{"paper":{"title":"Comparing cosmic shear nulling methods for Stage-IV surveys","license":"http://creativecommons.org/licenses/by/4.0/","headline":"Nulling strategies can substantially reduce bias on S8 and dark energy parameters in cosmic shear measurements.","cross_cats":[],"primary_cat":"astro-ph.CO","authors_text":"Alex Hall, Naomi Clare Robertson","submitted_at":"2025-12-17T17:12:43Z","abstract_excerpt":"We present an analysis comparing nulling strategies for reducing the impact of baryon feedback on cosmic shear measurements. We consider three different approaches which aim to `null' the high-$k$ modes using transformations applied to the data vector: the Bernardeau-Nishimichi-Taruya (BNT) transform which operates on the lensing field, a new implementation of an LU factorisation of the discretized Limber integral (LUnul) which operates on the lensing two-point statistics, and finally a method which uses a correlated LSS tracers to suppress contributions from lower redshifts (cross-correlation"},"claims":{"count":4,"items":[{"kind":"strongest_claim","text":"We find that the nulling techniques considered can have a large impact on reducing the bias on S8 and Dark Energy parameters.","source":"verdict.strongest_claim","status":"machine_extracted","claim_id":"C1","attestation":"unclaimed"},{"kind":"weakest_assumption","text":"The Fisher forecast model accurately represents the bias reduction from nulling without needing full end-to-end simulations or real data validation, and the assumed baryon feedback model matches reality.","source":"verdict.weakest_assumption","status":"machine_extracted","claim_id":"C2","attestation":"unclaimed"},{"kind":"one_line_summary","text":"BNT, LUnul, and cross-correlation nulling methods reduce bias on S8 and dark energy parameters in cosmic shear Fisher forecasts, with LUnul most aggressive but at cost of precision.","source":"verdict.one_line_summary","status":"machine_extracted","claim_id":"C3","attestation":"unclaimed"},{"kind":"headline","text":"Nulling strategies can substantially reduce bias on S8 and dark energy parameters in cosmic shear measurements.","source":"verdict.pith_extraction.headline","status":"machine_extracted","claim_id":"C4","attestation":"unclaimed"}],"snapshot_sha256":"c4c18ff05c8c003333afa6fb215d1e1a5fb1bb675f288dcf00c7bb383d545435"},"source":{"id":"2512.15604","kind":"arxiv","version":2},"verdict":{"id":"286532e2-0b78-47b5-b658-8f7366800fc1","model_set":{"reader":"grok-4.3"},"created_at":"2026-05-16T21:20:01.975605Z","strongest_claim":"We find that the nulling techniques considered can have a large impact on reducing the bias on S8 and Dark Energy parameters.","one_line_summary":"BNT, LUnul, and cross-correlation nulling methods reduce bias on S8 and dark energy parameters in cosmic shear Fisher forecasts, with LUnul most aggressive but at cost of precision.","pipeline_version":"pith-pipeline@v0.9.0","weakest_assumption":"The Fisher forecast model accurately represents the bias reduction from nulling without needing full end-to-end simulations or real data validation, and the assumed baryon feedback model matches reality.","pith_extraction_headline":"Nulling strategies can substantially reduce bias on S8 and dark energy parameters in cosmic shear measurements."},"integrity":{"clean":true,"summary":{"advisory":0,"critical":0,"by_detector":{},"informational":0},"endpoint":"/pith/2512.15604/integrity.json","findings":[],"available":true,"detectors_run":[],"snapshot_sha256":"c28c3603d3b5d939e8dc4c7e95fa8dfce3d595e45f758748cecf8e644a296938"},"references":{"count":1,"sample":[{"doi":"","year":2022,"title":"arXiv:2404.06098","work_id":"f0473644-ad99-4edb-9f42-c63ec2f0c1e4","ref_index":1,"cited_arxiv_id":"","is_internal_anchor":false}],"resolved_work":1,"snapshot_sha256":"daaaddaca948973c227002adbb743ce851825b7225b9f87c04866c3326293d99","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"}