A Compressed-Observable Audit of Late-Time Cosmological Tension Projections
Andrew Morton · Public preprint · Descriptive data-product audit
Compares published lensing data products in a common descriptive amplitude coordinate and tests the limits of a universal compressed summary.
Abstract
High-precision cosmological probes show persistent, probe-dependent late-time offsets, including the H₀ and S₈ ≡ σ₈(Ωₘ/0.3)¹ᐟ² tensions. This paper introduces a deliberately restricted compressed-observable diagnostic in which public late-time data products are projected onto an effective compressed amplitude coordinate s. The coordinate is descriptive rather than model-level: agreement between probes is interpreted only as a necessary, not sufficient, condition for any single-factor compressed description. Using publicly released strong-lens time-delay products and weak-lensing compressed amplitudes, the analysis finds s_lens = 0.916 ± 0.024, s_KiDS = 0.901 ± 0.030, and s_DES Y6 = 0.948 ± 0.021 for DES Y6 3 × 2pt, with DES Y6 cosmic shear alone giving s = 0.941 ± 0.025. The lens–KiDS comparison is the strongest cross-product compatibility, with posterior overlap O = 0.765 and shift proxy 0.39σ. DES Y6 remains below the plotted CMB/reference normalization s = 1 under the adopted baseline compression, but occupies a higher-amplitude region: lens–DES Y6 3 × 2pt gives O = 0.460 and 1.04σ, while KiDS–DES Y6 3 × 2pt gives O = 0.339 and 1.31σ. The diagnostic therefore disfavors a literal universal constant-s compressed description across all released products. The more robust conclusion is that selected late-time probes can be compared within an amplitude-compression coordinate whose effective value is product- and kernel-dependent. The construction is intentionally not a modified-cosmology likelihood reinterpretation; it is a reproducible audit of whether released late-time products align along a shared compressed amplitude direction. Any physical interpretation would require full likelihood-level propagation through distances, growth, lensing kernels, intrinsic alignments, baryonic feedback, and nuisance parameters. The accompanying notebook is presented as a reproducible compression of published offsets, not as an estimator of a physical cosmological parameter.
Scope
The analysis audits released data products. Its amplitude coordinate is descriptive; a physical cosmological interpretation requires full likelihood-level propagation through distances, growth and nuisance parameters.
Paper and supporting files
The Zenodo record includes a companion notebook, numerical tables, figures, source-status information and provenance.
Read the current paper and supporting files on Zenodo
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Abstract checked 28 August 2026 · public release 12 May 2026.