{"record_type":"pith_number_record","schema_url":"https://pith.science/schemas/pith-number/v1.json","pith_number":"pith:2012:4DSPHWRVWOVADN6SCQFIE4TG4V","short_pith_number":"pith:4DSPHWRV","schema_version":"1.0","canonical_sha256":"e0e4f3da35b3aa01b7d2140a827266e56622b201c9a564f076ea2543d329f2c0","source":{"kind":"arxiv","id":"1209.3989","version":1},"attestation_state":"computed","paper":{"title":"The Impact of Frequency Standards on Coherence in VLBI at the Highest Frequencies","license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","headline":"","cross_cats":[],"primary_cat":"astro-ph.IM","authors_text":"J. Hartnett, M. Rioja, R. Dodson, S. Tingay, Y. Asaki","submitted_at":"2012-09-18T15:25:26Z","abstract_excerpt":"We have carried out full imaging simulation studies to explore the impact of frequency standards in millimeter and sub-millimeter Very Long Baseline Interferometry (VLBI), focusing on the coherence time and sensitivity. In particular, we compare the performance of the H-maser, traditionally used in VLBI, to that of ultra-stable cryocooled sapphire oscillators over a range of observing frequencies, weather conditions and analysis strategies. Our simulations show that at the highest frequencies, the losses induced by H-maser instabilities are comparable to those from high quality tropospheric co"},"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":"1209.3989","kind":"arxiv","version":1},"metadata":{"license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","primary_cat":"astro-ph.IM","submitted_at":"2012-09-18T15:25:26Z","cross_cats_sorted":[],"title_canon_sha256":"9dc15b68483995e924322d2a4e7f6baa6f64a2eab38152deb2427532c8806292","abstract_canon_sha256":"6332932f53d758f3e32087c3ff06b0f37a41de746408b74e20734c5b06ca294f"},"schema_version":"1.0"},"receipt":{"kind":"pith_receipt","key_id":"pith-v1-2026-05","algorithm":"ed25519","signed_at":"2026-05-18T01:54:26.826910Z","signature_b64":"5mFKPARU82GttXqeq9aUxldKo9sSABiQ3dbPWsivKtl2nVA1/hDG8XjEveK6+UVoMIDVuPEVOIkXKmIH2eykDQ==","signed_message":"canonical_sha256_bytes","builder_version":"pith-number-builder-2026-05-17-v1","receipt_version":"0.3","canonical_sha256":"e0e4f3da35b3aa01b7d2140a827266e56622b201c9a564f076ea2543d329f2c0","last_reissued_at":"2026-05-18T01:54:26.826520Z","signature_status":"signed_v1","first_computed_at":"2026-05-18T01:54:26.826520Z","public_key_fingerprint":"8d4b5ee74e4693bcd1df2446408b0d54"},"graph_snapshot":{"paper":{"title":"The Impact of Frequency Standards on Coherence in VLBI at the Highest Frequencies","license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","headline":"","cross_cats":[],"primary_cat":"astro-ph.IM","authors_text":"J. Hartnett, M. Rioja, R. Dodson, S. Tingay, Y. Asaki","submitted_at":"2012-09-18T15:25:26Z","abstract_excerpt":"We have carried out full imaging simulation studies to explore the impact of frequency standards in millimeter and sub-millimeter Very Long Baseline Interferometry (VLBI), focusing on the coherence time and sensitivity. In particular, we compare the performance of the H-maser, traditionally used in VLBI, to that of ultra-stable cryocooled sapphire oscillators over a range of observing frequencies, weather conditions and analysis strategies. Our simulations show that at the highest frequencies, the losses induced by H-maser instabilities are comparable to those from high quality tropospheric co"},"claims":{"count":0,"items":[],"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"source":{"id":"1209.3989","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":""},"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":"1209.3989","created_at":"2026-05-18T01:54:26.826580+00:00"},{"alias_kind":"arxiv_version","alias_value":"1209.3989v1","created_at":"2026-05-18T01:54:26.826580+00:00"},{"alias_kind":"doi","alias_value":"10.48550/arxiv.1209.3989","created_at":"2026-05-18T01:54:26.826580+00:00"},{"alias_kind":"pith_short_12","alias_value":"4DSPHWRVWOVA","created_at":"2026-05-18T12:26:53.410803+00:00"},{"alias_kind":"pith_short_16","alias_value":"4DSPHWRVWOVADN6S","created_at":"2026-05-18T12:26:53.410803+00:00"},{"alias_kind":"pith_short_8","alias_value":"4DSPHWRV","created_at":"2026-05-18T12:26:53.410803+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/4DSPHWRVWOVADN6SCQFIE4TG4V","json":"https://pith.science/pith/4DSPHWRVWOVADN6SCQFIE4TG4V.json","graph_json":"https://pith.science/api/pith-number/4DSPHWRVWOVADN6SCQFIE4TG4V/graph.json","events_json":"https://pith.science/api/pith-number/4DSPHWRVWOVADN6SCQFIE4TG4V/events.json","paper":"https://pith.science/paper/4DSPHWRV"},"agent_actions":{"view_html":"https://pith.science/pith/4DSPHWRVWOVADN6SCQFIE4TG4V","download_json":"https://pith.science/pith/4DSPHWRVWOVADN6SCQFIE4TG4V.json","view_paper":"https://pith.science/paper/4DSPHWRV","resolve_alias":"https://pith.science/api/pith-number/resolve?arxiv=1209.3989&json=true","fetch_graph":"https://pith.science/api/pith-number/4DSPHWRVWOVADN6SCQFIE4TG4V/graph.json","fetch_events":"https://pith.science/api/pith-number/4DSPHWRVWOVADN6SCQFIE4TG4V/events.json","actions":{"anchor_timestamp":"https://pith.science/pith/4DSPHWRVWOVADN6SCQFIE4TG4V/action/timestamp_anchor","attest_storage":"https://pith.science/pith/4DSPHWRVWOVADN6SCQFIE4TG4V/action/storage_attestation","attest_author":"https://pith.science/pith/4DSPHWRVWOVADN6SCQFIE4TG4V/action/author_attestation","sign_citation":"https://pith.science/pith/4DSPHWRVWOVADN6SCQFIE4TG4V/action/citation_signature","submit_replication":"https://pith.science/pith/4DSPHWRVWOVADN6SCQFIE4TG4V/action/replication_record"}},"created_at":"2026-05-18T01:54:26.826580+00:00","updated_at":"2026-05-18T01:54:26.826580+00:00"}