{"state_type":"pith_open_graph_state","state_version":"1.0","pith_number":"pith:2024:M3QDF2RTWVSZO6BRYRVJNENGZF","merge_version":"pith-open-graph-merge-v1","event_count":2,"valid_event_count":2,"invalid_event_count":0,"equivocation_count":0,"current":{"canonical_record":{"metadata":{"abstract_canon_sha256":"5543825bdda8e559387817bf05946583a360cf3fd8002493500605d7d3ce8596","cross_cats_sorted":[],"license":"http://creativecommons.org/licenses/by/4.0/","primary_cat":"astro-ph.HE","submitted_at":"2024-07-12T19:05:24Z","title_canon_sha256":"e33a0f6d28c07df3c8f3c6d1622ef05dd2109d4f74646f7eea5f01720662b47a"},"schema_version":"1.0","source":{"id":"2407.09647","kind":"arxiv","version":2}},"source_aliases":[{"alias_kind":"arxiv","alias_value":"2407.09647","created_at":"2026-07-05T10:47:54Z"},{"alias_kind":"arxiv_version","alias_value":"2407.09647v2","created_at":"2026-07-05T10:47:54Z"},{"alias_kind":"doi","alias_value":"10.48550/arxiv.2407.09647","created_at":"2026-07-05T10:47:54Z"},{"alias_kind":"pith_short_12","alias_value":"M3QDF2RTWVSZ","created_at":"2026-07-05T10:47:54Z"},{"alias_kind":"pith_short_16","alias_value":"M3QDF2RTWVSZO6BR","created_at":"2026-07-05T10:47:54Z"},{"alias_kind":"pith_short_8","alias_value":"M3QDF2RT","created_at":"2026-07-05T10:47:54Z"}],"graph_snapshots":[{"event_id":"sha256:bfcb78501bf17a64027c789df3a6fbc6273c0e304e0f3ad13bd131a95d95e7be","target":"graph","created_at":"2026-07-05T10:47:54Z","signer":{"key_id":"pith-v1-2026-05","public_key_fingerprint":"8d4b5ee74e4693bcd1df2446408b0d54","signer_id":"pith.science","signer_type":"pith_registry"},"payload":{"graph_snapshot":{"author_claims":{"count":0,"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57","strong_count":0},"builder_version":"pith-number-builder-2026-05-17-v1","claims":{"count":0,"items":[],"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"formal_canon":{"evidence_count":0,"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"integrity":{"available":true,"clean":true,"detectors_run":[],"endpoint":"/pith/2407.09647/integrity.json","findings":[],"snapshot_sha256":"c28c3603d3b5d939e8dc4c7e95fa8dfce3d595e45f758748cecf8e644a296938","summary":{"advisory":0,"by_detector":{},"critical":0,"informational":0}},"paper":{"abstract_excerpt":"Haystack and Owens Valley Radio Observatory (OVRO) observations recently revealed strong, intermittent, sinusoidal total flux-density variations that maintained coherence between 1975 and 2021 in the blazar PKS 2131$-$021 ($z=1.283$). This was interpreted as possible evidence of a supermassive black hole binary (SMBHB). Extended observations through 2023 show coherence over 47.9 years, with an observed period $P_\\textrm{15 GHz}=(1739.8 \\pm 17.4)$ days}. We reject, with $p$-value = $2.09 \\times 10^{-7}$, the hypothesis that the variations are due to random fluctuations in the red noise tail of ","authors_text":"A. C. S. Readhead, A. G. Sullivan, A. Synani, B. Molina, C. P. O'Dea, C. R. Lawrence, D. C. Homan, F. Harrison, I. Liodakis, J. A. Zensus, K. Chatziioannou, K. Tassis, M. C. Begelman, M. F. Aller, M. J. Graham, M. L. Lister, M. Vallisneri, P. Mr\\'oz, P. V. de la Parra, R. A. Reeves, R. D. Blandford, R. Maiolino, S. Kiehlmann, S. K. N{\\ae}ss, S. O'Neill, S. R. Kulkarni, T. A. Prince, T. Hovatta, T. J. Pearson, T. J. W. Lazio, V. Pavlidou, V. Ravi, W. Max-Moerbeck, Y. Ding","cross_cats":[],"headline":"","license":"http://creativecommons.org/licenses/by/4.0/","primary_cat":"astro-ph.HE","submitted_at":"2024-07-12T19:05:24Z","title":"PKS 2131-021 -- Discovery of Strong Coherent Sinusoidal Variations from Radio to Optical Frequencies: Compelling Evidence for a Blazar Supermassive Black Hole Binary"},"references":{"count":0,"internal_anchors":0,"resolved_work":0,"sample":[],"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"source":{"id":"2407.09647","kind":"arxiv","version":2},"verdict":{"created_at":null,"id":null,"model_set":{},"one_line_summary":"","pipeline_version":null,"pith_extraction_headline":"","strongest_claim":"","weakest_assumption":""}},"verdict_id":null}}],"author_attestations":[],"timestamp_anchors":[],"storage_attestations":[],"citation_signatures":[],"replication_records":[],"corrections":[],"mirror_hints":[],"record_created":{"event_id":"sha256:b604b3f6413a5b3d06d6c9cbe3ce53092ab16ac88402260120412ca367c16e5b","target":"record","created_at":"2026-07-05T10:47:54Z","signer":{"key_id":"pith-v1-2026-05","public_key_fingerprint":"8d4b5ee74e4693bcd1df2446408b0d54","signer_id":"pith.science","signer_type":"pith_registry"},"payload":{"attestation_state":"computed","canonical_record":{"metadata":{"abstract_canon_sha256":"5543825bdda8e559387817bf05946583a360cf3fd8002493500605d7d3ce8596","cross_cats_sorted":[],"license":"http://creativecommons.org/licenses/by/4.0/","primary_cat":"astro-ph.HE","submitted_at":"2024-07-12T19:05:24Z","title_canon_sha256":"e33a0f6d28c07df3c8f3c6d1622ef05dd2109d4f74646f7eea5f01720662b47a"},"schema_version":"1.0","source":{"id":"2407.09647","kind":"arxiv","version":2}},"canonical_sha256":"66e032ea33b565977831c46a9691a6c979bf7bc6a2410f25f128be8141895c66","receipt":{"algorithm":"ed25519","builder_version":"pith-number-builder-2026-05-17-v1","canonical_sha256":"66e032ea33b565977831c46a9691a6c979bf7bc6a2410f25f128be8141895c66","first_computed_at":"2026-07-05T10:47:54.923882Z","key_id":"pith-v1-2026-05","kind":"pith_receipt","last_reissued_at":"2026-07-05T10:47:54.923882Z","public_key_fingerprint":"8d4b5ee74e4693bcd1df2446408b0d54","receipt_version":"0.3","signature_b64":"9EeJv208l+J6pQojXafq8SCua+gd62nSnbHcSeslxmkkvnhhInBl16e3z1yZf/c2yH1GoaXwwvf4snyHdto4Ag==","signature_status":"signed_v1","signed_at":"2026-07-05T10:47:54.924413Z","signed_message":"canonical_sha256_bytes"},"source_id":"2407.09647","source_kind":"arxiv","source_version":2}}},"equivocations":[],"invalid_events":[],"applied_event_ids":["sha256:b604b3f6413a5b3d06d6c9cbe3ce53092ab16ac88402260120412ca367c16e5b","sha256:bfcb78501bf17a64027c789df3a6fbc6273c0e304e0f3ad13bd131a95d95e7be"],"state_sha256":"16b1aeb28e5d4c543af805c31973a8f9a864d6daa6d68f0379504510f85fd82c"}