{"record_type":"pith_number_record","schema_url":"https://pith.science/schemas/pith-number/v1.json","pith_number":"pith:1999:D7GD4APIGYBV74GSKWQNB2GUO7","short_pith_number":"pith:D7GD4API","schema_version":"1.0","canonical_sha256":"1fcc3e01e836035ff0d255a0d0e8d477d8658697df11fc83cb5a3d6cba171e99","source":{"kind":"arxiv","id":"astro-ph/9912432","version":2},"attestation_state":"computed","paper":{"title":"The thermal history of the intergalactic medium","license":"","headline":"","cross_cats":[],"primary_cat":"astro-ph","authors_text":"George Efstathiou (Cambridge), Joop Schaye (Cambridge), Michael Rauch (ESO), Tom Theuns (MPA), Wallace L.W. Sargent (Caltech)","submitted_at":"1999-12-20T20:58:19Z","abstract_excerpt":"At redshifts z >~ 2, most of the baryons reside in the smooth intergalactic medium which is responsible for the low column density Lyman-alpha forest. This photoheated gas follows a tight temperature-density relation which introduces a cut-off in the distribution of widths of the Lyman-alpha absorption lines (b-parameters) as a function of column density. We have measured this cut-off in a sample of nine high resolution, high signal-to-noise quasar spectra, and determined the thermal evolution of the intergalactic medium in the redshift range 2.0-4.5. At redshift z ~ 3, the temperature at the "},"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":"astro-ph/9912432","kind":"arxiv","version":2},"metadata":{"license":"","primary_cat":"astro-ph","submitted_at":"1999-12-20T20:58:19Z","cross_cats_sorted":[],"title_canon_sha256":"6b277aa2da608f215395bfb3752bb918e6e41fe18bbc4dee93181efbfb525a55","abstract_canon_sha256":"d1164c61d9eee41df4b6aa7ddc102c46024ff890a92a862a81e5b242ca7f55d5"},"schema_version":"1.0"},"receipt":{"kind":"pith_receipt","key_id":"pith-v1-2026-05","algorithm":"ed25519","signed_at":"2026-07-04T16:12:02.975213Z","signature_b64":"uvKPcSCUa0WUvPZ1hxGHVx9bN8pJW7vq0ARNLGVjI8H9EgVxOG4/cZTndtLUa0PlrVQpJUZhtjZr+A+6+IluAQ==","signed_message":"canonical_sha256_bytes","builder_version":"pith-number-builder-2026-05-17-v1","receipt_version":"0.3","canonical_sha256":"1fcc3e01e836035ff0d255a0d0e8d477d8658697df11fc83cb5a3d6cba171e99","last_reissued_at":"2026-07-04T16:12:02.974685Z","signature_status":"signed_v1","first_computed_at":"2026-07-04T16:12:02.974685Z","public_key_fingerprint":"8d4b5ee74e4693bcd1df2446408b0d54"},"graph_snapshot":{"paper":{"title":"The thermal history of the intergalactic medium","license":"","headline":"","cross_cats":[],"primary_cat":"astro-ph","authors_text":"George Efstathiou (Cambridge), Joop Schaye (Cambridge), Michael Rauch (ESO), Tom Theuns (MPA), Wallace L.W. Sargent (Caltech)","submitted_at":"1999-12-20T20:58:19Z","abstract_excerpt":"At redshifts z >~ 2, most of the baryons reside in the smooth intergalactic medium which is responsible for the low column density Lyman-alpha forest. This photoheated gas follows a tight temperature-density relation which introduces a cut-off in the distribution of widths of the Lyman-alpha absorption lines (b-parameters) as a function of column density. We have measured this cut-off in a sample of nine high resolution, high signal-to-noise quasar spectra, and determined the thermal evolution of the intergalactic medium in the redshift range 2.0-4.5. At redshift z ~ 3, the temperature at the "},"claims":{"count":0,"items":[],"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"source":{"id":"astro-ph/9912432","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/astro-ph/9912432/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":"astro-ph/9912432","created_at":"2026-07-04T16:12:02.974746+00:00"},{"alias_kind":"arxiv_version","alias_value":"astro-ph/9912432v2","created_at":"2026-07-04T16:12:02.974746+00:00"},{"alias_kind":"doi","alias_value":"10.48550/arxiv.astro-ph/9912432","created_at":"2026-07-04T16:12:02.974746+00:00"},{"alias_kind":"pith_short_12","alias_value":"D7GD4APIGYBV","created_at":"2026-07-04T16:12:02.974746+00:00"},{"alias_kind":"pith_short_16","alias_value":"D7GD4APIGYBV74GS","created_at":"2026-07-04T16:12:02.974746+00:00"},{"alias_kind":"pith_short_8","alias_value":"D7GD4API","created_at":"2026-07-04T16:12:02.974746+00:00"}],"events":[],"event_summary":{},"paper_claims":[],"inbound_citations":{"count":1,"internal_anchor_count":1,"sample":[{"citing_arxiv_id":"2506.11188","citing_title":"Patchy Helium and Hydrogen Reionization from the Kinetic Sunyaev-Zel'dovich Effect and Galaxies","ref_index":78,"is_internal_anchor":true}]},"formal_canon":{"evidence_count":0,"sample":[],"anchors":[]},"links":{"html":"https://pith.science/pith/D7GD4APIGYBV74GSKWQNB2GUO7","json":"https://pith.science/pith/D7GD4APIGYBV74GSKWQNB2GUO7.json","graph_json":"https://pith.science/api/pith-number/D7GD4APIGYBV74GSKWQNB2GUO7/graph.json","events_json":"https://pith.science/api/pith-number/D7GD4APIGYBV74GSKWQNB2GUO7/events.json","paper":"https://pith.science/paper/D7GD4API"},"agent_actions":{"view_html":"https://pith.science/pith/D7GD4APIGYBV74GSKWQNB2GUO7","download_json":"https://pith.science/pith/D7GD4APIGYBV74GSKWQNB2GUO7.json","view_paper":"https://pith.science/paper/D7GD4API","resolve_alias":"https://pith.science/api/pith-number/resolve?arxiv=astro-ph/9912432&json=true","fetch_graph":"https://pith.science/api/pith-number/D7GD4APIGYBV74GSKWQNB2GUO7/graph.json","fetch_events":"https://pith.science/api/pith-number/D7GD4APIGYBV74GSKWQNB2GUO7/events.json","actions":{"anchor_timestamp":"https://pith.science/pith/D7GD4APIGYBV74GSKWQNB2GUO7/action/timestamp_anchor","attest_storage":"https://pith.science/pith/D7GD4APIGYBV74GSKWQNB2GUO7/action/storage_attestation","attest_author":"https://pith.science/pith/D7GD4APIGYBV74GSKWQNB2GUO7/action/author_attestation","sign_citation":"https://pith.science/pith/D7GD4APIGYBV74GSKWQNB2GUO7/action/citation_signature","submit_replication":"https://pith.science/pith/D7GD4APIGYBV74GSKWQNB2GUO7/action/replication_record"}},"created_at":"2026-07-04T16:12:02.974746+00:00","updated_at":"2026-07-04T16:12:02.974746+00:00"}