{"record_type":"pith_number_record","schema_url":"https://pith.science/schemas/pith-number/v1.json","pith_number":"pith:2022:WRDHLZMZ5AJO4ZNOC43B4PJJ2B","short_pith_number":"pith:WRDHLZMZ","schema_version":"1.0","canonical_sha256":"b44675e599e812ee65ae17361e3d29d05183dc3605388b36ab8b4f11898afc60","source":{"kind":"arxiv","id":"2208.14675","version":2},"attestation_state":"computed","paper":{"title":"A Semi-blind PCA-based Foreground Subtraction Method for 21 cm Intensity Mapping","license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","headline":"","cross_cats":["astro-ph.IM"],"primary_cat":"astro-ph.CO","authors_text":"Shifan Zuo (Tsinghua), Xuelei Chen (NAOC), Yi Mao (Tsinghua)","submitted_at":"2022-08-31T08:01:08Z","abstract_excerpt":"The Principal Component Analysis (PCA) method and the Singular Value Decomposition (SVD) method are widely used for foreground subtraction in 21 cm intensity mapping experiments. We show their equivalence, and point out that the condition for completely clean separation of foregrounds and cosmic 21 cm signal using the PCA/SVD is unrealistic. We propose a PCA-based foreground subtraction method, dubbed \"Singular Vector Projection (SVP)\" method, which exploits a priori information of the left and/or right singular vectors of the foregrounds. We demonstrate with simulation tests that this new, se"},"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":"2208.14675","kind":"arxiv","version":2},"metadata":{"license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","primary_cat":"astro-ph.CO","submitted_at":"2022-08-31T08:01:08Z","cross_cats_sorted":["astro-ph.IM"],"title_canon_sha256":"114501fe04328b3939d5725dc05b54fe32d62a0393a649112808ea12d25a3bf8","abstract_canon_sha256":"01c77fbf369a581d521ffe4f4928678a357bc41750a7f071366ac320db7eeaae"},"schema_version":"1.0"},"receipt":{"kind":"pith_receipt","key_id":"pith-v1-2026-05","algorithm":"ed25519","signed_at":"2026-07-05T05:48:01.091784Z","signature_b64":"F07OJWM0BDedHjyNYLLpnskJVnfJwqDJ5Kgg22yYj/r0YqE8z8XFpxxtu4aONdtoPHR0/f+I4JMbQmcPtApvAw==","signed_message":"canonical_sha256_bytes","builder_version":"pith-number-builder-2026-05-17-v1","receipt_version":"0.3","canonical_sha256":"b44675e599e812ee65ae17361e3d29d05183dc3605388b36ab8b4f11898afc60","last_reissued_at":"2026-07-05T05:48:01.091360Z","signature_status":"signed_v1","first_computed_at":"2026-07-05T05:48:01.091360Z","public_key_fingerprint":"8d4b5ee74e4693bcd1df2446408b0d54"},"graph_snapshot":{"paper":{"title":"A Semi-blind PCA-based Foreground Subtraction Method for 21 cm Intensity Mapping","license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","headline":"","cross_cats":["astro-ph.IM"],"primary_cat":"astro-ph.CO","authors_text":"Shifan Zuo (Tsinghua), Xuelei Chen (NAOC), Yi Mao (Tsinghua)","submitted_at":"2022-08-31T08:01:08Z","abstract_excerpt":"The Principal Component Analysis (PCA) method and the Singular Value Decomposition (SVD) method are widely used for foreground subtraction in 21 cm intensity mapping experiments. We show their equivalence, and point out that the condition for completely clean separation of foregrounds and cosmic 21 cm signal using the PCA/SVD is unrealistic. We propose a PCA-based foreground subtraction method, dubbed \"Singular Vector Projection (SVP)\" method, which exploits a priori information of the left and/or right singular vectors of the foregrounds. We demonstrate with simulation tests that this new, se"},"claims":{"count":0,"items":[],"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"source":{"id":"2208.14675","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/2208.14675/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"},"aliases":[{"alias_kind":"arxiv","alias_value":"2208.14675","created_at":"2026-07-05T05:48:01.091420+00:00"},{"alias_kind":"arxiv_version","alias_value":"2208.14675v2","created_at":"2026-07-05T05:48:01.091420+00:00"},{"alias_kind":"doi","alias_value":"10.48550/arxiv.2208.14675","created_at":"2026-07-05T05:48:01.091420+00:00"},{"alias_kind":"pith_short_12","alias_value":"WRDHLZMZ5AJO","created_at":"2026-07-05T05:48:01.091420+00:00"},{"alias_kind":"pith_short_16","alias_value":"WRDHLZMZ5AJO4ZNO","created_at":"2026-07-05T05:48:01.091420+00:00"},{"alias_kind":"pith_short_8","alias_value":"WRDHLZMZ","created_at":"2026-07-05T05:48:01.091420+00:00"}],"events":[],"event_summary":{},"paper_claims":[],"inbound_citations":{"count":2,"internal_anchor_count":0,"sample":[{"citing_arxiv_id":"2604.07327","citing_title":"Primordial magnetic fields in the light of upcoming post-EoR Lyman-$\\alpha$ and 21-cm observations","ref_index":79,"is_internal_anchor":false},{"citing_arxiv_id":"2604.15287","citing_title":"Neutrino self-interactions in post-reionization era: Lyman-$\\alpha$, 21-cm and cross-spectra","ref_index":82,"is_internal_anchor":false}]},"formal_canon":{"evidence_count":0,"sample":[],"anchors":[]},"links":{"html":"https://pith.science/pith/WRDHLZMZ5AJO4ZNOC43B4PJJ2B","json":"https://pith.science/pith/WRDHLZMZ5AJO4ZNOC43B4PJJ2B.json","graph_json":"https://pith.science/api/pith-number/WRDHLZMZ5AJO4ZNOC43B4PJJ2B/graph.json","events_json":"https://pith.science/api/pith-number/WRDHLZMZ5AJO4ZNOC43B4PJJ2B/events.json","paper":"https://pith.science/paper/WRDHLZMZ"},"agent_actions":{"view_html":"https://pith.science/pith/WRDHLZMZ5AJO4ZNOC43B4PJJ2B","download_json":"https://pith.science/pith/WRDHLZMZ5AJO4ZNOC43B4PJJ2B.json","view_paper":"https://pith.science/paper/WRDHLZMZ","resolve_alias":"https://pith.science/api/pith-number/resolve?arxiv=2208.14675&json=true","fetch_graph":"https://pith.science/api/pith-number/WRDHLZMZ5AJO4ZNOC43B4PJJ2B/graph.json","fetch_events":"https://pith.science/api/pith-number/WRDHLZMZ5AJO4ZNOC43B4PJJ2B/events.json","actions":{"anchor_timestamp":"https://pith.science/pith/WRDHLZMZ5AJO4ZNOC43B4PJJ2B/action/timestamp_anchor","attest_storage":"https://pith.science/pith/WRDHLZMZ5AJO4ZNOC43B4PJJ2B/action/storage_attestation","attest_author":"https://pith.science/pith/WRDHLZMZ5AJO4ZNOC43B4PJJ2B/action/author_attestation","sign_citation":"https://pith.science/pith/WRDHLZMZ5AJO4ZNOC43B4PJJ2B/action/citation_signature","submit_replication":"https://pith.science/pith/WRDHLZMZ5AJO4ZNOC43B4PJJ2B/action/replication_record"}},"created_at":"2026-07-05T05:48:01.091420+00:00","updated_at":"2026-07-05T05:48:01.091420+00:00"}