Elliptical (E) and ellicular (ES) galaxies in the M_bh-M_*,sph diagram, and a merger-driven explanation for the origin of ES galaxies, anti-truncated stellar discs in lenticular galaxies, and the Sersicification of E galaxy light profiles

Alister W. Graham

REVIEW 4 major objections 6 minor 19 references

Elliptical (E) and ellicular (ES) galaxies in the M_bh-M_*,sph diagram, and a merger-driven explanation for the origin of ES galaxies, anti-truncated stellar discs in lenticular galaxies, and the Sersicification of E galaxy light profiles

T0 review · 4 major / 6 minor · reviewed 2026-08-10 · deepseek-v4-flash

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Pith's one-line read This paper argues that elliptical and ellicular galaxies occupy separate black-hole scaling tracks, and that the black-hole–spheroid-mass diagram records a merger-driven galaxy speciation sequence.

desk verdict New decompositions and a plausible speciation story, but the central ES/e versus E separation is asserted, not demonstrated. read the letter →

arxiv 2501.09953 v1 pith:TYEFPDCB submitted 2025-01-17 astro-ph.GA

Alister W. Graham This is my paper · ORCID

classification astro-ph.GA

keywords galaxyevolutionsupermassiveblackholesellipticalgalaxieslenticularellicularmergersstellardiscsSersiclightprofiles

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

This paper argues that elliptical (E) and ellicular (ES) galaxies—those with an intermediate-scale stellar disc—occupy distinct regions of the black-hole-mass versus spheroid-stellar-mass diagram, so the diagram encodes a merger-driven speciation sequence. The cleaned sample of non-brightest-cluster ellipticals defines a steep, roughly quadratic relation, while ES,e galaxies bridge the gap between merger-built lenticular galaxies and ellipticals. The paper also shows that anti-truncated (up-bending) disc profiles in some lenticular galaxies can be understood as a steep inner disc coexisting with a shallower outer disc, which lowers bulge-to-total ratios and implies that past bulge masses were overestimated. It concludes that merger-driven disc heating and blending produce the high-Sérsic-index light profiles of elliptical galaxies.

What carries the argument

The load-bearing object is the M_bh–M_*,sph diagram together with multi-component light-profile decompositions of 3.6-micron Spitzer images. The key mechanism is the double-disc decomposition: for NGC 3379, NGC 4649, NGC 3091, and NGC 4697, adding a steep intermediate-scale exponential disc alongside a shallower large-scale disc—equivalently one anti-truncated disc—drops the fitted Sérsic index of the spheroid from above 2 to below 2 and lowers the bulge-to-total ratio to roughly 1/4. The anti-truncated profile is thereby explained as the coexistence of two discs, the expected fossil of a merger of two disc galaxies. The evolutionary argument is carried by merger-driven disc heating, erosion, and blending: the inner, denser disc outlives the fragile outer disc, producing ES galaxies with embedded discs, and further erosion yields the apparently discless, high-Sérsic-index profiles of ellipticals.

What would settle it

Deep 3.6-micron imaging or integral-field spectroscopy of NGC 3379 and NGC 4649 extending beyond roughly 200 arcseconds, with independent sky-background measurement: if the outer exponential component shows no rotation, no disc-like flattening, and disappears when the background is remeasured, the double-disc interpretation and the accompanying bulge-mass reductions would fail.

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Extended reading notes

Core claim

On the paper's own terms, the central discovery is that ES,e galaxies are not drawn from the same population as non-BCG E galaxies: the discless ellipticals have systematically higher spheroid masses for their black-hole masses, interpreted as a record of more extensive disc-destroying dry mergers. After four galaxies are reclassified as lenticular because previously missed discs are detected, the non-BCG E sample shrinks to 13 galaxies and the ES,e sample to 10, and the ellipticals then define log(M_bh/M_sun) = (2.03 ± 0.19)[log(M_*,sph/M_sun) − 11.60] + (9.39 ± 0.07). Because a dry merger roughly doubles stellar mass while adding much less black-hole mass, successive mergers move galaxies rightward and downward along a steep, super-quadratic track, producing the observed offsets among S0, ES,e, E, and brightest-cluster galaxies. A corollary is that the steep relations for merger-built systems, rather than near-linear relations from mixed samples, are the appropriate benchmarks for predicting supermassive-black-hole merger rates and gravitational-wave backgrounds.

Load-bearing premise

The load-bearing premise is that the double-disc and anti-truncated profiles assigned to NGC 3379, NGC 4649, NGC 3091, and NGC 4697 are real stellar structures rather than artifacts of sky-background oversubtraction or neighboring-galaxy contamination; if the outer upward bend in these profiles is a background artifact, the lowered bulge masses and the S0 reclassifications collapse.

Editorial extensions

If this is right

Gravitational-wave predictions should use the steep, merger-built M_bh–M_*,sph and M_bh–M_*,gal relations; near-linear relations from mixed samples would misestimate black-hole merger rates from galaxy mass functions.
Bulge masses and bulge-to-total ratios derived from a single Sérsic bulge plus one exponential disc are overestimated for lenticular galaxies with anti-truncated discs; refitting lowers B/T ratios from about 0.5 to about 0.25.
ES,e galaxies should be treated as a separate morphological class in black-hole scaling-relation work, because pooling them with E galaxies biases the slope and zero-point of the relation.
The status of NGC 3379 as an archetypal R^{1/4} galaxy needs revision: its light profile is better represented by a low-Sérsic-index spheroid plus two stellar discs.
Mergers, not AGN feedback, are presented as the primary agent establishing the black-hole scaling relations for these massive galaxy types, with AGN feedback reduced to a maintenance role.

Reading between the lines

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

If the speciation sequence holds, ES galaxies should appear as a relatively short-lived transitional population; counting ES galaxies relative to S0 and E galaxies in deep surveys could directly test the implied merger rates.
The double-disc origin of anti-truncated profiles is testable in simulations: equal-mass disc mergers should produce two exponential discs with the right inner-to-outer scalelength ratio, turning into an anti-truncated light profile after projection.
The same decomposition logic suggests that the Sérsic index of a spheroid is not a reliable fossil of bulge origin, since merger-built bulges can have n < 2 once discs are properly included.
Gravitational-wave background searches that weight merger-built galaxies using steep M_bh–M_* relations may predict higher low-frequency background amplitudes than those using near-linear relations from mixed galaxy samples.

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Editorial analysis

A structured set of objections, weighed in public.

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

Desk Editor's Note

read the letter

Know this: the paper brings new data—remodelled Spitzer profiles for several early-type galaxies, four reclassifications from E to S0, one from E to ES, and a revised Mbh-M*,sph relation for non-BCG ellipticals with slope 2.03. The central claim that ES,e and E galaxies occupy different locations in the Mbh-M*,sph diagram is not supported by a statistical test. The author says no reliable relation can be derived for the ten ES,e galaxies, and the visual separation in Fig. 3 mostly reflects the high-mass tail of the E sample and the low-mass ES,e points. That is a real soft spot.

What the paper does well is the careful decomposition work. The double-disc and anti-truncated disc models for NGC 3379 and NGC 4649 are plausible, and the author explicitly flags the sky-subtraction uncertainty at r~260'' rather than hiding it. The interpretation of anti-truncated discs as a merger product of two discs is a useful, testable idea. The revised E galaxy relation is a reasonable update, though it rests on twelve points after excluding NGC 6251.

The load-bearing problem is that the four reclassified S0 galaxies have spheroid masses lowered by up to half a dex because of the newly added discs. If the outer bends are sky-subtraction artifacts, those masses rise and the S0 classification weakens. The author acknowledges this but still uses the resulting masses to define the dotted-line S0 relation against which the ES/e and E offsets are interpreted. That is a circular step, even if not intentionally so. Also, the ES,e sample includes NGC 1275, a BCG. It is the most massive point and including it in the "non-BCG" ES/e comparison muddies the sample. A simple two-sample test on the spheroid mass distributions, and a sensitivity analysis to the sky background, would address both concerns.

The heavy self-citation is justified because this is the author's own long-running framework; the relevant prior papers are the ones being extended. The speculation about gravitational wave backgrounds is fine as a pointer.

This paper is for people working on black hole scaling relations, galaxy morphology, and the assembly history of early-type galaxies. It deserves a serious referee, because the new decompositions will be used even if the speciation sequence is wrong. My recommendation: send it to review, but with the clear expectation that the author add a statistical test for the ES/e vs E separation and a quantitative sensitivity analysis for the sky-subtraction-dependent decompositions. Without those, the central claim remains an interesting hypothesis.

Referee Report

4 major / 6 minor

Summary. The paper revisits the M_bh–M_*,sph diagram for elliptical (E) and ellicular (ES) galaxies, presenting revised photometric decompositions for several nearby early-type galaxies (notably NGC 3379, NGC 4649, NGC 4697, and NGC 3091) and claiming that the ES,e and non-BCG E galaxies occupy distinct regimes, with E galaxies having systematically higher spheroid masses. The author interprets this separation as evidence for a merger-driven speciation sequence (massive S0 → ES → E) and interprets the offset of brightest cluster galaxies (BCGs) from non-BCG E galaxies as the result of an additional dry major merger. The paper also proposes that anti-truncated stellar discs in S0 galaxies arise from the coexistence of a steep intermediate-scale disc and a shallower large-scale disc, and that merger-driven disc heating and blending produce the high-Sérsic-index ('Sérsicified') light profiles of E galaxies. New scaling relations are reported in Table 2 and Eq. (1), including a slope of 2.03±0.19 for the non-BCG E galaxy M_bh–M_*,sph relation.

Significance. If the claimed ES,e/E population separation is robust, the paper would strengthen an evolving merger-driven galaxy speciation picture and would provide a useful empirical benchmark: the steep (slope ≈ 2) M_bh–M_* relations for merger-built systems would be the appropriate references for predictions of massive black hole merger rates and the gravitational wave background. The paper is valuable for its detailed photometric case studies, especially the NGC 3379 and NGC 4649 decompositions, and for its explicit caveats about sky-background uncertainties at large radii. However, the central statistical claim of a population separation is not yet demonstrated with the small samples used, and the reclassification of four galaxies as S0 systems is sensitive to exactly the sky-subtraction issues the author flags. The interpretive framework is coherent and builds on a systematic program of galaxy decomposition, but the quantitative basis for the key population offset currently rests on small-number fits and visual inspection.

major comments (4)

[Section 3, Fig. 3] The central claim that 'The ES,e galaxies are clearly not drawn from the same population as the non-BCG E galaxies' (Section 3) is not backed by a statistical test. With only 10 ES,e galaxies and 13 E galaxies (12 used in the E fit), the visual separation in Fig. 3 could be driven by the high-mass E tail (NGC 1600, NGC 1407, IC 1459, NGC 4374, NGC 3923, NGC 4261, NGC 7619) and the low-mass ES,e galaxies. The paper itself states that 'removing one or two ES,e data points is enough to sway the distribution and, therefore, no reliable relation is derived for this sample.' A formal two-population test (e.g., a permutation test on spheroid masses at fixed M_bh, or a likelihood-ratio comparison of a single versus two-population model) is needed to support the claimed separation.
[Section 2.3.1 and Appendix A1.1] The reclassification of NGC 3379 and NGC 4649 as S0 galaxies, with spheroid masses roughly 0.5 dex lower than they would have as single-Sérsic E galaxies, depends on the reality of the outer light-profile bend at r ≈ 250 arcsec. The author explicitly flags that this bend 'could conceivably be due to an over-subtraction of the actual "sky background"' (Section 2.3.1), and a similar caveat is given for NGC 4649 in Appendix A1.1. Because these reclassified galaxies are placed in the S0 sample that defines the dotted-line relation in Fig. 3, and because their spheroid masses directly affect the relative positions of the E and ES,e populations, this systematic uncertainty is load-bearing. The paper should provide a quantitative robustness test, for example by refitting the profiles with the data beyond the bend excluded or with a sky level perturbed by the measured uncertainty, and showing how the spheroid masses and the population separation change.
[Section 3, Eq. (1)] The non-BCG E galaxy relation is fit to 12 galaxies after excluding NGC 6251 'to provide a more robust result,' but no robust outlier criterion is given. With only 12-13 points, the exclusion of a single object can materially change the slope and intercept. The paper should present the fit with NGC 6251 included, along with a robust regression (e.g., an outlier-tolerant likelihood or least trimmed squares), to demonstrate that the reported slope (2.03±0.19) and intercept (9.39±0.07) are not artifacts of this one exclusion.
[Section 3, Fig. 3, and Section 4.4] The interpretation that the BCG offset corresponds to a mass-doubling dry major merger is asserted from visual inspection of 10 BCGs and 12 E galaxies. The arrows in Fig. 3 are illustrative and not a quantitative model. The claim that BCGs are 'not simply the high-mass end of the non-BCG E galaxy mass-scaling relation' requires a formal comparison, such as fitting a single relation to the combined sample and testing whether a two-population model is preferred, and a merger model that tracks both M_bh and M_*,sph changes. Without such a test, the mass-doubling interpretation is a speculative overlay on the same data that define the relations, and it risks circularity because the BCG offset is measured relative to the E-galaxy relation that the merger scenario is supposed to explain.

minor comments (6)

[Section 4.1] The phrase 'anti-truncrated disc model' appears to be a typo for 'anti-truncated disc model.'
[Section 2.3.1] The sentence 'The upward bend in the light profile of NGC 3379, starting at r≈110 arcsec, is not due to an insufficient subtraction of the "sky background"' is ambiguous: the concern at larger radii is over-subtraction, not insufficient subtraction; please clarify the direction of the potential sky error.
[Table 1] The column header '(10− 1 S0 + 1 former ES =) 10 ES,e galaxies' is confusing; the arithmetic would be clearer presented in a footnote or in the text, with the column simply stating '10 ES,e galaxies.'
[Fig. 3 caption] The arrows are not defined in the caption; please state what vector length and direction represent in terms of mass-doubling and M_bh growth, and note that the arrows are illustrative rather than a quantitative model prediction.
[Abstract and Section 4.4] The abstract describes '(super-)quadratic M_bh-M_* relations,' but the non-BCG E galaxy slope is 2.03±0.19, which is consistent with exactly quadratic; the super-quadratic description is only supported for the BCG (2.40±0.40) and S0/Es,b (2.63±0.78) samples. Please qualify the wording accordingly.
[Section 4.2.2] The term 'Sérsicification' is used before it is introduced; consider defining it at first use as the process by which composite bulge/disc light profiles are smoothly described by a single high-n Sérsic model.

Circularity Check

1 steps flagged · score 3.0 of 10

No load-bearing circularity in the central Mbh-M*,sph claims; one definitional re-labeling of anti-truncated discs as a two-disc 'explanation'.

renaming known result [Section 2.3.1 (NGC 3379), Figure 2; also abstract]
"The double disc structure in the upper panel of Figure 2 suggests that a single anti-truncated disc model (Pohlen et al. 2002; Erwin et al. 2005) may be applicable, and this is shown in the lower panel of Fig. 2."

An anti-truncated (Type III) disc is, by definition, a broken exponential whose outer segment is shallower than the inner segment. The 'double disc structure' fitted in the upper panel is exactly a steep intermediate-scale exponential plus a shallow large-scale exponential, so the lower-panel anti-truncated fit is a reparameterization of the same two-component model rather than an independent confirmation. The paper's follow-up statement that 'the anti-truncated nature of (some) S0 galaxy discs may, therefore, be due to the merging of galaxy discs' imports the merger origin from external simulations and literature; it is not derived from the profile decomposition.

full rationale

The central empirical claims of the paper are not circular in the sense defined by the review rules. The E and ES,e samples are separated by morphological disc detections and kinematic evidence, not by the fitted Mbh-M*,sph relation; indeed, the paper explicitly reports no reliable regression for the ES,e sample ('no reliable relation is derived for this sample'). The ~0.5 dex offset in spheroid mass between the E and ES,e medians cannot be produced merely by subtracting the quoted 5-20% disc light from the ES,e spheroids, since that correction is at most 0.1 dex. The E-galaxy Mbh-M*,sph relation is fit to the E sample and then used as a reference to examine the independent BCG sample; the BCG 'mass-doubling' expectation is an arithmetic consequence of the steep fitted slope and a simple equal-mass-merger assumption, not a parameter fitted to the BCGs. Thus the BCG offset is an out-of-sample, falsifiable comparison. Self-citations (Graham & Sahu 2023a,b; Graham 2023c) supply published photometric decompositions, black hole masses, and earlier scaling relations; those are reproducible inputs with stated methods, not assumptions equivalent to the present conclusions. The main weaknesses are statistical (small samples, no two-sample test, sensitivity of the outer-disc decompositions to possible sky-subtraction errors), which are robustness and evidentiary concerns rather than circularity. The one definitional re-labeling identified above concerns the anti-truncated-disc narrative and is not load-bearing for the central Mbh-M*,sph population-separation claim.

Assumptions & free parameters 7 free parameters · 6 assumptions · 0 invented entities

No new physical entities are introduced; 'ellicular' and 'Sersicification' are classification and process terms, not entities. The main free parameters are the fitted scaling relation slopes and intercepts, plus the photometric decomposition parameters for the remodelled galaxies.

free parameters (7)

E galaxy Mbh-M*,sph slope = 2.03 +/- 0.19
Fitted to 12 non-BCG E galaxies after excluding NGC 6251; the relation is Eq. 1.
E galaxy Mbh-M*,sph intercept = 9.39 +/- 0.07
Intercept at log(M*,sph/Msun)=11.60 in Eq. 1.
BCG Mbh-M*,sph slope = 2.40 +/- 0.40
Fitted to 10 BCGs, Table 2.
BCG Mbh-M*,sph intercept = 9.49 +/- 0.13
Table 2.
S0/Es,b Mbh-M*,sph slope = 2.63 +/- 0.78
Fitted to 18 dust-rich S0/ES,b galaxies, Table 2.
S0/Es,b Mbh-M*,sph intercept = 8.42 +/- 0.18
Table 2.
Photometric decomposition parameters = varied per galaxy, see figures
Sersic n, effective radius, disc scalelengths, etc. for the remodelled galaxies are fitted to the Spitzer 3.6 micron light profiles and determine the quoted spheroid and galaxy stellar masses.

assumptions (6)

domain assumption Sersic function and exponential disc models adequately describe galaxy light profiles
Used for all galaxy decompositions; if the functional forms are wrong, derived component masses change.
domain assumption The 3.6 micron stellar mass-to-light ratio is given by the color-dependent relation of Graham & Sahu (2023a) with a diet Salpeter IMF
Used to convert all magnitudes to stellar masses; a different IMF shifts all masses uniformly.
domain assumption Black hole masses from Graham & Sahu (2023a) are accurate
The Mbh values are taken as direct measurements from the literature; errors in Mbh would directly affect all scaling relations.
ad hoc to paper The dust-rich S0 galaxies are major-merger remnants
The classification is imported from a literature review in Graham (2023b) and is not independently established here.
ad hoc to paper A dry major merger of two E galaxies doubles the spheroid stellar mass while approximately doubling or preserving Mbh, yielding the BCG offset
Used to interpret the rightward offset of BCGs in Fig. 3; not derived in this paper.
ad hoc to paper The outer light profile bends at large radii are not due to sky-subtraction errors
The author acknowledges a possible over-subtraction in NGC 3379 but proceeds with the double-disc model.

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Cite this review

Pith. "Pith review of Elliptical (E) and ellicular (ES) galaxies in the M_bh-M_*,sph diagram, and a merger-driven explanation for the origin of ES galaxies, anti-truncated stellar discs in lenticular galaxies, and the Sersicification of E galaxy light profiles." pith.science (2026). https://pith.science/paper/TYEFPDCB

@misc{pith2026250109953,
  author       = {Pith},
  title        = {Pith review of: Elliptical (E) and ellicular (ES) galaxies in the M_bh-M_*,sph diagram, and a merger-driven explanation for the origin of ES galaxies, anti-truncated stellar discs in lenticular galaxies, and the Sersicification of E galaxy light profiles},
  year         = {2026},
  howpublished = {\url{https://pith.science/paper/TYEFPDCB}},
  note         = {Machine review of arXiv:2501.09953}
}

abstract

In a recent series of papers, supermassive black holes were used to discern pathways in galaxy evolution. By considering the black holes' coupling with their host galaxy's bulge/spheroid, the progression of mass within each component has shed light on the chronological sequence of galaxy speciation. Offsets between the galaxy-morphology-dependent M_bh-M_*,sph scaling relations trace a pattern of 'punctuated equilibrium' arising from merger-driven transitions between galaxy types, such as from spirals to dust-rich lenticulars and further to `ellicular' and elliptical galaxies. This study delves deeper into the distinction between the ellicular galaxies - characterised by their intermediate-scale discs - and elliptical galaxies. Along the way, it is shown how some anti-truncated large-scale discs in lenticular galaxies can arise from the coexistence of a steep intermediate-scale disc and a relatively shallow large-scale disc. This observation undermines application of the popular exponential-disc plus S\'ersic-bulge model for lenticular galaxies and suggests some past bulge mass measurements have been overestimated. Furthermore, it is discussed how merger-driven disc-heating and blending likely leads to the spheroidalisation of discs and the conglomeration of multiple discs leads to the (high n) Sersicification of light profiles. The ellicular and elliptical galaxy distribution in the $M_{\rm bh}$-$M_{\rm\star,sph}$ diagram is explored relative to major-merger-built lenticular galaxies and brightest cluster galaxies. The (super-)quadratic $M_{\rm bh}$-$M_{\rm\star}$ relations, presented herein, for merger-built systems should aid studies of massive black hole collisions and the gravitational wave background. Finally, connections to dwarf compact elliptical and ultra-compact dwarf galaxies, with their 100-1000 times higher $M_{\rm bh}/M_{\rm\star,sph}$ ratios, are presented.

Figures

Figures reproduced from arXiv: 2501.09953 by the authors.

**Figure 1.** Left: Spitzer/IRAC1 3.6 µm image of NGC 3379, courtesy of S4G (pipeline 1 image: Muñoz-Mateos et al. 2015). The scale bar is 100′′ = 5.3 kpc long. North is up, and east is left. Middle panel: The galaxy light of NGC 3379 and the ‘sky-background’ have been independently determined and subtracted. Right panel: Sérsic spheroid (red curve, Re,maj = 20′′ .9, µe = 18.90 mag arcsec−2 , and nmaj = 2.74) and exponential disc… view at source ↗

**Figure 2.** Preferred decompositions for NGC 3379. Top panel: Sérsic spheroid (red curve: Re,maj = 6 ′′ .4, µe = 17.10 mag arcsec−2 , and nmaj = 1.44) plus intermediate-scale disc (straight blue line: µ0 = 18.23 mag arcsec−2 , h = 21′′ .5 = 1.14 kpc) and weakly-truncated (at r = 261′′) largescale disc (bent blue line: µ0 = 20.97 mag arcsec−2 , hinner = 74′′ = 3.9 kpc, houter = 50′′ = 2.65 kpc). Bottom panel: Sérsic spheroid (r… view at source ↗

**Figure 3.** Mbh-M⋆,sph and Mbh-M⋆,gal diagrams and relations for BCG (dashed line), non-BCG E galaxies (solid line), and non-BCG major-merger-built S0 galaxies (dotted line). The arrows show a mass doubling from an equal-mass dry-major-merger, taking galaxies rightward of the steeper than linear Mbh-M⋆,gal relation shown here. (The dust-rich S0 galaxy NGC 3489 happens to reside on the Mbh-M⋆,gal relation defined by the non-BCG … view at source ↗

Figures from the paper (2 more)

**Figure 4.** Figure 4: Progressive speciation of common galaxy types, revealing the Sérsicification of galaxy light profiles as Sérsic n ≈ 1 discs give way to higher-n profiles that decline slowly at large radii. The schematic also helps to visualise/explain the construction of the Re,gal-n …

**Figure 5.** Figure 5: Adaption of figure 6 from Graham & Sahu (2023b), incorporating figure 2 from Graham (2020) for the nuclear star clusters (NSCs) and ultracompact dwarf (UCD) galaxies plus an updated version of figure 1 from Graham (2023c) based on the remodelled galaxies presented here…

Discussion (0). Continue with ORCID to comment.

Reference graph

Works this paper leans on

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[2016]

is rotating sufficiently fast, it may be considered an S0 galaxy

results in an overestimation of the light at large radii. is rotating sufficiently fast, it may be considered an S0 galaxy. As with NGC 4278 and NGC 4494 (previously mentioned but not in the current sample), Bellstedt et al. (2017a) report an upturn in the spin parameter for N...

2017
[3091]

plus a Sérsic bulge (red curve:µe = 18.75 mag arcsec−2, nmaj = 2.17, and Re,maj = 7′′.0)

Upper panel: An intermediate-scale disc (µ0 = 19.57 mag arcsec−2, h = 17′′.3 = 4.8 kpc) and large-scale disc (µ0 = 21.56 mag arcsec−2, h = 57′′ = 15.7 kpc). plus a Sérsic bulge (red curve:µe = 18.75 mag arcsec−2, nmaj = 2.17, and Re,maj = 7′′.0). Lower panel: Sérsic spheroid (...

1989
[3607]

A2.2 NGC 4291 Jedrzejewski & Schechter (1989) report V/σ = 76/273 = 0.28 for NGC 4291, which makes it a ‘fast (inner) rotator’, although the rotation falls from 100 km s−1 at 3′′ to 40 km s−1 at 12′′, before peaking again at∼15′′ and then falling back down to∼50 km s−1 by 20′′...

1989
[4291]

The scale bar is 50 ′′ = 9.45 kpc long

Image courtesy of SHA. The scale bar is 50 ′′ = 9.45 kpc long. The light profile is decomposed into a Sérsic spheroid (dashed red curve: nmaj = 4.40, Re,maj = 39′′.7, andµe = 21.87 mag arcsec−2), a broad Gaussian ring aligned with the major axis and having a peak ring-to-spher...

2023
[4647]

The disc is also evident in the kinematic map from Krajnovi´c et al

Right: Major axis light profile decomposed into a Sérsic spheroid (red curve: Re,maj = 22′′.5,µe = 18.61 mag arcsec−2, and nmaj = 2.04) and exponential disc (straight blue line: µ0 = 19.73 mag arcsec−2, hdisc,maj = 68′′ = 5.3 kpc). The disc is also evident in the kinematic map...

2011
[4697]

Spitzer/IRAC1 3.6µm image courtesy of S4G (pipeline 1 image: Muñoz-Mateos et al. 2015). The scale bar is 150′′ = 8.1 kpc long. Right panel: The open circles were excluded from the fit. For reference: nsph,maj = 2.4, Re,sph,maj = 24′′,µe,sph = 18.98 mag arcsec−2, µ0,disc = 20.2...

2015
[5077]

Nonetheless, the light profiles are still better modelled by including an inner and faint intermediate-scale component

Although it has a similar light profile to NGC 4291, little to no trace of a double disc structure is apparent in its light profile. Nonetheless, the light profiles are still better modelled by including an inner and faint intermediate-scale component. A3 A couple of elliptica...

1991

Pith tools

Reviewed August 10, 2026 · model on record in the stance chip above.

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Agazie G., et al., 2024, ApJ, 966, 105 Alabi A. B., et al., 2015, MNRAS, 452, 2208 Alcock C., et al., 2000, ApJ, 542, 281 20 https://doi.org/10.26132/NED1 21 https://irsa.ipac.caltech.edu/applications/Spitzer/SHA MNRAS 000, 1–22 (2024) 14 Graham Alcock C., et al., 2001, ApJ, 550, L169 Almoznino E., Loinger F., Brosch N., 1993, MNRAS, 265, 641 Amaro-Seoane...

doi:10.26132/ned1 2024

[2] [5]

2006; Dullo & Graham

Finally, as with the discussion around NGC 3379, the need for a large partially depleted core in NGC 4649 (Ferrarese et al. 2006; Dullo & Graham

work page 2006

[3] [6]

This is one of the reasons why vast numbers of automated single- Sérsic fits to massive galaxies overestimate their luminosities. Of course, while the two-component fit gives improved/stable galaxy magnitudes, the component parameters can still be quite erroneous, as repeatedly illustrated here in Section A1.1. MNRAS 000, 1–22 (2024) 18 Graham 150" Figure...

work page 2024

[4] [8]

This ‘hot’ outer disc model gives a bulge (aka spheroid) magnitude of 10.39 mag and a total galaxy magnitude of 8.74 mag, as mentioned in Section A1.2

Lower panel: Major axis light profile fit with a Sérsic spheroid (red curve, Re,maj = 9′′.5 and nmaj = 2.12) and an anti-truncated disc (bent blue line, µ0 = 18.27, Rbend,maj = 92′′, hinner,maj = 31′′ = 1.67 kpc, and houter,maj = 65′′ = 3.51 kpc). This ‘hot’ outer disc model gives a bulge (aka spheroid) magnitude of 10.39 mag and a total galaxy magnitude ...

work page 2014

[5] [14]

A9 has been included to help visualise how a heated thick outer ‘disc’ can produce a dynamically-hot spheroid-dominated (Fig

The fit shown in Fig. A9 has been included to help visualise how a heated thick outer ‘disc’ can produce a dynamically-hot spheroid-dominated (Fig. A8). The decomposition in Fig. A9 only applies if NGC 3607 has an over- looked face-on large-scale disc. Richings et al. (2011) report a de- pleted core with a break radius Rb = 0′′.22 in NGC

work page 2011

[6] [18]

MNRAS 000, 1–22 (2024) 22 Graham 50" Figure A11

and is, there- fore, not expected to be surrounded by a halo of stars stripped from other galaxy cluster members. MNRAS 000, 1–22 (2024) 22 Graham 50" Figure A11. Similar to Fig. 1, but for NGC 5077, which retains its E galaxy designation, although it arguably may be considered an ES galaxy, like NGC

work page 2024

[7] [1809]

H., 1966, ApJ, 146, 28 Lima Neto G

Läsker R., Ferrarese L., van de Ven G., 2014, ApJ, 780, 69 Laurikainen E., Salo H., Buta R., 2005, MNRAS, 362, 1319 Li Y ., et al., 2020, ApJ, 895, 102 Liller M. H., 1966, ApJ, 146, 28 Lima Neto G. B., Gerbal D., Márquez I., 1999, MNRAS, 309, 481 Liu B., Bromm V ., 2022, ApJ, 937, L30 Loubser S. I., Lagos P., Babul A., O’Sullivan E., Jung S. L., Olivares ...

arXiv 2024

[8] [1977]

is remodelled in Fig. A12. This Seyfert 2 galaxy has a one-sided jet — reported at radio wavelengths by Waggett et al. (1977) and Perley et al. (1984) — that can be seen in the residual image (Fig. A12, middle panel). The dominant spheroid’s Sérsic index equals 4.0, and its apparent magnitude equals 11.29 mag. The galaxy’s total magnitude is M3.6,gal = 11...

work page 1977