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The black hole-galaxy correlations of the 12 micron local AGN sample: a NuSTAR perspective

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M. Gliozzi, L. Spinoglio, J. A. Fernandez-Ontiveros, M. A. Malkan, J. K. Williams, M. Young. A. D. Oxley, S. Satyapal

Astrophysics of Galaxies · Submitted 21 Oct 2026 · 296 references

Pith's verdict: A credible, well-validated test of M-sigma for local AGN on one homogeneous mass scale; the offset and scatter are the solid findings, the slope claim is softer than the prose, and the uncalibrated mix of sigma sources deserves a robustness check.

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arXiv ID2610.30285 (version 1)
Pith IDZWLFVMFG, Pith's permanent record of this paper and its review
CitationJ. A. Fernandez-Ontiveros, J. K. Williams, L. Spinoglio, M. A. Malkan, M. Gliozzi, M. Young. A. D. Oxley, S. Satyapal. "The black hole-galaxy correlations of the 12 micron local AGN sample: a NuSTAR perspective." arXiv:2610.30285 (2026). https://pith.science/paper/ZWLFVMFG
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The paper

The paper claims

Local AGN follow a black-hole–velocity-dispersion relation different from inactive galaxies, with lighter black holes at a given dispersion, so inactive-galaxy mass estimates for AGN are often overestimated.

The reading

The paper sets out to test whether the black hole mass–stellar velocity dispersion ($M_{\rm BH}$–$\sigma_\star$) relation calibrated on inactive galaxies can be used to estimate black hole masses in active galactic nuclei (AGN), including obscured ones where no broad-line measurement is possible. Using the 12 micron AGN sample — a bolometric-flux-limited, mid-infrared-selected set of 59 local Seyfert 1, Seyfert 2, and hidden broad-line region galaxies — the authors derive masses from the X-ray scaling method applied to NuSTAR spectra, a technique they validate against dynamical masses for 41 sources. They find the AGN $M_{\rm BH}$–$\sigma_\star$ relation is markedly different from the inactive-galaxy relation: at a given velocity dispersion black holes are systematically lighter, and the intrinsic scatter (0.45 $\pm$ 0.10 dex) is large enough that the relation has limited predictive power for individual masses. If the claim holds, black hole masses for AGN inferred from the standard inactive-galaxy relation are often overestimated, which would bias Eddington ratios and population statistics built on them. The paper also finds the AGN $M_{\rm BH}$–$M_\star$ relation agrees with the relation for local type 1 AGN, and that hidden broad-line region galaxies accrete closer to Seyfert 1 levels than to Seyfert 2 levels.

What carries the argument

The load-bearing object is the X-ray scaling method: black hole mass is obtained by scaling the accretion luminosity of the AGN — measured from the normalization of a bulk-motion Comptonization model fitted to NuSTAR spectra — against dynamically calibrated stellar-mass black holes in X-ray binaries, matched by accretion state through the photon index $\Gamma$. The ratio $L_{\rm AGN}/L_{\rm ref}$ equals $M_{\rm BH,AGN}/M_{\rm BH,ref}$ because black hole systems in the same accretion state share the same Eddington-scaled accretion rate and radiative efficiency. Because the method requires only hard X-ray spectra, it puts Seyfert 1, Seyfert 2, and HBLR galaxies on a common mass scale without needing a visible broad-line region or any host-galaxy scaling relation. The paper validates it against 41 sources with maser, gas-dynamical, reverberation-mapping, and single-epoch masses, finding consistency with the one-to-one relation. The other key element is the 12 micron AGN sample itself, a mid-infrared flux-limited selection insensitive to obscuration, whose bolometric luminosities come from ten-band SED integration.

Extended reading notes

Core claim

The paper's central claim is that the $M_{\rm BH}$–$\sigma_\star$ relation of the 12 micron AGN sample is $\log(M_{\rm BH}/M_\odot) = (7.50 \pm 0.17) + (2.66 \pm 0.77)\log(\sigma_\star/200\,{\rm km\,s^{-1}})$ with intrinsic scatter $\epsilon = 0.45 \pm 0.10$ dex, markedly different from the Kormendy & Ho (2013) relation for inactive galaxies with classical bulges: AGN at a given $\sigma_\star$ have systematically lower black hole masses, and the scatter is roughly double. The authors argue this is not a selection artifact, showing that the 59-AGN subsample is statistically indistinguishable from the 104-object parent sample in bolometric luminosity, stellar mass, and specific star formation rate. No difference is seen among Seyfert 1, Seyfert 2, and HBLR galaxies in the $M_{\rm BH}$–$\sigma_\star$ plane, whereas host morphology plays a role: lenticular galaxies cluster near the inactive relation while spirals lie below it, and the AGN fit is broadly consistent with the star-forming ridgeline of Chen et al. (2020). The conclusion is that the inactive-galaxy relation should not be applied to AGN for individual mass estimates — such masses are likely overestimated — and that the AGN relation itself has fairly limited predictive power.

Load-bearing premise

The load-bearing premise is that the stellar velocity dispersions — about half from targeted observations and half from the Hyperleda catalog — are on a common, bulge-dominated systematics scale; if the catalog dispersions measure something systematically different, part of the offset and the 0.45 dex scatter relative to inactive galaxies could be an artifact of the dispersion measurements rather than an intrinsic property of AGN hosts.

Editorial extensions

If this is right

  • Black hole masses for obscured AGN that are directly inferred from the inactive-galaxy $M_{\rm BH}$–$\sigma_\star$ relation, the standard practice for type 2 AGN, are likely overestimated; the paper cites prior work finding overpredictions of 0.6–0.9 dex relative to dynamical and infrared-based masses.
  • Because the reverberation-mapping virial factor is calibrated by forcing RM AGN onto the inactive-galaxy relation, the RM and single-epoch mass scales inherit any offset in that relation and may need recalibration.
  • Population-level quantities built from inactive-galaxy-derived masses, such as Eddington-ratio distributions and black hole mass functions for obscured AGN, would carry a systematic offset that could distort comparisons among AGN classes.
  • The $M_{\rm BH}$–$M_\star$ relation remains usable for AGN ensemble studies: the IR-selected sample agrees with the type 1 AGN relation of Reines & Volonteri (2015), even though its 0.39 dex scatter still precludes reliable individual masses.
  • The AGN sample's position near the star-forming ridgeline of Chen et al. (2020) supports the picture that these hosts are still in the black-hole-growth phase, moving from the blue cloud toward the red sequence.

Reading between the lines

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

  • A robustness test the paper does not run: recompute the $M_{\rm BH}$–$\sigma_\star$ fit using only the half of the sample with high-resolution dispersion measurements; if the offset and scatter persist, the result does not depend on the Hyperleda velocity dispersions.
  • If local AGN hosts are genuinely in an earlier black-hole-growth phase, star-forming hosts at high redshift should deviate from local inactive-galaxy relations in the same direction — a prediction to test, since the authors caution that their local sample is not a direct analog of high-redshift AGN.
  • The marginal difference in Eddington ratio between hidden broad-line region galaxies and Seyfert 2s, if confirmed with larger samples, would support the idea that the broad-line region forms only above an accretion-rate threshold and that HBLRs are the obscured counterparts of Seyfert 1s.
  • Targeted dynamical masses for a handful of the lowest-mass outliers such as NGC 5194 would test whether the X-ray scaling method's low-mass end, rather than host-galaxy physics, contributes part of the offset.
Original abstract

The M-sigma correlation of inactive galaxies plays a crucial role in estimating the black hole mass (MBH) in active galactic nuclei (AGN): 1) it is used to calibrate the reverberation mapping (RM) method; 2) the RM is the basis of the single epoch method, the most-used technique to determine MBH of broad-line AGN; and 3) in narrow-line AGN, MBH is often directly inferred from the M-sigma correlation. The main goal of this work is to test whether the M-sigma relation calibrated from inactive galaxies can be reliably applied to a local AGN population spanning Seyfert 1, Seyfert 2, and hidden broad-line region galaxies (HBLRs), and whether the resulting AGN relation has sufficient predictive power to be used as an indirect MBH estimator. To investigate this hypothesis, we used the 12 micron AGN sample, a local representative and largely unbiased sample. Since a substantial fraction of this sample has good-quality NuSTAR data, we estimated their MBH with the X-ray scaling method, which works for any AGN accreting at moderate or high level. We find that the M-sigma correlation of the 12 micron AGN sample is different from the one obtained with inactive galaxies and has a substantial scatter. Therefore, its predictive power for MBH estimates is fairly limited. We also find that the MBH-Mgal correlation based on the 12 micron AGN sample is consistent with the analogous correlation obtained from a large sample of nearby type 1 AGN and inconsistent with that of inactive galaxies. Finally, we find suggestive evidence that Seyfert 1 and HBLRs have similar and systematically higher Eddington ratios than Seyfert 2 galaxies.

The compiled record

The paper's own sentences, arranged, kept beside the review and separate from it. Each label is drawn from a closed vocabulary; the number beside it is the probability the classifier gave that label. Numbers in the tables are the authors', checked by code. No sentence in this record was written by a model.

Compiled by classifier-1.13.0 via TypeSafe API, question bank abstract-p1-20260923, 2026-10-23: 1 request, 6,553 input tokens.

What the abstract itself states, as probabilities: claims first 0.03 · states limitation 0.92 · human participants 0.01 · controlled comparison 0.85 · randomized assignment 0.01 · states quantitative result 0.13 · compares with prior results 0.97 · mentions code or data availability 0.02.

The abstract, sentence by sentence

arXiv listing abstract v1. Results and the main claim are underlined; .

The M-sigma correlation of inactive galaxies plays a crucial role in estimating the black hole mass (MBH) in active galactic nuclei (AGN): 1) it is used to calibrate the reverberation mapping (RM) method; 2) the RM is the basis of the single epoch method, the most-used technique to determine MBH of broad-line AGN; and 3) in narrow-line AGN, MBH is often directly inferred from the M-sigma correlation. The main goal of this work is to test whether the M-sigma relation calibrated from inactive galaxies can be reliably applied to a local AGN population spanning Seyfert 1, Seyfert 2, and hidden broad-line region galaxies (HBLRs), and whether the resulting AGN relation has sufficient predictive power to be used as an indirect MBH estimator. To investigate this hypothesis, we used the 12 micron AGN sample, a local representative and largely unbiased sample. Since a substantial fraction of this sample has good-quality NuSTAR data, we estimated their MBH with the X-ray scaling method, which works for any AGN accreting at moderate or high level. We find that the M-sigma correlation of the 12 micron AGN sample is different from the one obtained with inactive galaxies and has a substantial scatter. Therefore, its predictive power for MBH estimates is fairly limited. We also find that the MBH-Mgal correlation based on the 12 micron AGN sample is consistent with the analogous correlation obtained from a large sample of nearby type 1 AGN and inconsistent with that of inactive galaxies. Finally, we find suggestive evidence that Seyfert 1 and HBLRs have similar and systematically higher Eddington ratios than Seyfert 2 galaxies.

background contribution method result interpretation main claim

What the classifier reports for each sentence. The number is the probability it gave the label.
#sentencerolethe authors' own workstates the main conclusionstrength
s0 The M-sigma correlation of inactive galaxies plays a crucial role in estimating the black hole mass (MBH) in active galactic nuclei (AGN): 1) it is used to calibrate the reverberation mapping (RM) method; 2) the RM is the basis of the single epoch method, the most-used technique to determine MBH of broad-line AGN; and 3) in narrow-line AGN, MBH is often directly inferred from the M-sigma correlation. background 1.00 0.04 0.02 asserted 1.00
s1 The main goal of this work is to test whether the M-sigma relation calibrated from inactive galaxies can be reliably applied to a local AGN population spanning Seyfert 1, Seyfert 2, and hidden broad-line region galaxies (HBLRs), and whether the resulting AGN relation has sufficient predictive power to be used as an indirect MBH estimator. contribution 0.87 0.16 0.05 unclear 0.45
s2 To investigate this hypothesis, we used the 12 micron AGN sample, a local representative and largely unbiased sample. method 0.90 0.60 0.02 asserted 0.98
s3 Since a substantial fraction of this sample has good-quality NuSTAR data, we estimated their MBH with the X-ray scaling method, which works for any AGN accreting at moderate or high level. method 0.99 0.93 0.02 asserted 1.00
s4 We find that the M-sigma correlation of the 12 micron AGN sample is different from the one obtained with inactive galaxies and has a substantial scatter. result 1.00 0.97 0.47 asserted 1.00
s5 Therefore, its predictive power for MBH estimates is fairly limited. interpretation 0.86 0.86 0.39 asserted 0.97
s6 We also find that the MBH-Mgal correlation based on the 12 micron AGN sample is consistent with the analogous correlation obtained from a large sample of nearby type 1 AGN and inconsistent with that of inactive galaxies. result 1.00 0.95 0.13 asserted 0.64
s7 Finally, we find suggestive evidence that Seyfert 1 and HBLRs have similar and systematically higher Eddington ratios than Seyfert 2 galaxies. result 1.00 0.95 0.05 hedged possibility 0.93

What kind of paper the classifier reports this is: empirical study 1.00 · evidence from analysis of existing data 0.87.

What was examined, and what was not

sources read
  • arXiv listing abstract v1
not examined
  • full text
  • figures and tables
  • references and citing sentences
  • relations to other papers
levels run
  • P abstract
not run
  • S sections
  • T body sentences
  • C citations
  • R cross-paper relations

Every quoted sentence on this record is the authors'. Every label is from Pith's closed vocabulary, with the probability shown beside it. Every number in the measurements table is the authors', checked by code. Record as JSON

Figures
Figure 1. shows the MBH values obtained with the X-ray scaling method (MBH,X) plotted versus the corresponding values derived with various dynamical methods (MBH,dyn) with a color-coded scheme based on λEdd. A visual inspection of this figure indicates the overall good agreement between values derived with the X-ray scal￾ing method and the dynamical ones, as confirmed by a Spear￾man rank coefficient of ρ = 0.66 (PS = 2.3 × 10−6 ) and an orthogonal distance regression (ODR; Spinoglio et al. 2022) fit: log(MBH,dyn/M⊙) = (0.85±0.72)+(0.90±0.10)×log(MBH,X/M⊙). NGC 1194 and NGC 7582, which are not…
Figure 2. log(λEdd) plotted versus log(MBH) for the Seyfert 1 (blue circles), Seyfert 2 (red squares), and HBLR galaxies (green triangles). For each colored symbol, the horizontal error bars represent the uncertainties on log(MBH) and the vertical error bars of 0.2 dex are the uncertainties on log(λEdd) used in our analysis. The corresponding larger black symbols represent the averages for the three AGN subclasses along with their respective uncertainties σ/ √ n, where n is the number of objects in each AGN subclass. The same figure suggests a possible difference between the log(λEdd)…
Figure 4. The histogram of the bolometric luminosity log(Lbol) of the two samples. In black the complete 12 µm AGN sample from which the LINERs have been subtracted, containing 104 AGN and in red the sam￾ple used in this work, with good NuSTAR spectral data, containing 59 AGN. A similar result is found if we compare the two samples in terms of the stellar masses of the host galaxies of the AGN, as can be seen in the histogram in
Figure 5. The histogram of the stellar mass log(M∗/M⊙) of the two sam￾ples. In black the complete 12 µm AGN sample from which the LINERs have been subtracted, containing 104 AGN and in red the sample used in this work, with good NuSTAR spectral data, containing 59 AGN. The MBH–σ⋆ correlation, found for the 12 µm sample (
Figure 6. The histogram of the specific star formation rate log(sSFR/Gyr−1 ) of the two samples. In black the complete 12 µm AGN sample from which the LINERs have been subtracted, containing 86 AGN and in red the sample used in this work, with good NuSTAR spectral data, containing 58 AGN. 8:5 9:0 9:5 10:0 10:5 11:0 11:5 log(M?=M¯) 5 6 7 8 9 lo g ( M B H = M ¯ ) Seyfert1 Seyfert2 HBLR this work Reines&Volonteri15
Figure 7. Black hole mass in logarithmic form log(MBH) plotted versus the logarithm of the stellar mass log(M⋆) for the Seyfert 1 (blue circles), Seyfert 2 (red squares), and HBLR galaxies (green triangles). The black continuous line represents the linear best fit and the magenta dashed line indicates the best fit found by Reines & Volonteri (2015) using a large sample of type 1 AGN. The shaded region represents the 0.39 dex intrinsic scatter around our best-fit linear model. The MBH–M⋆ correlation shown in
Figure 8. log(MBH) plotted versus log(σ⋆) showing the morphological classification of the host galaxies: blue diamonds represent spiral galax￾ies, magenta squares are lenticular galaxies, and red circles are ellipti￾cal galaxies. The black continuous line represents the linear best fit, the green short-dashed line indicates the best fit found by Kormendy & Ho (2013) using inactive galaxies with classical bulges, the red long-dashed line indicates the quenched ridgeline and the blue dashed line the star￾forming ridgeline from Chen et al. (2020). The shaded regions account for the errors on the…

Showing 7 of the paper's 9 figures. See all figures in the PDF ↗ Figures reproduced from arXiv:2610.30285 by the authors.

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