{"record_type":"pith_number_record","schema_url":"https://pith.science/schemas/pith-number/v1.json","pith_number":"pith:2023:6K4WPHHQ65TKPUORJJSQ7WYBJB","short_pith_number":"pith:6K4WPHHQ","schema_version":"1.0","canonical_sha256":"f2b9679cf0f766a7d1d14a650fdb01484a58d2f238b9f0c2a9139497e3e93833","source":{"kind":"arxiv","id":"2302.14738","version":1},"attestation_state":"computed","paper":{"title":"H$_2$O MegaMaser emission in NGC 4258 indicative of a periodic disc instability","license":"http://creativecommons.org/licenses/by-nc-sa/4.0/","headline":"","cross_cats":[],"primary_cat":"astro-ph.GA","authors_text":"Andrej Sobolev, Christian Henkel, Hiroshi Imai, Tao An, Vladimir Kostenko, Wiillem A. Baan","submitted_at":"2023-02-28T16:41:12Z","abstract_excerpt":"H$_2$O MegaMaser emission may arise from thin gas discs surrounding the massive nuclei of galaxies such as NGC\\,4258, but the physical conditions responsible for the amplified emission are unclear. A detailed view of these regions is possible using the very high angular resolution afforded by space very long baseline interferometry (SVLBI). Here we report SVLBI experiments conducted using the orbiting RadioAstron Observatory that have resulted in detections of the H$_2$O 22 GHz emission in NGC\\,4258, with Earth-space baselines of 1.3, 9.5 and 19.5 Earth diameters. Observations at the highest a"},"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":"2302.14738","kind":"arxiv","version":1},"metadata":{"license":"http://creativecommons.org/licenses/by-nc-sa/4.0/","primary_cat":"astro-ph.GA","submitted_at":"2023-02-28T16:41:12Z","cross_cats_sorted":[],"title_canon_sha256":"579f9cff709cab8f6c23e07efa39a07701142ff2601a7b3443b3448c6c11edc4","abstract_canon_sha256":"352137d20dcd639918f2e74c7ac2ee8fc9398eae39622e4d031f3aeb9ab31a21"},"schema_version":"1.0"},"receipt":{"kind":"pith_receipt","key_id":"pith-v1-2026-05","algorithm":"ed25519","signed_at":"2026-07-05T05:46:49.204803Z","signature_b64":"sP37a/k4eHtXjt/Umbeh9KISM6hgFpNu18k9a9QPbQ2Y/eBkigmE8QtEPStwvWmiL/4EibIS/hP+y5TDWwHVAQ==","signed_message":"canonical_sha256_bytes","builder_version":"pith-number-builder-2026-05-17-v1","receipt_version":"0.3","canonical_sha256":"f2b9679cf0f766a7d1d14a650fdb01484a58d2f238b9f0c2a9139497e3e93833","last_reissued_at":"2026-07-05T05:46:49.204414Z","signature_status":"signed_v1","first_computed_at":"2026-07-05T05:46:49.204414Z","public_key_fingerprint":"8d4b5ee74e4693bcd1df2446408b0d54"},"graph_snapshot":{"paper":{"title":"H$_2$O MegaMaser emission in NGC 4258 indicative of a periodic disc instability","license":"http://creativecommons.org/licenses/by-nc-sa/4.0/","headline":"","cross_cats":[],"primary_cat":"astro-ph.GA","authors_text":"Andrej Sobolev, Christian Henkel, Hiroshi Imai, Tao An, Vladimir Kostenko, Wiillem A. Baan","submitted_at":"2023-02-28T16:41:12Z","abstract_excerpt":"H$_2$O MegaMaser emission may arise from thin gas discs surrounding the massive nuclei of galaxies such as NGC\\,4258, but the physical conditions responsible for the amplified emission are unclear. A detailed view of these regions is possible using the very high angular resolution afforded by space very long baseline interferometry (SVLBI). Here we report SVLBI experiments conducted using the orbiting RadioAstron Observatory that have resulted in detections of the H$_2$O 22 GHz emission in NGC\\,4258, with Earth-space baselines of 1.3, 9.5 and 19.5 Earth diameters. Observations at the highest a"},"claims":{"count":0,"items":[],"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"source":{"id":"2302.14738","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/2302.14738/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":"2302.14738","created_at":"2026-07-05T05:46:49.204470+00:00"},{"alias_kind":"arxiv_version","alias_value":"2302.14738v1","created_at":"2026-07-05T05:46:49.204470+00:00"},{"alias_kind":"doi","alias_value":"10.48550/arxiv.2302.14738","created_at":"2026-07-05T05:46:49.204470+00:00"},{"alias_kind":"pith_short_12","alias_value":"6K4WPHHQ65TK","created_at":"2026-07-05T05:46:49.204470+00:00"},{"alias_kind":"pith_short_16","alias_value":"6K4WPHHQ65TKPUOR","created_at":"2026-07-05T05:46:49.204470+00:00"},{"alias_kind":"pith_short_8","alias_value":"6K4WPHHQ","created_at":"2026-07-05T05:46:49.204470+00:00"}],"events":[],"event_summary":{},"paper_claims":[],"inbound_citations":{"count":1,"internal_anchor_count":1,"sample":[{"citing_arxiv_id":"2608.09657","citing_title":"Wigner interferometry","ref_index":11,"is_internal_anchor":true}]},"formal_canon":{"evidence_count":0,"sample":[],"anchors":[]},"links":{"html":"https://pith.science/pith/6K4WPHHQ65TKPUORJJSQ7WYBJB","json":"https://pith.science/pith/6K4WPHHQ65TKPUORJJSQ7WYBJB.json","graph_json":"https://pith.science/api/pith-number/6K4WPHHQ65TKPUORJJSQ7WYBJB/graph.json","events_json":"https://pith.science/api/pith-number/6K4WPHHQ65TKPUORJJSQ7WYBJB/events.json","paper":"https://pith.science/paper/6K4WPHHQ"},"agent_actions":{"view_html":"https://pith.science/pith/6K4WPHHQ65TKPUORJJSQ7WYBJB","download_json":"https://pith.science/pith/6K4WPHHQ65TKPUORJJSQ7WYBJB.json","view_paper":"https://pith.science/paper/6K4WPHHQ","resolve_alias":"https://pith.science/api/pith-number/resolve?arxiv=2302.14738&json=true","fetch_graph":"https://pith.science/api/pith-number/6K4WPHHQ65TKPUORJJSQ7WYBJB/graph.json","fetch_events":"https://pith.science/api/pith-number/6K4WPHHQ65TKPUORJJSQ7WYBJB/events.json","actions":{"anchor_timestamp":"https://pith.science/pith/6K4WPHHQ65TKPUORJJSQ7WYBJB/action/timestamp_anchor","attest_storage":"https://pith.science/pith/6K4WPHHQ65TKPUORJJSQ7WYBJB/action/storage_attestation","attest_author":"https://pith.science/pith/6K4WPHHQ65TKPUORJJSQ7WYBJB/action/author_attestation","sign_citation":"https://pith.science/pith/6K4WPHHQ65TKPUORJJSQ7WYBJB/action/citation_signature","submit_replication":"https://pith.science/pith/6K4WPHHQ65TKPUORJJSQ7WYBJB/action/replication_record"}},"created_at":"2026-07-05T05:46:49.204470+00:00","updated_at":"2026-07-05T05:46:49.204470+00:00"}