{"record_type":"pith_number_record","schema_url":"https://pith.science/schemas/pith-number/v1.json","pith_number":"pith:2015:YJW2OCMIXT7HD7SLNCBVIBUBDK","short_pith_number":"pith:YJW2OCMI","schema_version":"1.0","canonical_sha256":"c26da70988bcfe71fe4b68835406811a92a6afd2f713e40d48d74de79218b3c5","source":{"kind":"arxiv","id":"1509.08463","version":2},"attestation_state":"computed","paper":{"title":"Eliminating the optical depth nuisance from the CMB with 21 cm cosmology","license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","headline":"","cross_cats":[],"primary_cat":"astro-ph.CO","authors_text":"Aaron R. Parsons, Adrian Liu, Blake D. Sherwin, Jonathan R. Pritchard, Rupert Allison, Uro\\v{s} Seljak","submitted_at":"2015-09-28T20:09:38Z","abstract_excerpt":"Amongst standard model parameters that are constrained by cosmic microwave background (CMB) observations, the optical depth $\\tau$ stands out as a nuisance parameter. While $\\tau$ provides some crude limits on reionization, it also degrades constraints on other cosmological parameters. Here we explore how 21 cm cosmology---as a direct probe of reionization---can be used to independently predict $\\tau$ in an effort to improve CMB parameter constraints. We develop two complementary schemes for doing so. The first uses 21 cm power spectrum observations in conjunction with semi-analytic simulation"},"verification_status":{"content_addressed":true,"pith_receipt":true,"author_attested":false,"weak_author_claims":0,"strong_author_claims":0,"externally_anchored":false,"storage_verified":false,"citation_signatures":0,"replication_records":0,"graph_snapshot":true,"references_resolved":false,"formal_links_present":false},"canonical_record":{"source":{"id":"1509.08463","kind":"arxiv","version":2},"metadata":{"license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","primary_cat":"astro-ph.CO","submitted_at":"2015-09-28T20:09:38Z","cross_cats_sorted":[],"title_canon_sha256":"dd5bb60621b505cb4efeda6641b1076a2ef50b878e1143d283edb967e9873950","abstract_canon_sha256":"8eb2f167926580615e1a2ec4ef83cc8b939baa9ccb94662dc59193573802b2be"},"schema_version":"1.0"},"receipt":{"kind":"pith_receipt","key_id":"pith-v1-2026-05","algorithm":"ed25519","signed_at":"2026-05-18T01:20:16.752240Z","signature_b64":"fnHiOj3230PtdKJFJjc1yTXlYXTOH9pMEtsY3OPbgIhpZ5kE+9mOSLbm60yg026jsJi1zrB5vtZiq92IrivkDg==","signed_message":"canonical_sha256_bytes","builder_version":"pith-number-builder-2026-05-17-v1","receipt_version":"0.3","canonical_sha256":"c26da70988bcfe71fe4b68835406811a92a6afd2f713e40d48d74de79218b3c5","last_reissued_at":"2026-05-18T01:20:16.751689Z","signature_status":"signed_v1","first_computed_at":"2026-05-18T01:20:16.751689Z","public_key_fingerprint":"8d4b5ee74e4693bcd1df2446408b0d54"},"graph_snapshot":{"paper":{"title":"Eliminating the optical depth nuisance from the CMB with 21 cm cosmology","license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","headline":"","cross_cats":[],"primary_cat":"astro-ph.CO","authors_text":"Aaron R. Parsons, Adrian Liu, Blake D. Sherwin, Jonathan R. Pritchard, Rupert Allison, Uro\\v{s} Seljak","submitted_at":"2015-09-28T20:09:38Z","abstract_excerpt":"Amongst standard model parameters that are constrained by cosmic microwave background (CMB) observations, the optical depth $\\tau$ stands out as a nuisance parameter. While $\\tau$ provides some crude limits on reionization, it also degrades constraints on other cosmological parameters. Here we explore how 21 cm cosmology---as a direct probe of reionization---can be used to independently predict $\\tau$ in an effort to improve CMB parameter constraints. We develop two complementary schemes for doing so. The first uses 21 cm power spectrum observations in conjunction with semi-analytic simulation"},"claims":{"count":0,"items":[],"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"source":{"id":"1509.08463","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":""},"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"},"aliases":[{"alias_kind":"arxiv","alias_value":"1509.08463","created_at":"2026-05-18T01:20:16.751773+00:00"},{"alias_kind":"arxiv_version","alias_value":"1509.08463v2","created_at":"2026-05-18T01:20:16.751773+00:00"},{"alias_kind":"doi","alias_value":"10.48550/arxiv.1509.08463","created_at":"2026-05-18T01:20:16.751773+00:00"},{"alias_kind":"pith_short_12","alias_value":"YJW2OCMIXT7H","created_at":"2026-05-18T12:29:50.041715+00:00"},{"alias_kind":"pith_short_16","alias_value":"YJW2OCMIXT7HD7SL","created_at":"2026-05-18T12:29:50.041715+00:00"},{"alias_kind":"pith_short_8","alias_value":"YJW2OCMI","created_at":"2026-05-18T12:29:50.041715+00:00"}],"events":[],"event_summary":{},"paper_claims":[],"inbound_citations":{"count":1,"internal_anchor_count":1,"sample":[{"citing_arxiv_id":"2605.18939","citing_title":"The Lumina Project: CMB Optical Depth Fluctuations from Patchy Reionization","ref_index":120,"is_internal_anchor":true}]},"formal_canon":{"evidence_count":0,"sample":[],"anchors":[]},"links":{"html":"https://pith.science/pith/YJW2OCMIXT7HD7SLNCBVIBUBDK","json":"https://pith.science/pith/YJW2OCMIXT7HD7SLNCBVIBUBDK.json","graph_json":"https://pith.science/api/pith-number/YJW2OCMIXT7HD7SLNCBVIBUBDK/graph.json","events_json":"https://pith.science/api/pith-number/YJW2OCMIXT7HD7SLNCBVIBUBDK/events.json","paper":"https://pith.science/paper/YJW2OCMI"},"agent_actions":{"view_html":"https://pith.science/pith/YJW2OCMIXT7HD7SLNCBVIBUBDK","download_json":"https://pith.science/pith/YJW2OCMIXT7HD7SLNCBVIBUBDK.json","view_paper":"https://pith.science/paper/YJW2OCMI","resolve_alias":"https://pith.science/api/pith-number/resolve?arxiv=1509.08463&json=true","fetch_graph":"https://pith.science/api/pith-number/YJW2OCMIXT7HD7SLNCBVIBUBDK/graph.json","fetch_events":"https://pith.science/api/pith-number/YJW2OCMIXT7HD7SLNCBVIBUBDK/events.json","actions":{"anchor_timestamp":"https://pith.science/pith/YJW2OCMIXT7HD7SLNCBVIBUBDK/action/timestamp_anchor","attest_storage":"https://pith.science/pith/YJW2OCMIXT7HD7SLNCBVIBUBDK/action/storage_attestation","attest_author":"https://pith.science/pith/YJW2OCMIXT7HD7SLNCBVIBUBDK/action/author_attestation","sign_citation":"https://pith.science/pith/YJW2OCMIXT7HD7SLNCBVIBUBDK/action/citation_signature","submit_replication":"https://pith.science/pith/YJW2OCMIXT7HD7SLNCBVIBUBDK/action/replication_record"}},"created_at":"2026-05-18T01:20:16.751773+00:00","updated_at":"2026-05-18T01:20:16.751773+00:00"}