arxiv: 2603.28856 · v1 · submitted 2026-03-30 · 🌌 astro-ph.GA · astro-ph.IM

Recognition: 1 theorem link

· Lean Theorem

MUSE-DARK-II: 3D morpho-kinematic modelling of lensed galaxies. Tully-Fisher relation of z sim 1 star-forming galaxies

Alexandre Jeanneau , Johan Richard , Nicolas F. Bouch\'e , Davor Krajnovi\'c , Bianca-Iulia Ciocan , Jonathan Freundlich , Beno\^it Epinat , Thierry Contini

Authors on Pith no claims yet

Pith reviewed 2026-05-14 21:43 UTC · model grok-4.3

classification 🌌 astro-ph.GA astro-ph.IM

keywords Tully-Fisher relationstar-forming galaxiesgravitational lensinggalaxy kinematicsredshift evolutionbaryonic massintegral field spectroscopy

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The pith

The baryonic Tully-Fisher relation for star-forming galaxies at z~1 shows no evolution in zero-point compared to the local universe, while the stellar-mass version shifts by 0.42 dex.

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

The paper presents a 3D forward-modeling method that folds gravitational lensing deflections directly into the GalPaK3D algorithm to recover morpho-kinematic parameters of background galaxies. Applied to 95 rotationally supported, strongly lensed star-forming galaxies from the MUSE Lensing Cluster survey, the technique yields reliable rotation velocities even at modest magnifications. The resulting measurements show a clear downward shift in the zero-point of the stellar-mass Tully-Fisher relation relative to z=0, but the zero-point of the baryonic-mass relation (stars plus cold gas) remains statistically unchanged. This pattern indicates that the growing cold-gas reservoir at higher redshift fully offsets the decline in stellar mass at fixed rotation speed.

Core claim

Restricting the sample to 95 rotationally supported SFGs with well-constrained velocities, the analysis finds a significant evolution of the sTFR zero-point (Δb^sTFR = -0.42^{+0.05}_{-0.05} dex in stellar mass) but no detectable evolution of the bTFR zero-point (Δb^bTFR = 0.00^{+0.06}_{-0.06} dex in baryonic mass) relative to z≈0. The results are consistent with a mild evolution of the stellar-to-halo mass ratio and support the view that the sTFR has evolved only weakly over the past ~8 Gyr aside from shifts driven by the redshift dependence of halo-defining quantities.

What carries the argument

The 3D forward-modelling pipeline that incorporates lensing deflections into the GalPaK3D algorithm to constrain source parameters while correcting for differential magnification and beam smearing.

If this is right

The stellar-to-halo mass ratio evolves only mildly between z~1 and today.
The stellar Tully-Fisher relation evolves weakly over ~8 Gyr once halo-defining quantities such as critical density are accounted for.
The rising cold-gas fraction at higher redshift exactly compensates the observed change in the stellar component.

Where Pith is reading between the lines

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

Baryonic mass assembly appears more stable than stellar mass assembly alone across cosmic time.
Similar 3D lensing-corrected modeling applied to higher-redshift or lower-mass samples could test whether the compensation persists beyond z~1.

Load-bearing premise

The 95 selected galaxies are representative of the overall star-forming population at z~1 and the modeling fully removes biases from differential magnification and beam smearing for every object.

What would settle it

An independent measurement of the baryonic Tully-Fisher zero-point at z~1 using non-lensed integral-field spectroscopy on a comparable sample that finds a nonzero shift would contradict the no-evolution result.

read the original abstract

In a series of papers on lensed kinematics, we seek to combine the sensitivity of 3D forward modelling to low signal-to-noise ratio outskirts with the enhanced spatial resolution of cluster lensing. In this first paper, we (i) present and validate our methodology, which directly constrains the source parameters by incorporating lensing deflections into the $\texttt{GalPaK}^\texttt{3D}$ forward-modelling algorithm, and (ii) investigate the evolution of the stellar-mass and baryonic-mass Tully-Fisher relations (sTFR and bTFR) since $z \sim 1$. We define a robust sample of strongly lensed star-forming galaxies (SFGs) from the MUSE Lensing Cluster survey, spanning magnifications $\mu = 1.4 - 12.4$ and stellar masses $M_\star = 10^{8.1} - 10^{10.3} M_\odot$. Using a series of mock galaxies, we find that our method is significantly more reliable at recovering morpho-kinematic properties than approaches that ignore differential magnification, even for relatively modest magnifications ($\mu < 6$). Restricting the analysis to 95 rotationally supported SFGs with well-constrained velocities, we find a significant evolution of the sTFR zero-point ($\Delta b^\mathrm{sTFR} = -0.42^{+0.05}_{-0.05}~\mathrm{dex}$ in stellar mass) but no detectable evolution of the bTFR zero-point ($\Delta b^\mathrm{bTFR} = 0.00^{+0.06}_{-0.06}~\mathrm{dex}$ in baryonic mass) relative to $z \approx 0$. Our results are consistent with a mild evolution of the stellar-to-halo mass ratio and support the view that the sTFR has evolved only weakly over the past $\sim 8$ Gyr, aside from shifts driven by the redshift dependence of halo-defining quantities such as the critical density and overdensity. The absence of detectable evolution in the bTFR zero-point suggests that the increasing contribution of cold gas mass at higher redshift fully compensates the evolution observed in the stellar component alone. [abridged]

Editorial analysis

A structured set of objections, weighed in public.

Desk editor's note, referee report, simulated authors' rebuttal, and a circularity audit. Tearing a paper down is the easy half of reading it; the pith above is the substance, this is the friction.

Desk Editor's Note private letter to a colleague

Lensing-aware 3D modeling recovers better velocities for z~1 galaxies and shows the stellar TFR zero-point shifting while the baryonic one stays flat.

read the letter

The main thing to know is that folding lensing deflections straight into GalPaK3D improves recovery of morpho-kinematic parameters on lensed MUSE data, and the resulting sample of 95 rotationally supported galaxies at z~1 shows a 0.42 dex shift in the stellar TFR zero-point but none in the baryonic TFR. The method is the clearest advance: mocks confirm it handles differential magnification better than the usual ignore-lensing route, even down to mu around 6, which matters for cluster-lensed IFU work. The TFR result itself is a useful data point because it ties the lack of baryonic evolution to rising cold-gas fractions offsetting stellar-mass changes. The selection step that keeps only the 95 galaxies with well-constrained velocities is the soft spot. That cut comes after modeling, so it could quietly drop systems with higher turbulence or residual magnification effects that the mocks do not fully capture; without the rejected fraction or a test relaxing the cut, the reported deltas are harder to treat as fully representative. The error bars look small, but the abstract gives no covariance details or alternative-model checks, so the central claim sits on moderate rather than ironclad footing. This paper is for groups working on high-redshift scaling relations and lensed kinematics. The technical step is solid enough to deserve referee time, even if the numbers will need robustness tests in revision.

Referee Report

2 major / 2 minor

Summary. The paper introduces a 3D morpho-kinematic forward-modeling method that folds lensing deflections directly into the GalPaK3D algorithm. After validating the approach on mock galaxies (showing improved recovery of rotation velocities and masses relative to non-lensing fits even at μ < 6), the authors apply it to a MUSE lensing-cluster sample and restrict to 95 rotationally supported SFGs with well-constrained velocities. They report a significant zero-point shift in the stellar-mass TFR (Δb^sTFR = −0.42^{+0.05}_{-0.05} dex) but no detectable shift in the baryonic-mass TFR (Δb^bTFR = 0.00^{+0.06}_{-0.06} dex) relative to z ≈ 0, interpreting the difference as compensation by increased cold-gas mass at higher redshift.

Significance. If the selection and modeling biases are fully controlled, the result would tighten constraints on the redshift evolution of the stellar-to-halo mass ratio and demonstrate that the baryonic TFR remains stable once gas content is included. The mock-based validation of the lensing-aware modeling is a clear methodological strength.

major comments (2)

[abstract and results section] The post-modeling restriction to 95 galaxies with 'well-constrained velocities' (abstract and results section) is load-bearing for the reported Δb^sTFR and Δb^bTFR values. No fraction of rejected objects is stated, nor is a stability test provided when the velocity-constraint threshold is relaxed; the mocks do not explicitly propagate this cut into the population-level TFR bias estimate.
[results section] The zero-point shifts are presented without accompanying covariance matrices or full error budgets that include the joint uncertainty from individual magnification factors, velocity constraints, and the TFR fit itself (results section). This leaves the claim of 'no detectable evolution' in the bTFR only moderately anchored.

minor comments (2)

[methods] Define the exact functional form of the sTFR and bTFR (including the pivot mass and slope assumptions) in a dedicated methods subsection so that the zero-point shifts can be reproduced from the tabulated data.
[validation section] Add direct side-by-side panels in the mock-recovery figures comparing the lensing-aware and lensing-ignored fits for all key parameters (V_circ, M_star, M_bary) with quantitative bias and scatter metrics.

Simulated Author's Rebuttal

2 responses · 0 unresolved

We thank the referee for their constructive and detailed review. We address each major comment below and will incorporate revisions to improve the clarity and robustness of the analysis.

read point-by-point responses

Referee: [abstract and results section] The post-modeling restriction to 95 galaxies with 'well-constrained velocities' (abstract and results section) is load-bearing for the reported Δb^sTFR and Δb^bTFR values. No fraction of rejected objects is stated, nor is a stability test provided when the velocity-constraint threshold is relaxed; the mocks do not explicitly propagate this cut into the population-level TFR bias estimate.

Authors: We agree that the sample selection details require greater transparency. In the revised manuscript we will explicitly report the fraction of galaxies excluded by the velocity-constraint criterion. We will also add a stability test in which the threshold is relaxed and the resulting changes to the TFR zero-point shifts are quantified. Finally, we will extend the mock validation to propagate the post-modeling selection cut through to the population-level TFR bias estimate, confirming that the reported shifts remain robust. revision: yes
Referee: [results section] The zero-point shifts are presented without accompanying covariance matrices or full error budgets that include the joint uncertainty from individual magnification factors, velocity constraints, and the TFR fit itself (results section). This leaves the claim of 'no detectable evolution' in the bTFR only moderately anchored.

Authors: We acknowledge that a fuller propagation of uncertainties would strengthen the presentation. In the revision we will include the covariance matrix of the TFR fit parameters and provide an explicit error budget that jointly accounts for uncertainties in magnification, velocity constraints, and the fitting procedure. This will allow a more quantitative assessment of the significance of the baryonic TFR zero-point shift. revision: yes

Circularity Check

0 steps flagged

No significant circularity in TFR zero-point evolution measurement

full rationale

The paper's chain proceeds by forward-modeling lensed MUSE data with GalPaK3D plus lensing deflections to recover V_circ and masses for 95 selected galaxies, then fitting the sTFR and bTFR zero-points and differencing them against external z≈0 relations. These Δb values are direct empirical differences from the modeled observables; they are not defined in terms of the fit itself, nor do they reduce to any self-citation or ansatz imported from prior author work. Mock validation of the modeling is independent of the final TFR comparison. No load-bearing step matches the enumerated circularity patterns.

Axiom & Free-Parameter Ledger

1 free parameters · 1 axioms · 0 invented entities

Ledger populated from abstract only; full paper likely contains additional fitting parameters inside GalPaK3D and lensing models.

free parameters (1)

individual galaxy magnification
Magnification values (1.4-12.4) are derived from lens models and enter the forward modeling; their uncertainties propagate into the TFR fits.

axioms (1)

domain assumption Selected galaxies are rotationally supported disks with negligible non-circular motions
The sample is restricted to 95 objects with well-constrained velocities under this assumption.

pith-pipeline@v0.9.0 · 5780 in / 1472 out tokens · 34354 ms · 2026-05-14T21:43:29.570007+00:00 · methodology

discussion (0)

Forward citations

Cited by 1 Pith paper

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astro-ph.GA 2026-04 unverdicted novelty 7.0

The radial acceleration relation persists at intermediate redshifts but with a characteristic acceleration scale that increases linearly with redshift.