{"state_type":"pith_open_graph_state","state_version":"1.0","pith_number":"pith:2021:IGIS6A4FNW4CDJXHN6SDYR7ZF3","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":"c2bde6109516024df9caca5ccdd2060236deb196b96f9c7ce787cf4e10125470","cross_cats_sorted":[],"license":"http://creativecommons.org/licenses/by/4.0/","primary_cat":"astro-ph.GA","submitted_at":"2021-10-11T21:14:59Z","title_canon_sha256":"0d5171917908e8a327e736406932c45dae244309adb0256e3687a18620471bf0"},"schema_version":"1.0","source":{"id":"2110.05615","kind":"arxiv","version":4}},"source_aliases":[{"alias_kind":"arxiv","alias_value":"2110.05615","created_at":"2026-07-05T05:01:16Z"},{"alias_kind":"arxiv_version","alias_value":"2110.05615v4","created_at":"2026-07-05T05:01:16Z"},{"alias_kind":"doi","alias_value":"10.48550/arxiv.2110.05615","created_at":"2026-07-05T05:01:16Z"},{"alias_kind":"pith_short_12","alias_value":"IGIS6A4FNW4C","created_at":"2026-07-05T05:01:16Z"},{"alias_kind":"pith_short_16","alias_value":"IGIS6A4FNW4CDJXH","created_at":"2026-07-05T05:01:16Z"},{"alias_kind":"pith_short_8","alias_value":"IGIS6A4F","created_at":"2026-07-05T05:01:16Z"}],"graph_snapshots":[{"event_id":"sha256:4f663db38ede4ece4388cfa241a8a325305c05e8c407642acd72d52a8df4fb4f","target":"graph","created_at":"2026-07-05T05:01:16Z","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/2110.05615/integrity.json","findings":[],"snapshot_sha256":"c28c3603d3b5d939e8dc4c7e95fa8dfce3d595e45f758748cecf8e644a296938","summary":{"advisory":0,"by_detector":{},"critical":0,"informational":0}},"paper":{"abstract_excerpt":"Spirals in galaxies have long been thought to be caused by gravitational instability in the stellar component of the disk, but discerning the precise mechanism had proved elusive. Tidal interactions, and perhaps bars, may provoke some spiral responses, but spirals in many galaxies must be self-excited. We survey the relevant observational data and aspects of disk dynamical theory. The origin of the recurring spiral patterns in simulations of isolated disk galaxies has recently become clear and it is likely that the mechanism is the same in real galaxies, although evidence to confirm this suppo","authors_text":"J. A. Sellwood (Steward Observatory), Karen L. Masters (Haverford College)","cross_cats":[],"headline":"","license":"http://creativecommons.org/licenses/by/4.0/","primary_cat":"astro-ph.GA","submitted_at":"2021-10-11T21:14:59Z","title":"Spirals in galaxies"},"references":{"count":0,"internal_anchors":0,"resolved_work":0,"sample":[],"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"source":{"id":"2110.05615","kind":"arxiv","version":4},"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":"sha256:88ff1af9556dfa0a30bd2b19dd9afef6d31bc125e4ff94e9520f1d5ef4ea22fc","target":"record","created_at":"2026-07-05T05:01:16Z","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":"c2bde6109516024df9caca5ccdd2060236deb196b96f9c7ce787cf4e10125470","cross_cats_sorted":[],"license":"http://creativecommons.org/licenses/by/4.0/","primary_cat":"astro-ph.GA","submitted_at":"2021-10-11T21:14:59Z","title_canon_sha256":"0d5171917908e8a327e736406932c45dae244309adb0256e3687a18620471bf0"},"schema_version":"1.0","source":{"id":"2110.05615","kind":"arxiv","version":4}},"canonical_sha256":"41912f03856db821a6e76fa43c47f92ef8a0c80ad91cc8151a40d84a50d137c8","receipt":{"algorithm":"ed25519","builder_version":"pith-number-builder-2026-05-17-v1","canonical_sha256":"41912f03856db821a6e76fa43c47f92ef8a0c80ad91cc8151a40d84a50d137c8","first_computed_at":"2026-07-05T05:01:16.149362Z","key_id":"pith-v1-2026-05","kind":"pith_receipt","last_reissued_at":"2026-07-05T05:01:16.149362Z","public_key_fingerprint":"8d4b5ee74e4693bcd1df2446408b0d54","receipt_version":"0.3","signature_b64":"kqGnN/alY/KjjvKgfh32dL4ZSqVfuhjniYtUkfZCO1yRjWiHc07lqZyCa8E4q/W+dBx1RfJoWb6kBq9iofr4Cw==","signature_status":"signed_v1","signed_at":"2026-07-05T05:01:16.149840Z","signed_message":"canonical_sha256_bytes"},"source_id":"2110.05615","source_kind":"arxiv","source_version":4}}},"equivocations":[],"invalid_events":[],"applied_event_ids":["sha256:88ff1af9556dfa0a30bd2b19dd9afef6d31bc125e4ff94e9520f1d5ef4ea22fc","sha256:4f663db38ede4ece4388cfa241a8a325305c05e8c407642acd72d52a8df4fb4f"],"state_sha256":"1da34ad1f8a2c4fe7ca1b2e13edb6fbd2ddd4d50e66d4a85dbf54841633c5259"}