{"paper":{"title":"$S_8$ from peculiar velocities: agreement with Planck for Tully--Fisher and supernovae, tension for the fundamental plane","license":"http://creativecommons.org/licenses/by/4.0/","headline":"","cross_cats":[],"primary_cat":"astro-ph.CO","authors_text":"Richard Stiskalek","submitted_at":"2025-09-24T15:25:11Z","abstract_excerpt":"Peculiar velocity measurements constrain the parameter combination $f\\sigma_8$, the product of the linear growth rate $f$ and the fluctuation amplitude $\\sigma_8$. Under the approximation that $f$ is a monotonic function of $\\Omega_{\\rm m}$, this can be related to $S_8 \\equiv \\sigma_8 \\sqrt{\\Omega_{\\rm m}/0.3}$, enabling direct comparison with weak lensing and cosmic microwave background results. We use three classes of direct-distance tracers -- the Tully--Fisher relation, the fundamental plane, and Type Ia supernovae -- to infer peculiar velocities. A unified hierarchical forward model joint"},"claims":{"count":0,"items":[],"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"source":{"id":"2509.20235","kind":"arxiv","version":2},"verdict":{"id":null,"model_set":{},"created_at":null,"strongest_claim":"","one_line_summary":"","pipeline_version":null,"weakest_assumption":"","pith_extraction_headline":""},"integrity":{"clean":true,"summary":{"advisory":0,"critical":0,"by_detector":{},"informational":0},"endpoint":"/pith/2509.20235/integrity.json","findings":[],"available":true,"detectors_run":[],"snapshot_sha256":"c28c3603d3b5d939e8dc4c7e95fa8dfce3d595e45f758748cecf8e644a296938"},"references":{"count":0,"sample":[],"resolved_work":0,"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57","internal_anchors":0},"formal_canon":{"evidence_count":0,"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"author_claims":{"count":0,"strong_count":0,"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"builder_version":"pith-number-builder-2026-05-17-v1"}