{"record_type":"pith_number_record","schema_url":"https://pith.science/schemas/pith-number/v1.json","pith_number":"pith:2025:RKFD57F3ZEZ35HPLOSGVTAVXGM","short_pith_number":"pith:RKFD57F3","schema_version":"1.0","canonical_sha256":"8a8a3efcbbc933be9deb748d5982b7333629dda7d2e8817b8232e711653382f6","source":{"kind":"arxiv","id":"2502.05261","version":2},"attestation_state":"computed","paper":{"title":"The Qz5 Survey (I): How the HI Mass Density of the Universe Evolves With Cosmic Time","license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","headline":"","cross_cats":["astro-ph.CO"],"primary_cat":"astro-ph.GA","authors_text":"Fiona Ozyurt, George D. Becker, Grecco A. Oyarz\\'un, G. Worseck, J. Xavier Prochaska, Lise Christensen, Marcel Neeleman, Marc Rafelski, M.E. Wisz, Michele Fumagalli, Regina A. Jorgenson, Sebasti\\'an L\\'opez","submitted_at":"2025-02-07T19:00:01Z","abstract_excerpt":"We report that the neutral hydrogen (HI) mass density of the Universe ($\\rho_{HI}$) increases with cosmic time since $z \\sim 5$, peaks at $z \\sim 3$, and then decreases toward $z \\sim 0$. This is the first result of Qz5, our spectroscopic survey of 63 quasars at $z \\gtrsim 5$ with VLT/X-SHOOTER and Keck/ESI aimed at characterizing intervening HI gas absorbers at $z \\sim 5$. The main feature of Qz5 is the high resolution ($R \\sim 7000 - 9000$) of the spectra, which allows us to (1) accurately detect high column density HI gas absorbers in an increasingly neutral intergalactic medium at $z \\sim "},"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":"2502.05261","kind":"arxiv","version":2},"metadata":{"license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","primary_cat":"astro-ph.GA","submitted_at":"2025-02-07T19:00:01Z","cross_cats_sorted":["astro-ph.CO"],"title_canon_sha256":"532ccb28f7f713c54ba4c49af6cf27e9bb67637380e66d153136ade877facf36","abstract_canon_sha256":"607f618c92cb502a0ca01de58672c0ad7b5d9189ae4d2d9bfdbeb18df6dbfb61"},"schema_version":"1.0"},"receipt":{"kind":"pith_receipt","key_id":"pith-v1-2026-05","algorithm":"ed25519","signed_at":"2026-07-05T10:36:35.780488Z","signature_b64":"CqWZW9ihVD03pcPxf3ZrmjJCIexS3DStJ+nCOUJop5dkvc9Fa00Bt2syD7uJcTVOfhvsu7SLmw10k4LRhEGeDg==","signed_message":"canonical_sha256_bytes","builder_version":"pith-number-builder-2026-05-17-v1","receipt_version":"0.3","canonical_sha256":"8a8a3efcbbc933be9deb748d5982b7333629dda7d2e8817b8232e711653382f6","last_reissued_at":"2026-07-05T10:36:35.779653Z","signature_status":"signed_v1","first_computed_at":"2026-07-05T10:36:35.779653Z","public_key_fingerprint":"8d4b5ee74e4693bcd1df2446408b0d54"},"graph_snapshot":{"paper":{"title":"The Qz5 Survey (I): How the HI Mass Density of the Universe Evolves With Cosmic Time","license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","headline":"","cross_cats":["astro-ph.CO"],"primary_cat":"astro-ph.GA","authors_text":"Fiona Ozyurt, George D. Becker, Grecco A. Oyarz\\'un, G. Worseck, J. Xavier Prochaska, Lise Christensen, Marcel Neeleman, Marc Rafelski, M.E. Wisz, Michele Fumagalli, Regina A. Jorgenson, Sebasti\\'an L\\'opez","submitted_at":"2025-02-07T19:00:01Z","abstract_excerpt":"We report that the neutral hydrogen (HI) mass density of the Universe ($\\rho_{HI}$) increases with cosmic time since $z \\sim 5$, peaks at $z \\sim 3$, and then decreases toward $z \\sim 0$. This is the first result of Qz5, our spectroscopic survey of 63 quasars at $z \\gtrsim 5$ with VLT/X-SHOOTER and Keck/ESI aimed at characterizing intervening HI gas absorbers at $z \\sim 5$. The main feature of Qz5 is the high resolution ($R \\sim 7000 - 9000$) of the spectra, which allows us to (1) accurately detect high column density HI gas absorbers in an increasingly neutral intergalactic medium at $z \\sim "},"claims":{"count":0,"items":[],"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"source":{"id":"2502.05261","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/2502.05261/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":"2502.05261","created_at":"2026-07-05T10:36:35.779796+00:00"},{"alias_kind":"arxiv_version","alias_value":"2502.05261v2","created_at":"2026-07-05T10:36:35.779796+00:00"},{"alias_kind":"doi","alias_value":"10.48550/arxiv.2502.05261","created_at":"2026-07-05T10:36:35.779796+00:00"},{"alias_kind":"pith_short_12","alias_value":"RKFD57F3ZEZ3","created_at":"2026-07-05T10:36:35.779796+00:00"},{"alias_kind":"pith_short_16","alias_value":"RKFD57F3ZEZ35HPL","created_at":"2026-07-05T10:36:35.779796+00:00"},{"alias_kind":"pith_short_8","alias_value":"RKFD57F3","created_at":"2026-07-05T10:36:35.779796+00:00"}],"events":[],"event_summary":{},"paper_claims":[],"inbound_citations":{"count":1,"internal_anchor_count":1,"sample":[{"citing_arxiv_id":"2607.05087","citing_title":"Lyman-alpha haloes in the aftermath of reionisation","ref_index":66,"is_internal_anchor":true}]},"formal_canon":{"evidence_count":0,"sample":[],"anchors":[]},"links":{"html":"https://pith.science/pith/RKFD57F3ZEZ35HPLOSGVTAVXGM","json":"https://pith.science/pith/RKFD57F3ZEZ35HPLOSGVTAVXGM.json","graph_json":"https://pith.science/api/pith-number/RKFD57F3ZEZ35HPLOSGVTAVXGM/graph.json","events_json":"https://pith.science/api/pith-number/RKFD57F3ZEZ35HPLOSGVTAVXGM/events.json","paper":"https://pith.science/paper/RKFD57F3"},"agent_actions":{"view_html":"https://pith.science/pith/RKFD57F3ZEZ35HPLOSGVTAVXGM","download_json":"https://pith.science/pith/RKFD57F3ZEZ35HPLOSGVTAVXGM.json","view_paper":"https://pith.science/paper/RKFD57F3","resolve_alias":"https://pith.science/api/pith-number/resolve?arxiv=2502.05261&json=true","fetch_graph":"https://pith.science/api/pith-number/RKFD57F3ZEZ35HPLOSGVTAVXGM/graph.json","fetch_events":"https://pith.science/api/pith-number/RKFD57F3ZEZ35HPLOSGVTAVXGM/events.json","actions":{"anchor_timestamp":"https://pith.science/pith/RKFD57F3ZEZ35HPLOSGVTAVXGM/action/timestamp_anchor","attest_storage":"https://pith.science/pith/RKFD57F3ZEZ35HPLOSGVTAVXGM/action/storage_attestation","attest_author":"https://pith.science/pith/RKFD57F3ZEZ35HPLOSGVTAVXGM/action/author_attestation","sign_citation":"https://pith.science/pith/RKFD57F3ZEZ35HPLOSGVTAVXGM/action/citation_signature","submit_replication":"https://pith.science/pith/RKFD57F3ZEZ35HPLOSGVTAVXGM/action/replication_record"}},"created_at":"2026-07-05T10:36:35.779796+00:00","updated_at":"2026-07-05T10:36:35.779796+00:00"}