REVIEW
A Fundamental Relation Between Supermassive Black Holes and Their Host Galaxies
Astrophysics · Submitted 4 Jun 2000 · 2 references
Pith's verdict: The M–σ paper: the slope of 4.8 is the durable part, and the 'negligible intrinsic scatter' claim is the part that does not survive scrutiny.
T0 · AI review
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Referee report
The paper
The paper claims
Black hole mass tracks the random motions of bulge stars, not the bulge's brightness, and the fit is tight enough that one low-resolution spectrum predicts the mass.
The reading
What carries the argument
The machinery is a bivariate linear regression that allows for intrinsic scatter as well as errors in both variables (Akritas & Bershady 1996), applied with black hole mass as the dependent variable and either bulge absolute magnitude $B^0_T$ or aperture-corrected central velocity dispersion $sigma_c$ as the independent one. The aperture correction, which brings every dispersion to the equivalent of a radius $r_e/8$ following Jorgensen, Franx & Kjaergaard (1995), is small, rarely above five percent, and the authors check that it changes neither slope nor intercept. The comparison between the two independent variables is what makes the argument: the same sample, the same fitting method, two different galaxy properties, and only one of them produces a residual scatter that the error bars can account for.
Extended reading notes
Core claim
The central claim is Eq. (1): $log M_*{BH} = 4.80(pm 0.54),log sigma_c - 2.9(pm 1.3)$, with $M_*{BH}$ in solar masses and $sigma_c$ in km/s, fitted to the twelve galaxies of Sample A. The reduced chi-squared of that fit is 0.8, i.e. the spread about the line is consistent with the stated measurement errors alone, whereas the same galaxies scatter far more widely about the $M_*{BH}$–luminosity plane. The authors argue the correlation is not an artifact of the black hole perturbing the stars whose motions are being measured: substituting the rms velocity $v_*{rms}$ at a quarter of the effective radius, well outside the black hole's gravitational reach, leaves the slope unchanged. They also report that the Magorrian et al. (1998) masses, derived from ground-based stellar kinematics, sit systematically above the Sample A line, some by two orders of magnitude, and they read that offset as evidence that those mass estimates are upper limits rather than detections.
Load-bearing premise
The twelve galaxies were chosen because the observations resolved the black hole's sphere of influence, and that radius grows with black hole mass, so the sample is not independent of the quantity being predicted.
Editorial extensions
If this is right
- Black hole masses can be estimated for large galaxy samples from existing stellar velocity dispersion measurements, without spatially resolved kinematics, opening population studies that were previously limited to a dozen objects.
- If the slope is near five, then combining the Faber–Jackson relation $L propto sigma^4$ with the early-type mass-to-light scaling $M propto L^{5/4}$ gives $M_*{BH}$ roughly proportional to bulge mass, i.e. a roughly universal baryon-to-black-hole conversion fraction.
- The same $sigma^5$ scaling follows from models in which quasar outflows halt accretion once the outflow energy matches the bulge binding energy, so the observed slope is a natural test of that feedback picture.
- Correlation studies built on the Magorrian et al. (1998) masses, such as Merriefield, Forbes & Terlevich (2000), should be re-examined, since those masses appear to be biased high for distant galaxies.
- The relation should not be extrapolated to black holes below roughly $10^5$ solar masses, where the formation channel may differ.
Reading between the lines
- The sample was assembled from galaxies in which the black hole's sphere of influence was spatially resolved, and that radius scales as $G M_*{BH}/sigma^2$; a sample selected that way preferentially keeps large black holes at a given dispersion, so an independent test using galaxies selected purely by distance or by observability, with no reference to black hole mass, would be the cleanest check on
- Because the relation predicts mass from a quantity measurable in a single low-resolution spectrum, it converts every nearby early-type galaxy with a published dispersion into a black hole mass estimate, which is the practical reason the result propagated so widely.
- The systematic upward offset of the ground-based stellar-kinematic masses is itself a claim about measurement, not about black holes: if it is right, the same bias should appear in any other mass estimator whose resolution element is larger than the sphere of influence, and that is checkable galaxy by galaxy.
Original abstract
The masses of supermassive black holes correlate almost perfectly with the velocity dispersions of their host bulges, M(BH) ~ sigma^alpha, where alpha =4.8 +/- 0.5$. The relation is much tighter than the relation between M(BH) and bulge luminosity, with a scatter no larger than expected on the basis of measurement error alone. Black hole masses estimated by Magorrian et al. (1998) lie systematically above the M(BH)-sigma relation defined by more accurate mass estimates, some by as much as two orders of magnitude. The tightness of the M(BH)-sigma relation implies a strong link between black hole formation and the properties of the stellar bulge.
The compiled record
The paper's own sentences, arranged, kept beside the review and separate from it. Each label is drawn from a closed vocabulary; the number beside it is the probability the classifier gave that label. Numbers in the tables are the authors', checked by code. No sentence in this record was written by a model.
The abstract, sentence by sentence
The masses of supermassive black holes correlate almost perfectly with the velocity dispersions of their host bulges, M(BH) ~ sigma^alpha, where alpha =4.8 +/- 0.5$. The relation is much tighter than the relation between M(BH) and bulge luminosity, with a scatter no larger than expected on the basis of measurement error alone. Black hole masses estimated by Magorrian et al. (1998) lie systematically above the M(BH)-sigma relation defined by more accurate mass estimates, some by as much as two orders of magnitude. The tightness of the M(BH)-sigma relation implies a strong link between black hole formation and the properties of the stellar bulge.
background contribution method result interpretation main claim
| # | sentence | role | the authors' own work | states the main conclusion | strength |
|---|---|---|---|---|---|
| s0 | The masses of supermassive black holes correlate almost perfectly with the velocity dispersions of their host bulges, M(BH) ~ sigma^alpha, where alpha =4.8 +/- 0.5$. | result 1.00 | 0.67 | 0.68 | asserted 1.00 |
| s1 | The relation is much tighter than the relation between M(BH) and bulge luminosity, with a scatter no larger than expected on the basis of measurement error alone. | result 1.00 | 0.75 | 0.16 | asserted 1.00 |
| s2 | Black hole masses estimated by Magorrian et al. (1998) lie systematically above the M(BH)-sigma relation defined by more accurate mass estimates, some by as much as two orders of magnitude. | result 0.91 | 0.39 | 0.07 | asserted 1.00 |
| s3 | The tightness of the M(BH)-sigma relation implies a strong link between black hole formation and the properties of the stellar bulge. | interpretation 1.00 | 0.54 | 0.59 | asserted 0.76 |
What was examined, and what was not
- arXiv listing abstract v2
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References
How later papers used it
681 later papers cite it
4 later papers by other authors are listed below: 3 used its method or tool and 1 used its data or values.
Uses its method or tool 3 of 15 papers with this label
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Estimated the black hole mass using this paper's scaling law with the observed stellar velocity dispersion of 70±10 km/s.
A (likely) X-ray jet from NGC6217 observed by XMM-Newton (2017) · 0.98 · paraphrased: the licence does not allow quoting
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Used the empirical correlation between black hole mass and host galaxy stellar velocity dispersion from this paper to estimate the black hole mass for the AGN in 3C 223.
The Complex X-ray Obscuration Environment in the Radio Loud Type 2 Quasar 3C 223 (2023) · 0.88 · paraphrased: the licence does not allow quoting
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The SMBH mass is $3.3×10^7 M_⊙$, $2.3×10^7 M_⊙$ and $3.9×10^7 M_⊙$ based on the empirical relations $M_BH-σ_*$ in [ref] , [ref] and [ref] respectively.
A Composite Broad-Line Region in SDSS J1609+4902: a Double-Peaked Disk component and a Gaussian Component (2025) · Spectrum Decomposition · 0.87
Uses its data or values 1 of 9 papers with this label
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Fit the normalization A to the observational data of this paper for each alpha varied between 3.5 and 5.
AGN feedback in dwarf galaxies? (2017) · 0.81 · paraphrased: the licence does not allow quoting
How the literature uses it
107 arXiv papers cite this in 119 sentences
Papers citing it · 80 sentences without a confident label
Uses its method or tool 3 papers
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For many of these, masses were derived from the relation between $M_BH$ and the bulge stellar velocity dispersion $σ_⋆$ [ref] .
Mapping the nuclear environments of extreme coronal line emitting galaxies · Black hole masses · 0.87
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For the remaining quasars, the tight correlation between the mass $M$ and the stellar velocity dispersion $σ$ is exploited to estimate their masses [ref] .
Excavating black hole continuum spectrum: Possible signatures of scalar hairs and of higher dimensions · Numerical analysis: What does observations tell us? · 0.82
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For thirteen quasars the $M-σ$ relation is also used to constrain their masses [ref] .
In quest of axionic hairs in quasars · Results Based on Numerical Analysis · 0.99
Uses its data or values 1 paper
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For a sub-sample of thirteen quasars [ref] , the masses are also reported by $M-σ$ method [ref] .
Imprints of the Janis-Newman-Winicour spacetime on observations related to shadow and accretion · Observational sample · 0.88
Compares with it 1 paper
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Interestingly, all our sources except NGC 4945 lie on the M-$σ$ relation predicted by different models [ref] .
Unveiling the Fast Acceleration of AGN-Driven Winds at Kiloparsec Scales · Theoretical predictions on AGN outflow acceleration · 0.84
Cites it as support 1 paper
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Furthermore, the [ref] models also provides a deep solution for the existence of the black hole mass – galaxy scaling relationships (e.g., [ref] ).
A Review of Galaxy Quenching -- Part II: Theoretical Solutions and Direct Observational Tests · II) The quasar-mode AGN feedback paradigm · 0.96
Cites it as background 32 papers
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The correlation between a supermassive black hole's mass, $M_bh$, and the stellar velocity dispersion, $σ$, of its host spheroid [ref] is often regarded as the most fundamental of the black hole scaling relations.
Galaxy morphology dependent (black hole mass)-(velocity dispersion) relations: implications for gravitational wave forecasts and cosmological simulations · Introduction · 1.00
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While the direct black hole masses can only be derived in a small portion of nearby galaxies, some empirical relations are proposed, e.g. the relation between the supermassive black hole mass and stellar velocity dispersion ($M_BH - σ_⋆$) [ref] .
Even central galaxies feel their environment: cosmic siphoning of cool gas accretion · The black hole masses · 0.84
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Empirically, this co-evolutionary nature is manifested in well-established local scaling relations between BH masses and key host galaxy properties, including stellar bulge mass ($M_∙- M_⋆$), stellar velocity dispersion ($M_∙- σ_⋆$), dynamical mass ($M_∙- M_dyn$) and luminosity ($M_∙- L$) [ref] .
Small hosts, big appetites: unveiling rapid and early low-mass black hole growth in cosmological zoom-in simulations of dwarf galaxies · Introduction · 0.94
Discussion
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