{"record_type":"pith_number_record","schema_url":"https://pith.science/schemas/pith-number/v1.json","pith_number":"pith:2012:HUHVNFY64Z5CYC5DFMDGEVUCJY","short_pith_number":"pith:HUHVNFY6","schema_version":"1.0","canonical_sha256":"3d0f56971ee67a2c0ba32b066256824e204700fa28aba354ae9685eca317b36a","source":{"kind":"arxiv","id":"1204.2881","version":4},"attestation_state":"computed","paper":{"title":"Complete ionisation of the neutral gas: why there are so few detections of 21-cm hydrogen in high redshift radio galaxies and quasars","license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","headline":"","cross_cats":[],"primary_cat":"astro-ph.CO","authors_text":"M. T. Whiting, S. J. Curran","submitted_at":"2012-04-13T05:03:11Z","abstract_excerpt":"From the first published z > 3 survey of 21-cm absorption within the hosts of radio galaxies and quasars, we found an apparent dearth of cool neutral gas at high redshift. From a detailed analysis of the photometry, each object is found to have a 1216 A continuum luminosity in excess of L ~1e23 W/Hz, a critical value above which 21-cm has never been detected at any redshift. At these wavelengths, and below, hydrogen is excited above the ground state so that it cannot absorb in 21-cm. In order to apply the equation of photoionsation equilibrium, we demonstrate that this critical value also appl"},"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":"1204.2881","kind":"arxiv","version":4},"metadata":{"license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","primary_cat":"astro-ph.CO","submitted_at":"2012-04-13T05:03:11Z","cross_cats_sorted":[],"title_canon_sha256":"4251da80570b1a2d7fe00f1cc23ce66a78935059cc9098f2feaeabcaff8c60b2","abstract_canon_sha256":"3e6a0cad1b35ce70001c5a51afada56aed49c56a07be09fa5877ccff50f79faa"},"schema_version":"1.0"},"receipt":{"kind":"pith_receipt","key_id":"pith-v1-2026-05","algorithm":"ed25519","signed_at":"2026-05-18T01:57:52.879989Z","signature_b64":"xIRGiNh5XCU7Y5xpDiZDgehxOEw+pJwzgFIPbHENB+n2YdvkAAPBKnqfGV7PocogsYFGaadiIM8C7hf6nXLABg==","signed_message":"canonical_sha256_bytes","builder_version":"pith-number-builder-2026-05-17-v1","receipt_version":"0.3","canonical_sha256":"3d0f56971ee67a2c0ba32b066256824e204700fa28aba354ae9685eca317b36a","last_reissued_at":"2026-05-18T01:57:52.879423Z","signature_status":"signed_v1","first_computed_at":"2026-05-18T01:57:52.879423Z","public_key_fingerprint":"8d4b5ee74e4693bcd1df2446408b0d54"},"graph_snapshot":{"paper":{"title":"Complete ionisation of the neutral gas: why there are so few detections of 21-cm hydrogen in high redshift radio galaxies and quasars","license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","headline":"","cross_cats":[],"primary_cat":"astro-ph.CO","authors_text":"M. T. Whiting, S. J. Curran","submitted_at":"2012-04-13T05:03:11Z","abstract_excerpt":"From the first published z > 3 survey of 21-cm absorption within the hosts of radio galaxies and quasars, we found an apparent dearth of cool neutral gas at high redshift. From a detailed analysis of the photometry, each object is found to have a 1216 A continuum luminosity in excess of L ~1e23 W/Hz, a critical value above which 21-cm has never been detected at any redshift. At these wavelengths, and below, hydrogen is excited above the ground state so that it cannot absorb in 21-cm. In order to apply the equation of photoionsation equilibrium, we demonstrate that this critical value also appl"},"claims":{"count":0,"items":[],"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"source":{"id":"1204.2881","kind":"arxiv","version":4},"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":"1204.2881","created_at":"2026-05-18T01:57:52.879509+00:00"},{"alias_kind":"arxiv_version","alias_value":"1204.2881v4","created_at":"2026-05-18T01:57:52.879509+00:00"},{"alias_kind":"doi","alias_value":"10.48550/arxiv.1204.2881","created_at":"2026-05-18T01:57:52.879509+00:00"},{"alias_kind":"pith_short_12","alias_value":"HUHVNFY64Z5C","created_at":"2026-05-18T12:27:09.501522+00:00"},{"alias_kind":"pith_short_16","alias_value":"HUHVNFY64Z5CYC5D","created_at":"2026-05-18T12:27:09.501522+00:00"},{"alias_kind":"pith_short_8","alias_value":"HUHVNFY6","created_at":"2026-05-18T12:27:09.501522+00:00"}],"events":[],"event_summary":{},"paper_claims":[],"inbound_citations":{"count":1,"internal_anchor_count":1,"sample":[{"citing_arxiv_id":"2606.31546","citing_title":"Tracing Cold Gas in Absorption Across Cosmic Time with the SKA","ref_index":279,"is_internal_anchor":true}]},"formal_canon":{"evidence_count":0,"sample":[],"anchors":[]},"links":{"html":"https://pith.science/pith/HUHVNFY64Z5CYC5DFMDGEVUCJY","json":"https://pith.science/pith/HUHVNFY64Z5CYC5DFMDGEVUCJY.json","graph_json":"https://pith.science/api/pith-number/HUHVNFY64Z5CYC5DFMDGEVUCJY/graph.json","events_json":"https://pith.science/api/pith-number/HUHVNFY64Z5CYC5DFMDGEVUCJY/events.json","paper":"https://pith.science/paper/HUHVNFY6"},"agent_actions":{"view_html":"https://pith.science/pith/HUHVNFY64Z5CYC5DFMDGEVUCJY","download_json":"https://pith.science/pith/HUHVNFY64Z5CYC5DFMDGEVUCJY.json","view_paper":"https://pith.science/paper/HUHVNFY6","resolve_alias":"https://pith.science/api/pith-number/resolve?arxiv=1204.2881&json=true","fetch_graph":"https://pith.science/api/pith-number/HUHVNFY64Z5CYC5DFMDGEVUCJY/graph.json","fetch_events":"https://pith.science/api/pith-number/HUHVNFY64Z5CYC5DFMDGEVUCJY/events.json","actions":{"anchor_timestamp":"https://pith.science/pith/HUHVNFY64Z5CYC5DFMDGEVUCJY/action/timestamp_anchor","attest_storage":"https://pith.science/pith/HUHVNFY64Z5CYC5DFMDGEVUCJY/action/storage_attestation","attest_author":"https://pith.science/pith/HUHVNFY64Z5CYC5DFMDGEVUCJY/action/author_attestation","sign_citation":"https://pith.science/pith/HUHVNFY64Z5CYC5DFMDGEVUCJY/action/citation_signature","submit_replication":"https://pith.science/pith/HUHVNFY64Z5CYC5DFMDGEVUCJY/action/replication_record"}},"created_at":"2026-05-18T01:57:52.879509+00:00","updated_at":"2026-05-18T01:57:52.879509+00:00"}