pith},
  title        = {Pith review of: Time-evolving Diagnostic of the Ionized Absorbers in NGC 4051. II. High-throughput Time-resolved Spectroscopy},
  year         = {2026},
  howpublished = {\url{https://pith.science/paper/UKXLXQLK}},
  note         = {Machine review of arXiv:2607.20621}
}
abstract

Active Galactic Nuclei (AGNs) are one of the most powerful sources in the Universe. The accretion-liberated energy can strongly impact the surrounding environment, up to the host galaxy and beyond. Notwithstanding their ubiquitous presence, nuclear outflows are poorly characterised, mainly due to the degeneracy between their number density $n_e$ and radial location $r$, intrinsic in the photoionisation equilibrium models which are usually employed to fit the observations. This degeneracy prevents a self-consistent determination of the gas energetics and, therefore, of the efficiency in transporting the AGN energy outwards. We analyse a joint XMM-Newton and NuSTAR observation of the bright, highly-variable AGN NGC 4051. The high flux allows to perform time-resolved spectroscopy and, thus, to study the evolution of its three main ionised absorbers. Since the timescale of the gas ionisation variability depends on its number density, constraining it allows to break the density-distance degeneracy. We employ the Time-Evolving PhotoIonisation Device (TEPID) to model the temporal evolution of the outflows. We split the observation in 37 time-resolved spectra, each few kiloseconds long (total duration 160 ksec), and we fit them jointly with the time-resolved ionised spectra. We fully constrain $n_e=10^7 cm^{-3}$ and $r=10^4$ gravitational radii for the absorber with the highest opacity and intermediate ionisation. This distance is the same of the optical and UV Broad Line Region and of the soft X-ray emission lines. The fastest and most ionised absorber is at $r<600 r_G$, cospatial with the broad component of the Fe K$\alpha$ line. The slowest and least ionised absorber is at $r \geq 3.8 \cdot 10^5 r_G$, the same distance of the cold torus and the narrow Fe K$\alpha$. The total energy outflow rate is below $10^{-4} L_{bol}$, ruling out a meaningful mechanical impact on the host galaxy.

Figures

Figures reproduced from arXiv: 2607.20621 by the authors.

Figure 1
Figure 1. Top: NGC 4051 lightcurve in the 2.10 keV range with XMM￾Newton (blue) and in the 3-79 keV range with NuSTAR (green). The time is from the start of the NuSTAR observation. Bottom: XMM￾Newton 0.5-10 keV lightcurve (blue) and the average flux of the time bins (black). 3. The Time-Evolving PhotoIonisation Device (TEPID) model 3.1. Code updates TEPID has been significantly updated since the first version pre￾sented in Lu… view at source ↗
Figure 4
Figure 4. Gas temperature as a function of time for log(U0) = 0 and the NGC 4051 lightcurve from [PITH_FULL_IMAGE:figures/full_fig_p004_4.png] view at source ↗
Figure 3
Figure 3. Limit NH up to which TEPID and Cloudy predicted ionic columns are in agreement (i.e. within 50% one another), as a function of log(U). at t > 0 is still derived according to U0 and then varied follow￾ing to the lightcurve. However, the radiation at t = 0 does not correspond to that for U0, but to fU · U0. Setting fU < 1(> 1) mimics, to a first order, an initial under-(over-) ionisation [PITH_FULL_IMAGE:figures/full… view at source ↗
Figures from the paper (8 more)
Figure 5
Figure 5. Figure 5: TEPID input SED at three different times: black line is at t=0, while red and green lines are at the time of the highest and lowest XMM-Newton observed fluxes, respectively [PITH_FULL_IMAGE:figures/full_fig_p005_5.png]
Figure 7
Figure 7. Figure 7: Top: black body temperature as a function of the observing time (left y-axis). Red dots report the 0.5-2 keV luminosity in each temporal bin (right y-axis). Bottom: normbb as a function of normpl. (top right panel). More interestingly, the normalisation is con￾stant in…
Figure 8
Figure 8. Figure 8: Trend of Γ and normalisation of the reflection component. Left column: Γ against 2-10 keV flux (top) and normalisation (bottom). Right column: Γ (top) and normalisation (bottom) as a function of the observing time. icance. We obtain upper and lower limits on the number…
Figure 9
Figure 9. Figure 9: Contour plot of the ionisation Log(U0) versus the number density log(ne/cm−3 ) (x- and y-axis, respectively) for the LIP, HIP and HVIP modelled with TEPID. The levels correspond to 1,2,3 σ significance. 0 5 10 15 20 25 30 35 Time bin 0.010 0.015 0.020 0.025 0.030 0.035…
Figure 10
Figure 10. Figure 10: Opacity lightcurve for the HIP. The shaded green area corre￾sopnds to the ±1σ best-fit confidence interval for log(ne). Dashed and dotted lines are for log(ne/cm−3 ) = 5, 10, respectively. Blue points and errorbars, instead, are opacity derived by fitting the spectra …
Figure 11
Figure 11. Figure 11: Same as [PITH_FULL_IMAGE:figures/full_fig_p008_11.png]
Figure 12
Figure 12. Figure 12: Fe X, Fe XI, O VII ion abundances (top to bottom) for the LIP component, as a function of the observing time. Solid line is the tabulated solution closest to the best-fit values, while dark- and light￾shaded regions are the ±1σ interval for fU and logU0 respectively. …
Figure 13
Figure 13. Figure 13: Cartoon showing the relative radial locations (not to scale) of all the absorption and emission components in the innermost accretion disc region (see Sect. 5.1.) a similar distance through the relative line intensities of the O VII emission complex in a 2009 low-stat…

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Works this paper leans on

63 extracted references · 5 canonical work pages

  1. [1]

    A., & Kallman, T

    Bautista, M. A., & Kallman, T. R. 2001, ApJS, 134, 139, doi:10.1086/320363

    doi:10.1086/320363 2001

  2. [2]

    2026, A&A, 710, A274, doi:10.1051/0004-6361/202659493

    Bianchi, S., Vander Meulen, B., Bertola, E., et al. 2026, A&A, 710, A274, doi:10.1051/0004-6361/202659493

    work page doi:10.1051/0004-6361/202659493 2026

  3. [3]

    A., Altun, Z., & Badnell, N

    Bleda, E. A., Altun, Z., & Badnell, N. R. 2022, A&A, 668, A72, doi:10.1051/ 0004-6361/202244043

    2022

  4. [4]

    W., Wilkins, D

    Brenneman, L. W., Wilkins, D. R., Ogorzałek, A., et al. 2025, ApJ, 995, 200, doi:10.3847/1538-4357/ae1225

    doi:10.3847/1538-4357/ae1225 2025

  5. [5]

    R., Davis, J

    Canizares, C. R., Davis, J. E., Dewey, D., et al. 2005, PASP, 117, 1144, doi:10. 1086/432898

    2005

  6. [6]

    L., Rodríguez-Ardila, A., et al

    Coffey, D., Longinotti, A. L., Rodríguez-Ardila, A., et al. 2014, MNRAS, 443, 1788, doi:10.1093/mnras/stu1294

    work page doi:10.1093/mnras/stu1294 2014

  7. [7]

    J., Brandt, W

    Collinge, M. J., Brandt, W. N., Kaspi, S., et al. 2001, ApJ, 557, 2, doi:10.1086/ 321635 de Vaucouleurs, G., de Vaucouleurs, A., Corwin, Jr., H. G., et al. 1991, S&T, 82, 621

    2001

  8. [8]

    A., Kallman, T

    Ding, Y ., Garcıa, J. A., Kallman, T. R., et al. 2024, ApJ, 974, 280, doi:10.3847/ 1538-4357/ad76a1

    2024

Show all 63 references
  1. [9]

    2000, ApJ, 545, 63 Faucher-Giguère, C.-A., & Quataert, E

    Elvis, M. 2000, ApJ, 545, 63 Faucher-Giguère, C.-A., & Quataert, E. 2012, MNRAS, 425, 605, doi:10.1111/ j.1365-2966.2012.21512.x

    2000

  2. [10]

    M., Grier, C

    Fausnaugh, M. M., Grier, C. J., Bentz, M. C., Denney, K. D., & De Rosa, G. e. a. 2017, ApJ, 840, 97, doi:10.3847/1538-4357/aa6d52

    2017 doi

  3. [11]

    2024, A&A, 686, A36, doi:10.1051/0004-6361/202345849

    Fiore, F., Gaspari, M., Luminari, A., Tozzi, P., & de Arcangelis, L. 2024, A&A, 686, A36, doi:10.1051/0004-6361/202345849

    2024 doi

  4. [12]

    2017, A&A, 601, A143, doi:10.1051/ 0004-6361/201629478

    Fiore, F., Feruglio, C., Shankar, F., et al. 2017, A&A, 601, A143, doi:10.1051/ 0004-6361/201629478

    2017

  5. [13]

    2001, in Society of Photo-Optical In- strumentation Engineers (SPIE) Conference Series, V ol

    Freeman, P., Doe, S., & Siemiginowska, A. 2001, in Society of Photo-Optical In- strumentation Engineers (SPIE) Conference Series, V ol. 4477, Astronomical Data Analysis, ed. J.-L. Starck & F. D. Murtagh, 76–87, doi:10.1117/12. 447161 García, J., Elhoussieny, E. E., Bautista, M...

    2001 doi

  6. [14]

    2019, A&A, 630, A94, doi:10.1051/0004-6361/ 201833810

    Giustini, M., & Proga, D. 2019, A&A, 630, A94, doi:10.1051/0004-6361/ 201833810

    2019 doi

  7. [15]

    1991, ApJ, 380, L51

    Haardt, F., & Maraschi, L. 1991, ApJ, 380, L51

    1991

  8. [16]

    A., Craig, W

    Harrison, F. A., Craig, W. W., Christensen, F. E., et al. 2013, ApJ, 770, 103, doi:10.1088/0004-637X/770/2/103 Article number, page 11 of 14 A&A proofs:manuscript no. main HI4PI Collaboration, Ben Bekhti, N., Flöer, L., et al. 2016, A&A, 594, A116, doi:10.1051/0004-6361/201629178

    2013 doi

  9. [18]

    2001, A&A, 365, L1, doi:10.1051/ 0004-6361:20000036

    Jansen, F., Lumb, D., Altieri, B., et al. 2001, A&A, 365, L1, doi:10.1051/ 0004-6361:20000036

    2001

  10. [19]

    2025, ApJ, 994, L13, doi:10

    Kammoun, E., Kawamuro, T., Murakami, K., et al. 2025, ApJ, 994, L13, doi:10. 3847/2041-8213/ae18c2

    2025

  11. [20]

    N., George, I

    Kaspi, S., Brandt, W. N., George, I. M., et al. 2002, ApJ, 574, 643, doi:10. 1086/341113

    2002

  12. [21]

    2015, ARA&A, 53, 115, doi:10.1146/ annurev-astro-082214-122316

    King, A., & Pounds, K. 2015, ARA&A, 53, 115, doi:10.1146/ annurev-astro-082214-122316

    2015

  13. [22]

    2024, ApJ, 972, 32, doi:10.3847/ 1538-4357/ad5b5a

    Kosec, P., Rogantini, D., Kara, E., et al. 2024, ApJ, 972, 32, doi:10.3847/ 1538-4357/ad5b5a

    2024

  14. [23]

    2026, ApJ, 1004, 104, doi:10.3847/ 1538-4357/ae680a

    Kosec, P., Brenneman, L., Kara, E., et al. 2026, ApJ, 1004, 104, doi:10.3847/ 1538-4357/ae680a

    2026

  15. [24]

    B., Crenshaw, D

    Kraemer, S. B., Crenshaw, D. M., Dunn, J. P., et al. 2012, ApJ, 751, 84, doi:10. 1088/0004-637X/751/2/84

    2012

  16. [25]

    H., & Kriss, G

    Krolik, J. H., & Kriss, G. A. 1995, ApJ, 447, 512, doi:10.1086/175896

    1995 doi

  17. [26]

    S., et al

    Krongold, Y ., Nicastro, F., Brickhouse, N. S., et al. 2003, ApJ, 597, 832, doi:10. 1086/378639

    2003

  18. [27]

    2007, ApJ, 659, 1022, doi:10.1086/ 512476

    Krongold, Y ., Nicastro, F., Elvis, M., et al. 2007, ApJ, 659, 1022, doi:10.1086/ 512476

    2007

  19. [28]

    L., Santos-Lleó, M., et al

    Krongold, Y ., Longinotti, A. L., Santos-Lleó, M., et al. 2021, ApJ, 917, 39, doi:10.3847/1538-4357/ac0977

    2021 doi

  20. [29]

    2021, A&A, 645, A118, doi:10

    Laurenti, M., Luminari, A., Tombesi, F., et al. 2021, A&A, 645, A118, doi:10. 1051/0004-6361/202039409

    2021

  21. [30]

    P., Reeves, J

    Lobban, A. P., Reeves, J. N., Miller, L., et al. 2011, MNRAS, 414, 1965, doi:10. 1111/j.1365-2966.2011.18513.x

    2011

  22. [31]

    L., Krongold, Y ., Guainazzi, M., et al

    Longinotti, A. L., Krongold, Y ., Guainazzi, M., et al. 2015, ApJ, 813, L39, doi:10.1088/2041-8205/813/2/L39

    2015 doi

  23. [32]

    2021, A&A, 646, A111, doi:10

    Luminari, A., Nicastro, F., Elvis, M., et al. 2021, A&A, 646, A111, doi:10. 1051/0004-6361/202039396

    2021

  24. [33]

    Luminari, A., Nicastro, F., Krongold, Y ., Piro, L., & Thakur, A. L. 2023, A&A, 679, A141, doi:10.1051/0004-6361/202245600

    2023 doi

  25. [34]

    A., Brusa, M., Lanzuisi, G., et al

    Matzeu, G. A., Brusa, M., Lanzuisi, G., et al. 2023, A&A, 670, A182, doi:10. 1051/0004-6361/202245036

    2023

  26. [35]

    1998, A&AS, 133, 403, doi:10.1051/aas:1998330

    Mazzotta, P., Mazzitelli, G., Colafrancesco, S., & Vittorio, N. 1998, A&AS, 133, 403, doi:10.1051/aas:1998330

    1998 doi

  27. [36]

    S., Eckart, M

    Mehdipour, M., Kaastra, J. S., Eckart, M. E., et al. 2025, A&A, 699, A228, doi:10.1051/0004-6361/202555623

    2025 doi

  28. [37]

    2026, A&A, 710, A118, doi:10

    Middei, R., Piconcelli, E., Nardini, E., et al. 2026, A&A, 710, A118, doi:10. 1051/0004-6361/202659321

    2026

  29. [38]

    M., Xiang, X., Mehdipour, M., et al

    Miller, J. M., Xiang, X., Mehdipour, M., et al. 2026, arXiv e-prints, arXiv:2604.16148, doi:10.48550/arXiv.2604.16148

    2026 doi arXiv

  30. [39]

    C., & Elvis, M

    Nicastro, F., Fiore, F., Perola, G. C., & Elvis, M. 1999, ApJ, 512, 184, doi:10. 1086/306736

    1999

  31. [40]

    2025, ApJ, 993, L53, doi:10.3847/ 2041-8213/ae14e8

    Noda, H., Yamada, S., Ogawa, S., et al. 2025, ApJ, 993, L53, doi:10.3847/ 2041-8213/ae14e8

    2025

  32. [41]

    M., Mason, K

    Ogle, P. M., Mason, K. O., Page, M. J., et al. 2004, ApJ, 606, 151, doi:10.1086/ 382744

    2004

  33. [42]

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

    2006

  34. [43]

    M., & Behar, E

    Peretz, U., Miller, J. M., & Behar, E. 2019, ApJ, 879, 102, doi:10.3847/ 1538-4357/ab23ef

    2019

  35. [44]

    2002, ApJ, 580, 261, doi:10.1086/343081

    Perna, R., & Lazzati, D. 2002, ApJ, 580, 261, doi:10.1086/343081

    2002 doi

  36. [45]

    M., McHardy, I

    Peterson, B. M., McHardy, I. M., Wilkes, B. J., et al. 2000, ApJ, 542, 161, doi:10.1086/309518

    2000 doi

  37. [47]

    N., Ogawa, S., Turner, T

    Reeves, J. N., Ogawa, S., Turner, T. J., et al. 2026, ApJ, 1001, 137, doi:10. 3847/1538-4357/ae5527

    2026

  38. [48]

    2022, ApJ, 940, 122, doi:10

    Rogantini, D., Mehdipour, M., Kaastra, J., et al. 2022, ApJ, 940, 122, doi:10. 3847/1538-4357/ac9c01

    2022

  39. [49]

    B., & Lightman, A

    Rybicki, G. B., & Lightman, A. P. 1979, Radiative processes in astrophysics

    1979

  40. [50]

    R., Bautista, M

    Sadaula, D. R., Bautista, M. A., García, J. A., & Kallman, T. R. 2023, ApJ, 946, 93, doi:10.3847/1538-4357/acbd40

    2023 doi

  41. [51]

    R., Kallman, T

    Sadaula, D. R., Kallman, T. R., & Laha, S. 2025, ApJ, 992, 182, doi:10.3847/ 1538-4357/ae032f

    2025

  42. [52]

    2017, A&A, 600, A101, doi:10.1051/ 0004-6361/201629885

    Serafinelli, R., Vagnetti, F., & Middei, R. 2017, A&A, 600, A101, doi:10.1051/ 0004-6361/201629885

    2017

  43. [53]

    2024, A&A, 690, A145, doi:10

    Serafinelli, R., De Rosa, A., Tortosa, A., et al. 2024, A&A, 690, A145, doi:10. 1051/0004-6361/202450777

    2024

  44. [54]

    2025, ApJ, 995, 6, doi:10.3847/ 1538-4357/ae1614

    Serafinelli, R., Nicastro, F., Luminari, A., et al. 2025, ApJ, 995, 6, doi:10.3847/ 1538-4357/ae1614

    2025

  45. [55]

    I., & Sunyaev, R

    Shakura, N. I., & Sunyaev, R. A. 1973, A&A, 24, 337

    1973

  46. [56]

    W., Yaqoob, T., & Wang, J

    Shu, X. W., Yaqoob, T., & Wang, J. X. 2010, ApJS, 187, 581, doi:10.1088/ 0067-0049/187/2/581

    2010

  47. [57]

    A., & Papadakis, I

    Sobolewska, M. A., & Papadakis, I. E. 2009, MNRAS, 399, 1597, doi:10. 1111/j.1365-2966.2009.15382.x

    2009

  48. [58]

    C., Fenov ˇcík, M., Kaastra, J

    Steenbrugge, K. C., Fenov ˇcík, M., Kaastra, J. S., Costantini, E., & Verbunt, F. 2009, A&A, 496, 107, doi:10.1051/0004-6361/200810416 Strüder, L., Briel, U., Dennerl, K., et al. 2001, A&A, 365, L18

    2009 doi

  49. [59]

    2020, in Society of Photo-Optical In- strumentation Engineers (SPIE) Conference Series, V ol

    Tashiro, M., Maejima, H., Toda, K., et al. 2020, in Society of Photo-Optical In- strumentation Engineers (SPIE) Conference Series, V ol. 11444, Space Tele- scopes and Instrumentation 2020: Ultraviolet to Gamma Ray, ed. J.-W. A. den

    2020

  50. [60]

    Nikzad, & K

    Herder, S. Nikzad, & K. Nakazawa, 1144422, doi:10.1117/12.2565812

    doi

  51. [61]

    L., Piro, L., Luminari, A., et al

    Thakur, A. L., Piro, L., Luminari, A., et al. 2026, Nature Astronomy, doi:10. 1038/s41550-026-02786-w

    2026

  52. [62]

    Tortosa, A., Bianchi, S., Marinucci, A., Matt, G., & Petrucci, P. O. 2018, A&A, 614, A37, doi:10.1051/0004-6361/201732382

    2018 doi

  53. [63]

    D., McHardy, I

    Uttley, P., Taylor, R. D., McHardy, I. M., et al. 2004, MNRAS, 347, 1345, doi:10.1111/j.1365-2966.2004.07321.x

    2004

  54. [64]

    M., Veilleux, S., McKernan, B., & Kallman, T

    Winter, L. M., Veilleux, S., McKernan, B., & Kallman, T. R. 2012, ApJ, 745, 107, doi:10.1088/0004-637X/745/2/107 Xrism Collaboration, Audard, M., Awaki, H., et al. 2024, ApJ, 973, L25, doi:10. 3847/2041-8213/ad7397 —. 2025, Nature, 641, 1132, doi:10.1038/s41586-025-08968-2

    2012 doi

  55. [65]

    2024, ApJS, 274, 8, doi:10

    Yamada, S., Kawamuro, T., Mizumoto, M., et al. 2024, ApJS, 274, 8, doi:10. 3847/1538-4365/ad5961 Article number, page 12 of 14 A. Luminari et al.: Time-evolving Diagnostic of the Ionized Absorbers in NGC 4051. II. Appendix A: Fit of the time-averaged spectra We fit the time-av...

    2024

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