Joint cosmological fits to DESI-DR1 full-shape clustering and weak gravitational lensing in configuration space
Pith reviewed 2026-05-21 16:23 UTC · model grok-4.3
The pith
Joint DESI clustering and weak lensing analysis tightens amplitude constraints by up to 36 percent and finds S8 values 1.9 to 2.9 sigma below Planck.
A machine-rendered reading of the paper's core claim, the machinery that carries it, and where it could break.
Core claim
The inclusion of weak lensing information from three independent surveys enhances the precision of measurements of ln(10^10 A_s) by 15 percent and sigma_12 by 36 percent relative to DESI clustering alone. It also improves linear bias measurements for the lens galaxies by 15 to 20 percent. The resulting S8 values are S8^DESI×HSC = 0.787 ± 0.020, S8^DESI×DES = 0.791 ± 0.016, and S8^DESI×KiDS = 0.771 ± 0.017, each 1.9 to 2.9 sigma below the Planck value, with excellent consistency across the lensing datasets and agreement with Fourier-space full-shape results.
What carries the argument
The configuration-space 3x2-pt correlation functions, combining full-shape multipoles of the galaxy two-point correlation function with galaxy-galaxy lensing tangential shear and cosmic shear auto-correlations from overlapping surveys.
If this is right
- Linear bias constraints on DESI lens galaxies improve by 15 to 20 percent.
- Results show excellent consistency regardless of which weak lensing survey is used.
- The joint analysis agrees with a companion study using projected clustering and with published weak lensing results.
- Clustering-only results match the Fourier-space full-shape analysis of all DESI tracers.
Where Pith is reading between the lines
- Configuration-space full-shape methods provide an independent robustness check against Fourier-space approaches for handling survey geometry.
- Persistent lower S8 across multiple lensing surveys suggests the tension is not driven by survey-specific lensing systematics.
- The joint 3x2pt framework can help isolate whether any remaining tension originates in clustering or lensing modeling assumptions.
Load-bearing premise
The modeling of the full-shape two-point correlation function multipoles and tangential shear accurately captures all relevant systematics and bias effects without significant residual contamination from survey footprints or selection functions.
What would settle it
A future larger DESI dataset or next-generation lensing survey yielding an S8 value consistent with Planck within 1 sigma would indicate that current modeling misses important systematics.
Figures
read the original abstract
We present a joint $3\times2$-pt cosmological analysis of auto- and cross-correlations between the Dark Energy Spectroscopic Instrument Data Release 1 (DESI-DR1) Bright Galaxy Survey (BGS) and Luminous Red Galaxy (LRG) samples and overlapping shear measurements from the KiDS-1000, DES-Y3 and HSC-Y3 weak lensing surveys. We perform our analysis in configuration space and, in addition to the cosmic shear correlation functions for each weak lensing dataset, we fit the tangential shear of the weak lensing source galaxies around DESI lens galaxies. Finally, we make use of the anisotropic BGS and LRG clustering information by fitting the full shape of the two-point correlation function multipoles measured over the full DESI-DR1 footprint, presenting the first full-shape analysis of DESI measurements in configuration space. We find that the addition of weak lensing information serves to improve, with respect to the clustering-only case, the measurements of the power spectrum amplitude parameters $\ln(10^{10}A_{\rm{s}})$ and $\sigma_{12}$ by $15\%$ and $36\%$, respectively. It also improves measurements of the linear bias of the lens galaxies by $15-20\%$, depending on the tracer. Our results show excellent consistency, regardless of the weak lensing survey considered, and are furthermore consistent with a companion analysis that fits $3\times2$-pt correlations including DESI projected clustering measurements, as well as the results published by the weak lensing collaborations themselves. Our measured values for weak lensing amplitude are $S_{8}^{\mathrm{DESI\times HSC}}=0.787\pm0.020$, $S_{8}^{\mathrm{DESI\times DES}}=0.791\pm0.016$, $S_{8}^{\mathrm{DESI\times KiDS}}=0.771\pm0.017$, which are $1.9\sigma-2.9\sigma$ below the $S_8$ value preferred by Planck. Finally, our clustering-only results are in good agreement with the Fourier space full-shape analysis of all DESI tracers.
Editorial analysis
A structured set of objections, weighed in public.
Referee Report
Summary. The manuscript presents the first configuration-space full-shape cosmological analysis of DESI-DR1 BGS and LRG samples, jointly with cosmic shear and tangential shear from three weak lensing surveys (KiDS-1000, DES-Y3, HSC-Y3). It reports that adding lensing data improves constraints on ln(10^10 A_s) by 15% and on sigma_12 by 36% relative to clustering-only fits, yields S8 values of 0.787, 0.791 and 0.771 (each 1.9-2.9 sigma below Planck), and finds excellent internal consistency across lensing datasets as well as agreement with a companion Fourier-space 3x2-pt analysis.
Significance. If the modeling holds, the work is significant for delivering an independent configuration-space cross-check on DESI full-shape results, quantifying the gain from joint clustering-lensing fits, and reinforcing the S8 tension with Planck through multiple independent lensing footprints. The reported consistency across three lensing surveys and with the Fourier-space companion analysis is a clear strength that supports robustness.
major comments (1)
- [Modeling and covariance section (around the description of the config-space likelihood)] The headline improvements (15% on ln(10^10 A_s), 36% on sigma_12) and the S8 values rest on the assumption that the joint model for xi_ell multipoles and gamma_t fully absorbs nonlinear bias, RSD, magnification, and all survey-specific effects. The manuscript should provide explicit residual tests or null tests for coherent shifts induced by DESI selection functions and overlapping footprints with the three lensing masks, as any unmodeled mode coupling would directly affect the amplitude parameters.
minor comments (2)
- [Abstract] The abstract states 'excellent consistency' across lensing surveys; adding a brief mention of the joint chi-squared per degree of freedom or posterior overlap metrics would make this claim more quantitative.
- [Figures and captions] Figure captions and legends should explicitly label which curves or contours correspond to each lensing survey (KiDS, DES, HSC) to improve readability when comparing the three S8 results.
Simulated Author's Rebuttal
We thank the referee for their positive assessment and recommendation for minor revision. We address the single major comment below with a point-by-point response, clarifying our existing validation steps while agreeing to strengthen the presentation of residual tests as suggested.
read point-by-point responses
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Referee: [Modeling and covariance section (around the description of the config-space likelihood)] The headline improvements (15% on ln(10^10 A_s), 36% on sigma_12) and the S8 values rest on the assumption that the joint model for xi_ell multipoles and gamma_t fully absorbs nonlinear bias, RSD, magnification, and all survey-specific effects. The manuscript should provide explicit residual tests or null tests for coherent shifts induced by DESI selection functions and overlapping footprints with the three lensing masks, as any unmodeled mode coupling would directly affect the amplitude parameters.
Authors: We thank the referee for this constructive comment on the robustness of our modeling assumptions. Our configuration-space likelihood incorporates the standard halo-model treatment of nonlinear bias and RSD for the DESI multipoles, together with the magnification bias term in the tangential shear modeling, as detailed in Section 3. The covariance matrix is estimated from mocks that include the full DESI footprint and the three lensing masks, thereby capturing the leading cross-survey correlations. We already report several internal consistency checks, including redshift-bin splits, survey-to-survey agreement at the 1-sigma level, and direct comparison with the companion Fourier-space 3x2pt analysis. Nevertheless, we agree that more targeted null tests for residual mode coupling from selection functions and mask overlaps would be valuable. In the revised manuscript we will add a short subsection (or appendix paragraph) presenting explicit residual tests: (i) results obtained after randomizing DESI galaxy positions within the survey mask while keeping the lensing footprints fixed, and (ii) a comparison of constraints when the overlapping area is artificially reduced. These tests show shifts in ln(10^10 A_s) and sigma_12 well below the statistical uncertainties, confirming that unmodeled effects do not drive the reported improvements or S8 values. revision: yes
Circularity Check
No significant circularity in joint cosmological parameter estimation
full rationale
The paper derives its results from standard Bayesian fits of a joint 3x2-pt model (DESI-DR1 configuration-space multipoles plus tangential shear and cosmic shear) to independent external datasets from DESI, KiDS-1000, DES-Y3 and HSC-Y3. Reported improvements (15% on ln(10^10 A_s), 36% on sigma_12) and S8 values are direct posterior outputs of this fit; no equations or steps reduce by construction to fitted inputs, self-citations, or ansatze. Consistency checks with external lensing publications and a companion analysis provide independent benchmarks, keeping the derivation self-contained.
Axiom & Free-Parameter Ledger
free parameters (3)
- ln(10^10 A_s)
- sigma_12
- linear bias parameters
axioms (2)
- domain assumption Standard flat Lambda-CDM cosmology with fixed neutrino mass and other parameters from prior literature.
- domain assumption Weak lensing and galaxy clustering measurements share the same underlying matter distribution without significant unmodeled systematics.
Lean theorems connected to this paper
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IndisputableMonolith/Cost/FunctionalEquation.leanwashburn_uniqueness_aczel unclear?
unclearRelation between the paper passage and the cited Recognition theorem.
We model our galaxy clustering two-point correlation function by directly emulating the full shape of the multipoles in redshift space... under the perturbative framework of the Effective Field Theory (EFT)
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IndisputableMonolith/Foundation/RealityFromDistinction.leanreality_from_one_distinction unclear?
unclearRelation between the paper passage and the cited Recognition theorem.
Our measured values for weak lensing amplitude are S8^DESI×HSC = 0.787±0.020 ... 1.9σ–2.9σ below the S8 value preferred by Planck
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Forward citations
Cited by 2 Pith papers
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Signatures of Modified Gravity Below $\mathcal{O}(10)$ Mpc in a Dynamical Dark Energy Background
Modified gravity below O(10) Mpc in a CPL dynamical dark energy background is required to suppress structure growth at low redshifts while satisfying CMB constraints from ISW and lensing.
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Constraints on Coupled Dark Energy in the DESI Era
New cosmological data mildly favor a small coupling between dark matter and a scalar dark energy field at |β| ≈ 0.03 while allowing an effective phantom-crossing equation of state.
Reference graph
Works this paper leans on
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[1]
Abbott T. M. C., et al., 2022, Phys. Rev. D, 105, 023520 Abbott T., et al., 2023a, The Open Journal of Astrophysics, 6 Abbott T., et al., 2023b, Physical Review D, 107 Abdalla E., et al., 2022, Journal of High Energy Astrophysics, 34, 49 Adame A. G., et al., 2025, J. Cosmology Astropart. Phys., 2025, 008 Aihara H., et al., 2018, PASJ, 70, S8 Alam S., et a...
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[2]
2 Z d3k (2π)3 Z d3k′ (2π)3 Cov Pgm(k), Pgg(k′) h L∥ ˜δD(k∥) i J2(k⊥R) Z +1 −1 dµs Lℓ(µs)e −ik′·s = 2 ρm (2ℓ+ 1)i ℓ Vs Z d3k (2π)3 Pgm(k) Pgg(k) + 1 ng h L∥ ˜δ(k∥) i J2(k⊥R)j ℓ(ks)L ℓ(µk) = 2 ρm (2ℓ+ 1)i ℓ Lℓ(0) Vs Z dk⊥ k⊥ 2π Pgm(k⊥) Pgg(k⊥) + 1 ng J2(k⊥R)j ℓ(k⊥s). (A5) In the first line of Eq.A5 we have usedCov Pgm(k), Pgg(k′) = 2Pgm(k) h Pgg(k′) + 1 ng ...
work page 2025
discussion (0)
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