{"paper":{"title":"Union Through UNITY: Cosmology with 2,000 SNe Using a Unified Bayesian Framework","license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","headline":"A compilation of 2087 Type Ia supernovae yields cosmological constraints showing weak tension with LambdaCDM.","cross_cats":[],"primary_cat":"astro-ph.CO","authors_text":"Alex G. Kim, Andy Fruchter, Chris Lidman, David Rubin, Eric Linder, Greg Aldering, Marc Betoule, Nao Suzuki, Pilar Ruiz-Lapuente, Saul Perlmutter, Xiaosheng Huang","submitted_at":"2023-11-20T19:00:01Z","abstract_excerpt":"Type Ia supernovae (SNe Ia) were instrumental in establishing the acceleration of the universe's expansion. By virtue of their combination of distance reach, precision, and prevalence, they continue to provide key cosmological constraints, complementing other cosmological probes. Individual SN surveys cover only over about a factor of two in redshift, so compilations of multiple SN datasets are strongly beneficial. We assemble an up-to-date \"Union\" compilation of 2087 cosmologically useful SNe Ia from 24 datasets (\"Union3\"). We take care to put all SNe on the same distance scale and update the"},"claims":{"count":4,"items":[{"kind":"strongest_claim","text":"We compute updated cosmological constraints with Union3 and UNITY1.5, finding weak 1.7--2.6 sigma tension with LambdaCDM and possible evidence for thawing dark energy (w0 > -1, wa < 0).","source":"verdict.strongest_claim","status":"machine_extracted","claim_id":"C1","attestation":"unclaimed"},{"kind":"weakest_assumption","text":"That all 24 datasets can be placed on a single consistent distance scale and that the UNITY1.5 model fully captures selection effects, outlier populations, and unexplained dispersion without residual biases.","source":"verdict.weakest_assumption","status":"machine_extracted","claim_id":"C2","attestation":"unclaimed"},{"kind":"one_line_summary","text":"Union3 compilation of 2087 SNe Ia with UNITY1.5 framework shows 1.7-2.6 sigma tension with LambdaCDM and possible thawing dark energy.","source":"verdict.one_line_summary","status":"machine_extracted","claim_id":"C3","attestation":"unclaimed"},{"kind":"headline","text":"A compilation of 2087 Type Ia supernovae yields cosmological constraints showing weak tension with LambdaCDM.","source":"verdict.pith_extraction.headline","status":"machine_extracted","claim_id":"C4","attestation":"unclaimed"}],"snapshot_sha256":"72b2ea6a6f9aee4dc3f01d088a32956babf97445c05fb6e509d74da29b30f261"},"source":{"id":"2311.12098","kind":"arxiv","version":4},"verdict":{"id":"8537abff-ce0e-4eaa-96be-0e93e97193a3","model_set":{"reader":"grok-4.3"},"created_at":"2026-05-15T19:32:57.321841Z","strongest_claim":"We compute updated cosmological constraints with Union3 and UNITY1.5, finding weak 1.7--2.6 sigma tension with LambdaCDM and possible evidence for thawing dark energy (w0 > -1, wa < 0).","one_line_summary":"Union3 compilation of 2087 SNe Ia with UNITY1.5 framework shows 1.7-2.6 sigma tension with LambdaCDM and possible thawing dark energy.","pipeline_version":"pith-pipeline@v0.9.0","weakest_assumption":"That all 24 datasets can be placed on a single consistent distance scale and that the UNITY1.5 model fully captures selection effects, outlier populations, and unexplained dispersion without residual biases.","pith_extraction_headline":"A compilation of 2087 Type Ia supernovae yields cosmological constraints showing weak tension with LambdaCDM."},"references":{"count":266,"sample":[{"doi":"10.1086/421365","year":2004,"title":"K., Ag¨ ueros, M","work_id":"75904ad3-fcd9-4903-8029-af362c1915cf","ref_index":1,"cited_arxiv_id":"","is_internal_anchor":false},{"doi":"10.1093/mnras/sty1939","year":2018,"title":"Abbott , T. M. C., Abdalla , F. B., Annis , J., et al. 2018, , 480, 3879, 10.1093/mnras/sty1939","work_id":"586f4dd0-7a78-4ab8-9034-e5a6f179d5c6","ref_index":2,"cited_arxiv_id":"","is_internal_anchor":false},{"doi":"10.3847/2041-8213/ab04fa","year":2019,"title":"Abbott , T. M. C., Allam , S., Andersen , P., et al. 2019, , 872, L30, 10.3847/2041-8213/ab04fa","work_id":"c5a039b9-5fee-4442-ab94-a42ec2571bdb","ref_index":3,"cited_arxiv_id":"","is_internal_anchor":false},{"doi":"10.3847/1538-4365/ac00b3","year":2021,"title":"Abbott , T. M. C., Adam \\'o w , M., Aguena , M., et al. 2021, , 255, 20, 10.3847/1538-4365/ac00b3","work_id":"8f92ad5b-f48d-4c13-aee8-bb93aa92b537","ref_index":4,"cited_arxiv_id":"","is_internal_anchor":false},{"doi":"10.1086/518864","year":2007,"title":"K., Ag \\\"u eros , M","work_id":"26716aae-ab50-431a-b40e-df87facd4095","ref_index":5,"cited_arxiv_id":"","is_internal_anchor":false}],"resolved_work":266,"snapshot_sha256":"9e3505358255411236151e19c7801b00d478fcf15d765031d6e95d5e69ae9ea4","internal_anchors":18},"formal_canon":{"evidence_count":2,"snapshot_sha256":"2f831fc76eeeeeb8deff56181b8e8e0dcad0641a4c765e2dbb83a95d97e8742f"},"author_claims":{"count":0,"strong_count":0,"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"builder_version":"pith-number-builder-2026-05-17-v1"}