{"record_type":"pith_number_record","schema_url":"https://pith.science/schemas/pith-number/v1.json","pith_number":"pith:2016:AEWCKPPJY3JS32XRVPEJJCPGKE","short_pith_number":"pith:AEWCKPPJ","schema_version":"1.0","canonical_sha256":"012c253de9c6d32deaf1abc89489e651372ba297bc1a41940aef0d8ac8f9e7f0","source":{"kind":"arxiv","id":"1609.08748","version":2},"attestation_state":"computed","paper":{"title":"Measuring the speed of light with ultra-compact radio quasars","license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","headline":"","cross_cats":[],"primary_cat":"astro-ph.CO","authors_text":"John Jackson, Marek Biesiada, Shuo Cao, Xiaogang Zheng, Yuhang Zhao, Zong-Hong Zhu","submitted_at":"2016-09-28T03:17:56Z","abstract_excerpt":"In this paper, based on a 2.29 GHz VLBI all-sky survey of 613 milliarcsecond ultra-compact radio sources with $0.0035<z<3.787$, we describe a method of identifying the sub-sample which can serve as individual standard rulers in cosmology. If the linear size of the compact structure is assumed to depend on source luminosity and redshift as $l_m=l L^\\beta (1+z)^n$, only intermediate-luminosity quasars ($10^{27}$ W/Hz$<L<$ $10^{28}$ W/Hz) show negligible dependence ($|n|\\simeq 10^{-3}$, $|\\beta|\\simeq 10^{-4}$), and thus represent a population of such rulers with fixed characteristic length $l=11"},"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":"1609.08748","kind":"arxiv","version":2},"metadata":{"license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","primary_cat":"astro-ph.CO","submitted_at":"2016-09-28T03:17:56Z","cross_cats_sorted":[],"title_canon_sha256":"858f302f7cc2a77134a4ad117b6f93f431a4dc67238a6c65fc6a95067139d484","abstract_canon_sha256":"4931018fce13f615af55ec335096053454145bf55836d18324daeea4cfc9a807"},"schema_version":"1.0"},"receipt":{"kind":"pith_receipt","key_id":"pith-v1-2026-05","algorithm":"ed25519","signed_at":"2026-05-18T00:26:46.820837Z","signature_b64":"HoY/yYjgPJjd95Bnav0iRDBpVjpeWS0AL1UyyIIWhLX+W5cICGVLkFeoQ1mc89mwQF7y9zzXGY/3zV2EWZzCAw==","signed_message":"canonical_sha256_bytes","builder_version":"pith-number-builder-2026-05-17-v1","receipt_version":"0.3","canonical_sha256":"012c253de9c6d32deaf1abc89489e651372ba297bc1a41940aef0d8ac8f9e7f0","last_reissued_at":"2026-05-18T00:26:46.820293Z","signature_status":"signed_v1","first_computed_at":"2026-05-18T00:26:46.820293Z","public_key_fingerprint":"8d4b5ee74e4693bcd1df2446408b0d54"},"graph_snapshot":{"paper":{"title":"Measuring the speed of light with ultra-compact radio quasars","license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","headline":"","cross_cats":[],"primary_cat":"astro-ph.CO","authors_text":"John Jackson, Marek Biesiada, Shuo Cao, Xiaogang Zheng, Yuhang Zhao, Zong-Hong Zhu","submitted_at":"2016-09-28T03:17:56Z","abstract_excerpt":"In this paper, based on a 2.29 GHz VLBI all-sky survey of 613 milliarcsecond ultra-compact radio sources with $0.0035<z<3.787$, we describe a method of identifying the sub-sample which can serve as individual standard rulers in cosmology. If the linear size of the compact structure is assumed to depend on source luminosity and redshift as $l_m=l L^\\beta (1+z)^n$, only intermediate-luminosity quasars ($10^{27}$ W/Hz$<L<$ $10^{28}$ W/Hz) show negligible dependence ($|n|\\simeq 10^{-3}$, $|\\beta|\\simeq 10^{-4}$), and thus represent a population of such rulers with fixed characteristic length $l=11"},"claims":{"count":0,"items":[],"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"source":{"id":"1609.08748","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":""},"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":"1609.08748","created_at":"2026-05-18T00:26:46.820404+00:00"},{"alias_kind":"arxiv_version","alias_value":"1609.08748v2","created_at":"2026-05-18T00:26:46.820404+00:00"},{"alias_kind":"doi","alias_value":"10.48550/arxiv.1609.08748","created_at":"2026-05-18T00:26:46.820404+00:00"},{"alias_kind":"pith_short_12","alias_value":"AEWCKPPJY3JS","created_at":"2026-05-18T12:30:07.202191+00:00"},{"alias_kind":"pith_short_16","alias_value":"AEWCKPPJY3JS32XR","created_at":"2026-05-18T12:30:07.202191+00:00"},{"alias_kind":"pith_short_8","alias_value":"AEWCKPPJ","created_at":"2026-05-18T12:30:07.202191+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/AEWCKPPJY3JS32XRVPEJJCPGKE","json":"https://pith.science/pith/AEWCKPPJY3JS32XRVPEJJCPGKE.json","graph_json":"https://pith.science/api/pith-number/AEWCKPPJY3JS32XRVPEJJCPGKE/graph.json","events_json":"https://pith.science/api/pith-number/AEWCKPPJY3JS32XRVPEJJCPGKE/events.json","paper":"https://pith.science/paper/AEWCKPPJ"},"agent_actions":{"view_html":"https://pith.science/pith/AEWCKPPJY3JS32XRVPEJJCPGKE","download_json":"https://pith.science/pith/AEWCKPPJY3JS32XRVPEJJCPGKE.json","view_paper":"https://pith.science/paper/AEWCKPPJ","resolve_alias":"https://pith.science/api/pith-number/resolve?arxiv=1609.08748&json=true","fetch_graph":"https://pith.science/api/pith-number/AEWCKPPJY3JS32XRVPEJJCPGKE/graph.json","fetch_events":"https://pith.science/api/pith-number/AEWCKPPJY3JS32XRVPEJJCPGKE/events.json","actions":{"anchor_timestamp":"https://pith.science/pith/AEWCKPPJY3JS32XRVPEJJCPGKE/action/timestamp_anchor","attest_storage":"https://pith.science/pith/AEWCKPPJY3JS32XRVPEJJCPGKE/action/storage_attestation","attest_author":"https://pith.science/pith/AEWCKPPJY3JS32XRVPEJJCPGKE/action/author_attestation","sign_citation":"https://pith.science/pith/AEWCKPPJY3JS32XRVPEJJCPGKE/action/citation_signature","submit_replication":"https://pith.science/pith/AEWCKPPJY3JS32XRVPEJJCPGKE/action/replication_record"}},"created_at":"2026-05-18T00:26:46.820404+00:00","updated_at":"2026-05-18T00:26:46.820404+00:00"}