{"state_type":"pith_open_graph_state","state_version":"1.0","pith_number":"pith:2020:X4W5DYW6KKTSUT6AA6WCFWFWTZ","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":"43b52dc4f7a2f8c2e7627e323746b7ab4b527fa06e05eedae62db7b6f2e6a1fd","cross_cats_sorted":["astro-ph.CO","astro-ph.HE"],"license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","primary_cat":"astro-ph.SR","submitted_at":"2020-09-14T17:17:18Z","title_canon_sha256":"9d6aa21695211cd0ef7ba06002f5e687ff96a7bfbec75d88814869909c9f1455"},"schema_version":"1.0","source":{"id":"2009.06585","kind":"arxiv","version":2}},"source_aliases":[{"alias_kind":"arxiv","alias_value":"2009.06585","created_at":"2026-07-05T02:04:58Z"},{"alias_kind":"arxiv_version","alias_value":"2009.06585v2","created_at":"2026-07-05T02:04:58Z"},{"alias_kind":"doi","alias_value":"10.48550/arxiv.2009.06585","created_at":"2026-07-05T02:04:58Z"},{"alias_kind":"pith_short_12","alias_value":"X4W5DYW6KKTS","created_at":"2026-07-05T02:04:58Z"},{"alias_kind":"pith_short_16","alias_value":"X4W5DYW6KKTSUT6A","created_at":"2026-07-05T02:04:58Z"},{"alias_kind":"pith_short_8","alias_value":"X4W5DYW6","created_at":"2026-07-05T02:04:58Z"}],"graph_snapshots":[{"event_id":"sha256:fedabeddbebc1e9beeca196eea45556f526483bafd1f2e474a564d7a361ca6c1","target":"graph","created_at":"2026-07-05T02:04:58Z","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/2009.06585/integrity.json","findings":[],"snapshot_sha256":"c28c3603d3b5d939e8dc4c7e95fa8dfce3d595e45f758748cecf8e644a296938","summary":{"advisory":0,"by_detector":{},"critical":0,"informational":0}},"paper":{"abstract_excerpt":"GW190521 challenges our understanding of the late-stage evolution of massive stars and the effects of the pair-instability in particular. We discuss the possibility that stars at low or zero metallicity could retain most of their hydrogen envelope until the pre-supernova stage, avoid the pulsational pair-instability regime and produce a black hole with a mass in the mass gap by fallback. We present a series of new stellar evolution models at zero and low metallicity computed with the Geneva and MESA stellar evolution codes and compare to existing grids of models. Models with a metallicity in t","authors_text":"Cyril Georgy, Eoin J. Farrell, Etienne Kaiser, Georges Meynet, Jose H. Groh, Laura Murphy, Raphael Hirschi, Sylvia Ekstr\\\"om","cross_cats":["astro-ph.CO","astro-ph.HE"],"headline":"","license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","primary_cat":"astro-ph.SR","submitted_at":"2020-09-14T17:17:18Z","title":"Is GW190521 the merger of black holes from the first stellar generations?"},"references":{"count":0,"internal_anchors":0,"resolved_work":0,"sample":[],"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"source":{"id":"2009.06585","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":"sha256:0d5aef0714b19d0f25efa3cf7f2965eddae3736da4da0e5a669bbfb1f836e443","target":"record","created_at":"2026-07-05T02:04:58Z","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":"43b52dc4f7a2f8c2e7627e323746b7ab4b527fa06e05eedae62db7b6f2e6a1fd","cross_cats_sorted":["astro-ph.CO","astro-ph.HE"],"license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","primary_cat":"astro-ph.SR","submitted_at":"2020-09-14T17:17:18Z","title_canon_sha256":"9d6aa21695211cd0ef7ba06002f5e687ff96a7bfbec75d88814869909c9f1455"},"schema_version":"1.0","source":{"id":"2009.06585","kind":"arxiv","version":2}},"canonical_sha256":"bf2dd1e2de52a72a4fc007ac22d8b69e7ebc372d62fe2c5a47f8304cda8e8cb4","receipt":{"algorithm":"ed25519","builder_version":"pith-number-builder-2026-05-17-v1","canonical_sha256":"bf2dd1e2de52a72a4fc007ac22d8b69e7ebc372d62fe2c5a47f8304cda8e8cb4","first_computed_at":"2026-07-05T02:04:58.137994Z","key_id":"pith-v1-2026-05","kind":"pith_receipt","last_reissued_at":"2026-07-05T02:04:58.137994Z","public_key_fingerprint":"8d4b5ee74e4693bcd1df2446408b0d54","receipt_version":"0.3","signature_b64":"btxuVSrbZMy3AEei7Z/+oAfH6HlJPKijW8tHYpmE7pijJ1u1hhzPLYUOALPPoK9fftv85PXK7kOV8OgFmfp6Aw==","signature_status":"signed_v1","signed_at":"2026-07-05T02:04:58.138494Z","signed_message":"canonical_sha256_bytes"},"source_id":"2009.06585","source_kind":"arxiv","source_version":2}}},"equivocations":[],"invalid_events":[],"applied_event_ids":["sha256:0d5aef0714b19d0f25efa3cf7f2965eddae3736da4da0e5a669bbfb1f836e443","sha256:fedabeddbebc1e9beeca196eea45556f526483bafd1f2e474a564d7a361ca6c1"],"state_sha256":"957421ac0ab89a9960b99ae6c99116a05074cc8e02a6fb122ece2e1b2d76bdd2"}