{"record_type":"pith_number_record","schema_url":"https://pith.science/schemas/pith-number/v1.json","pith_number":"pith:2022:SIQK5QFNONDSBKLDS7BPPTOPHY","short_pith_number":"pith:SIQK5QFN","schema_version":"1.0","canonical_sha256":"9220aec0ad734720a96397c2f7cdcf3e2863b56e02e408bc5a109c1fa93e2ea5","source":{"kind":"arxiv","id":"2206.02947","version":1},"attestation_state":"computed","paper":{"title":"Discovery of three new near-pristine absorption clouds at $z=2.6$-4.4","license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","headline":"","cross_cats":["astro-ph.GA"],"primary_cat":"astro-ph.CO","authors_text":"(2) Saint Michael's College, 3), (3) W. M. Keck Observatory, (4) Durham University, 5, (5) University of Milan, 6) ((1) Swinburne University of Technology, (6) Astronomical Observatory of Trieste), John M. O'Meara (2, Michael T. Murphy (1), Michele Fumagalli (4, Neil H. M. Crighton (1), P. Fr\\'ed\\'eric Robert (1)","submitted_at":"2022-06-06T23:24:33Z","abstract_excerpt":"We report the discovery of three new \"near-pristine\" Lyman Limit Systems (LLSs), with metallicities ~1/1000 solar, at redshifts 2.6, 3.8 and 4.0, with a targeted survey at the Keck Observatory. High resolution echelle spectra of eight candidates yielded precise column densities of hydrogen and weak, but clearly detected, metal lines in seven LLSs; we previously reported the one remaining, apparently metal-free LLS, to have metallicity <1/10000 solar. Robust photoionisation modelling provides metallicities [Si/H] = -3.05 to -2.94, with 0.26 dex uncertainties (95% confidence) for three LLSs, and"},"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":"2206.02947","kind":"arxiv","version":1},"metadata":{"license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","primary_cat":"astro-ph.CO","submitted_at":"2022-06-06T23:24:33Z","cross_cats_sorted":["astro-ph.GA"],"title_canon_sha256":"661b057da3d4b8c6568a3e60fa1b6ca43375d53aae3f532a32efbdc613c408d0","abstract_canon_sha256":"2e5625d5493d6d2d5bc2335e7ea37e69a66f933f115584155feb59b0a17bbd68"},"schema_version":"1.0"},"receipt":{"kind":"pith_receipt","key_id":"pith-v1-2026-05","algorithm":"ed25519","signed_at":"2026-07-05T04:45:22.478201Z","signature_b64":"MPVHynRqdlcvEfmhdWtYgK1un0u5jDhR6161CH11LnphTkUHKI9HTmPlW/l3JEC7bkZsdhuh2zB7D8YaEFFTCw==","signed_message":"canonical_sha256_bytes","builder_version":"pith-number-builder-2026-05-17-v1","receipt_version":"0.3","canonical_sha256":"9220aec0ad734720a96397c2f7cdcf3e2863b56e02e408bc5a109c1fa93e2ea5","last_reissued_at":"2026-07-05T04:45:22.477697Z","signature_status":"signed_v1","first_computed_at":"2026-07-05T04:45:22.477697Z","public_key_fingerprint":"8d4b5ee74e4693bcd1df2446408b0d54"},"graph_snapshot":{"paper":{"title":"Discovery of three new near-pristine absorption clouds at $z=2.6$-4.4","license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","headline":"","cross_cats":["astro-ph.GA"],"primary_cat":"astro-ph.CO","authors_text":"(2) Saint Michael's College, 3), (3) W. M. Keck Observatory, (4) Durham University, 5, (5) University of Milan, 6) ((1) Swinburne University of Technology, (6) Astronomical Observatory of Trieste), John M. O'Meara (2, Michael T. Murphy (1), Michele Fumagalli (4, Neil H. M. Crighton (1), P. Fr\\'ed\\'eric Robert (1)","submitted_at":"2022-06-06T23:24:33Z","abstract_excerpt":"We report the discovery of three new \"near-pristine\" Lyman Limit Systems (LLSs), with metallicities ~1/1000 solar, at redshifts 2.6, 3.8 and 4.0, with a targeted survey at the Keck Observatory. High resolution echelle spectra of eight candidates yielded precise column densities of hydrogen and weak, but clearly detected, metal lines in seven LLSs; we previously reported the one remaining, apparently metal-free LLS, to have metallicity <1/10000 solar. Robust photoionisation modelling provides metallicities [Si/H] = -3.05 to -2.94, with 0.26 dex uncertainties (95% confidence) for three LLSs, and"},"claims":{"count":0,"items":[],"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"source":{"id":"2206.02947","kind":"arxiv","version":1},"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/2206.02947/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":"2206.02947","created_at":"2026-07-05T04:45:22.477755+00:00"},{"alias_kind":"arxiv_version","alias_value":"2206.02947v1","created_at":"2026-07-05T04:45:22.477755+00:00"},{"alias_kind":"doi","alias_value":"10.48550/arxiv.2206.02947","created_at":"2026-07-05T04:45:22.477755+00:00"},{"alias_kind":"pith_short_12","alias_value":"SIQK5QFNONDS","created_at":"2026-07-05T04:45:22.477755+00:00"},{"alias_kind":"pith_short_16","alias_value":"SIQK5QFNONDSBKLD","created_at":"2026-07-05T04:45:22.477755+00:00"},{"alias_kind":"pith_short_8","alias_value":"SIQK5QFN","created_at":"2026-07-05T04:45:22.477755+00:00"}],"events":[],"event_summary":{},"paper_claims":[],"inbound_citations":{"count":0,"internal_anchor_count":0,"sample":[]},"formal_canon":{"evidence_count":0,"sample":[],"anchors":[]},"links":{"html":"https://pith.science/pith/SIQK5QFNONDSBKLDS7BPPTOPHY","json":"https://pith.science/pith/SIQK5QFNONDSBKLDS7BPPTOPHY.json","graph_json":"https://pith.science/api/pith-number/SIQK5QFNONDSBKLDS7BPPTOPHY/graph.json","events_json":"https://pith.science/api/pith-number/SIQK5QFNONDSBKLDS7BPPTOPHY/events.json","paper":"https://pith.science/paper/SIQK5QFN"},"agent_actions":{"view_html":"https://pith.science/pith/SIQK5QFNONDSBKLDS7BPPTOPHY","download_json":"https://pith.science/pith/SIQK5QFNONDSBKLDS7BPPTOPHY.json","view_paper":"https://pith.science/paper/SIQK5QFN","resolve_alias":"https://pith.science/api/pith-number/resolve?arxiv=2206.02947&json=true","fetch_graph":"https://pith.science/api/pith-number/SIQK5QFNONDSBKLDS7BPPTOPHY/graph.json","fetch_events":"https://pith.science/api/pith-number/SIQK5QFNONDSBKLDS7BPPTOPHY/events.json","actions":{"anchor_timestamp":"https://pith.science/pith/SIQK5QFNONDSBKLDS7BPPTOPHY/action/timestamp_anchor","attest_storage":"https://pith.science/pith/SIQK5QFNONDSBKLDS7BPPTOPHY/action/storage_attestation","attest_author":"https://pith.science/pith/SIQK5QFNONDSBKLDS7BPPTOPHY/action/author_attestation","sign_citation":"https://pith.science/pith/SIQK5QFNONDSBKLDS7BPPTOPHY/action/citation_signature","submit_replication":"https://pith.science/pith/SIQK5QFNONDSBKLDS7BPPTOPHY/action/replication_record"}},"created_at":"2026-07-05T04:45:22.477755+00:00","updated_at":"2026-07-05T04:45:22.477755+00:00"}