{"bundle_type":"pith_open_graph_bundle","bundle_version":"1.0","pith_number":"pith:2021:Q3Z4OAYR7UE6T4ZQJYJU5EVG22","short_pith_number":"pith:Q3Z4OAYR","canonical_record":{"source":{"id":"2105.01169","kind":"arxiv","version":1},"metadata":{"license":"http://creativecommons.org/licenses/by/4.0/","primary_cat":"astro-ph.HE","submitted_at":"2021-05-03T21:12:04Z","cross_cats_sorted":["astro-ph.GA"],"title_canon_sha256":"de876f357e3b617131f22ea86f301d922fa3225d52cd518509959fa42ca60016","abstract_canon_sha256":"af12adb92feecc1b2ff6985094883668d6f2bb01fe1c2d33bcdcdfc89723fec4"},"schema_version":"1.0"},"canonical_sha256":"86f3c70311fd09e9f3304e134e92a6d690e1e1053ad027bdefeede422b974684","source":{"kind":"arxiv","id":"2105.01169","version":1},"source_aliases":[{"alias_kind":"arxiv","alias_value":"2105.01169","created_at":"2026-07-05T02:37:14Z"},{"alias_kind":"arxiv_version","alias_value":"2105.01169v1","created_at":"2026-07-05T02:37:14Z"},{"alias_kind":"doi","alias_value":"10.48550/arxiv.2105.01169","created_at":"2026-07-05T02:37:14Z"},{"alias_kind":"pith_short_12","alias_value":"Q3Z4OAYR7UE6","created_at":"2026-07-05T02:37:14Z"},{"alias_kind":"pith_short_16","alias_value":"Q3Z4OAYR7UE6T4ZQ","created_at":"2026-07-05T02:37:14Z"},{"alias_kind":"pith_short_8","alias_value":"Q3Z4OAYR","created_at":"2026-07-05T02:37:14Z"}],"events":[{"event_type":"record_created","subject_pith_number":"pith:2021:Q3Z4OAYR7UE6T4ZQJYJU5EVG22","target":"record","payload":{"canonical_record":{"source":{"id":"2105.01169","kind":"arxiv","version":1},"metadata":{"license":"http://creativecommons.org/licenses/by/4.0/","primary_cat":"astro-ph.HE","submitted_at":"2021-05-03T21:12:04Z","cross_cats_sorted":["astro-ph.GA"],"title_canon_sha256":"de876f357e3b617131f22ea86f301d922fa3225d52cd518509959fa42ca60016","abstract_canon_sha256":"af12adb92feecc1b2ff6985094883668d6f2bb01fe1c2d33bcdcdfc89723fec4"},"schema_version":"1.0"},"canonical_sha256":"86f3c70311fd09e9f3304e134e92a6d690e1e1053ad027bdefeede422b974684","receipt":{"kind":"pith_receipt","key_id":"pith-v1-2026-05","algorithm":"ed25519","signed_at":"2026-07-05T02:37:14.065629Z","signature_b64":"vu5TtxkBIKRTbASI61oDzkM0XZFGuF3M8Ye4xq8PIbswaPO8yyIDfHMFEZ0+6hr/5ixHsaBewYBD33KUiiaoDQ==","signed_message":"canonical_sha256_bytes","builder_version":"pith-number-builder-2026-05-17-v1","receipt_version":"0.3","canonical_sha256":"86f3c70311fd09e9f3304e134e92a6d690e1e1053ad027bdefeede422b974684","last_reissued_at":"2026-07-05T02:37:14.065116Z","signature_status":"signed_v1","first_computed_at":"2026-07-05T02:37:14.065116Z","public_key_fingerprint":"8d4b5ee74e4693bcd1df2446408b0d54"},"source_kind":"arxiv","source_id":"2105.01169","source_version":1,"attestation_state":"computed"},"signer":{"signer_id":"pith.science","signer_type":"pith_registry","key_id":"pith-v1-2026-05","public_key_fingerprint":"8d4b5ee74e4693bcd1df2446408b0d54"},"created_at":"2026-07-05T02:37:14Z","supersedes":[],"prev_event":null,"signature":{"signature_status":"signed_v1","algorithm":"ed25519","key_id":"pith-v1-2026-05","public_key_fingerprint":"8d4b5ee74e4693bcd1df2446408b0d54","signature_b64":"LSiiQLjEjfrc0H0vgez9cuV9dUWPNEMviVqONGUOZTdtpBDAFn/ivda4capSiSO0uy6vmaSpo7DlBMIvcnPqCg==","signed_message":"open_graph_event_sha256_bytes","signed_at":"2026-08-17T23:13:33.540958Z"},"content_sha256":"2057570dc527ed768c01a42c6fae7ba728f49b2b301f42994ba79a85fe14153d","schema_version":"1.0","event_id":"sha256:2057570dc527ed768c01a42c6fae7ba728f49b2b301f42994ba79a85fe14153d"},{"event_type":"graph_snapshot","subject_pith_number":"pith:2021:Q3Z4OAYR7UE6T4ZQJYJU5EVG22","target":"graph","payload":{"graph_snapshot":{"paper":{"title":"First M87 Event Horizon Telescope Results. VII. Polarization of the Ring","license":"http://creativecommons.org/licenses/by/4.0/","headline":"","cross_cats":["astro-ph.GA"],"primary_cat":"astro-ph.HE","authors_text":"The Event Horizon Telescope Collaboration","submitted_at":"2021-05-03T21:12:04Z","abstract_excerpt":"In 2017 April, the Event Horizon Telescope (EHT) observed the near-horizon region around the supermassive black hole at the core of the M87 galaxy. These 1.3 mm wavelength observations revealed a compact asymmetric ring-like source morphology. This structure originates from synchrotron emission produced by relativistic plasma located in the immediate vicinity of the black hole. Here we present the corresponding linear-polarimetric EHT images of the center of M87. We find that only a part of the ring is significantly polarized. The resolved fractional linear polarization has a maximum located i"},"claims":{"count":0,"items":[],"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"source":{"id":"2105.01169","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/2105.01169/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"},"verdict_id":null},"signer":{"signer_id":"pith.science","signer_type":"pith_registry","key_id":"pith-v1-2026-05","public_key_fingerprint":"8d4b5ee74e4693bcd1df2446408b0d54"},"created_at":"2026-07-05T02:37:14Z","supersedes":[],"prev_event":null,"signature":{"signature_status":"signed_v1","algorithm":"ed25519","key_id":"pith-v1-2026-05","public_key_fingerprint":"8d4b5ee74e4693bcd1df2446408b0d54","signature_b64":"UJll6bkd2mF7F2U9gJY/QbtOzAl5CCAXr2or/7Cl5V0op29fKPu2JM/hRGkzrfDIn0uI6CLPMIsGS/M3u9OBBg==","signed_message":"open_graph_event_sha256_bytes","signed_at":"2026-08-17T23:13:33.542016Z"},"content_sha256":"c345c47f3023d446fe1f5b5ef2fe630a85a4ab0d2eaca2b0b8eb20fcffcc4718","schema_version":"1.0","event_id":"sha256:c345c47f3023d446fe1f5b5ef2fe630a85a4ab0d2eaca2b0b8eb20fcffcc4718"}],"timestamp_proofs":[],"mirror_hints":[{"mirror_type":"https","name":"Pith Resolver","base_url":"https://pith.science","bundle_url":"https://pith.science/pith/Q3Z4OAYR7UE6T4ZQJYJU5EVG22/bundle.json","state_url":"https://pith.science/pith/Q3Z4OAYR7UE6T4ZQJYJU5EVG22/state.json","well_known_bundle_url":"https://pith.science/.well-known/pith/Q3Z4OAYR7UE6T4ZQJYJU5EVG22/bundle.json","status":"primary"}],"public_keys":[{"key_id":"pith-v1-2026-05","algorithm":"ed25519","format":"raw","public_key_b64":"stVStoiQhXFxp4s2pdzPNoqVNBMojDU/fJ2db5S3CbM=","public_key_hex":"b2d552b68890857171a78b36a5dccf368a953413288c353f7c9d9d6f94b709b3","fingerprint_sha256_b32_first128bits":"RVFV5Z2OI2J3ZUO7ERDEBCYNKS","fingerprint_sha256_hex":"8d4b5ee74e4693bcd1df2446408b0d54","rotates_at":null,"url":"https://pith.science/pith-signing-key.json","notes":"Pith uses this Ed25519 key to sign canonical record SHA-256 digests. Verify with: ed25519_verify(public_key, message=canonical_sha256_bytes, signature=base64decode(signature_b64))."}],"merge_version":"pith-open-graph-merge-v1","built_at":"2026-08-17T23:13:33Z","links":{"resolver":"https://pith.science/pith/Q3Z4OAYR7UE6T4ZQJYJU5EVG22","bundle":"https://pith.science/pith/Q3Z4OAYR7UE6T4ZQJYJU5EVG22/bundle.json","state":"https://pith.science/pith/Q3Z4OAYR7UE6T4ZQJYJU5EVG22/state.json","well_known_bundle":"https://pith.science/.well-known/pith/Q3Z4OAYR7UE6T4ZQJYJU5EVG22/bundle.json"},"state":{"state_type":"pith_open_graph_state","state_version":"1.0","pith_number":"pith:2021:Q3Z4OAYR7UE6T4ZQJYJU5EVG22","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":"af12adb92feecc1b2ff6985094883668d6f2bb01fe1c2d33bcdcdfc89723fec4","cross_cats_sorted":["astro-ph.GA"],"license":"http://creativecommons.org/licenses/by/4.0/","primary_cat":"astro-ph.HE","submitted_at":"2021-05-03T21:12:04Z","title_canon_sha256":"de876f357e3b617131f22ea86f301d922fa3225d52cd518509959fa42ca60016"},"schema_version":"1.0","source":{"id":"2105.01169","kind":"arxiv","version":1}},"source_aliases":[{"alias_kind":"arxiv","alias_value":"2105.01169","created_at":"2026-07-05T02:37:14Z"},{"alias_kind":"arxiv_version","alias_value":"2105.01169v1","created_at":"2026-07-05T02:37:14Z"},{"alias_kind":"doi","alias_value":"10.48550/arxiv.2105.01169","created_at":"2026-07-05T02:37:14Z"},{"alias_kind":"pith_short_12","alias_value":"Q3Z4OAYR7UE6","created_at":"2026-07-05T02:37:14Z"},{"alias_kind":"pith_short_16","alias_value":"Q3Z4OAYR7UE6T4ZQ","created_at":"2026-07-05T02:37:14Z"},{"alias_kind":"pith_short_8","alias_value":"Q3Z4OAYR","created_at":"2026-07-05T02:37:14Z"}],"graph_snapshots":[{"event_id":"sha256:c345c47f3023d446fe1f5b5ef2fe630a85a4ab0d2eaca2b0b8eb20fcffcc4718","target":"graph","created_at":"2026-07-05T02:37:14Z","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/2105.01169/integrity.json","findings":[],"snapshot_sha256":"c28c3603d3b5d939e8dc4c7e95fa8dfce3d595e45f758748cecf8e644a296938","summary":{"advisory":0,"by_detector":{},"critical":0,"informational":0}},"paper":{"abstract_excerpt":"In 2017 April, the Event Horizon Telescope (EHT) observed the near-horizon region around the supermassive black hole at the core of the M87 galaxy. These 1.3 mm wavelength observations revealed a compact asymmetric ring-like source morphology. This structure originates from synchrotron emission produced by relativistic plasma located in the immediate vicinity of the black hole. Here we present the corresponding linear-polarimetric EHT images of the center of M87. We find that only a part of the ring is significantly polarized. The resolved fractional linear polarization has a maximum located i","authors_text":"The Event Horizon Telescope Collaboration","cross_cats":["astro-ph.GA"],"headline":"","license":"http://creativecommons.org/licenses/by/4.0/","primary_cat":"astro-ph.HE","submitted_at":"2021-05-03T21:12:04Z","title":"First M87 Event Horizon Telescope Results. VII. Polarization of the Ring"},"references":{"count":0,"internal_anchors":0,"resolved_work":0,"sample":[],"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"source":{"id":"2105.01169","kind":"arxiv","version":1},"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":"sha256:2057570dc527ed768c01a42c6fae7ba728f49b2b301f42994ba79a85fe14153d","target":"record","created_at":"2026-07-05T02:37:14Z","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":"af12adb92feecc1b2ff6985094883668d6f2bb01fe1c2d33bcdcdfc89723fec4","cross_cats_sorted":["astro-ph.GA"],"license":"http://creativecommons.org/licenses/by/4.0/","primary_cat":"astro-ph.HE","submitted_at":"2021-05-03T21:12:04Z","title_canon_sha256":"de876f357e3b617131f22ea86f301d922fa3225d52cd518509959fa42ca60016"},"schema_version":"1.0","source":{"id":"2105.01169","kind":"arxiv","version":1}},"canonical_sha256":"86f3c70311fd09e9f3304e134e92a6d690e1e1053ad027bdefeede422b974684","receipt":{"algorithm":"ed25519","builder_version":"pith-number-builder-2026-05-17-v1","canonical_sha256":"86f3c70311fd09e9f3304e134e92a6d690e1e1053ad027bdefeede422b974684","first_computed_at":"2026-07-05T02:37:14.065116Z","key_id":"pith-v1-2026-05","kind":"pith_receipt","last_reissued_at":"2026-07-05T02:37:14.065116Z","public_key_fingerprint":"8d4b5ee74e4693bcd1df2446408b0d54","receipt_version":"0.3","signature_b64":"vu5TtxkBIKRTbASI61oDzkM0XZFGuF3M8Ye4xq8PIbswaPO8yyIDfHMFEZ0+6hr/5ixHsaBewYBD33KUiiaoDQ==","signature_status":"signed_v1","signed_at":"2026-07-05T02:37:14.065629Z","signed_message":"canonical_sha256_bytes"},"source_id":"2105.01169","source_kind":"arxiv","source_version":1}}},"equivocations":[],"invalid_events":[],"applied_event_ids":["sha256:2057570dc527ed768c01a42c6fae7ba728f49b2b301f42994ba79a85fe14153d","sha256:c345c47f3023d446fe1f5b5ef2fe630a85a4ab0d2eaca2b0b8eb20fcffcc4718"],"state_sha256":"248cdae227dfe2f77b91876f8b23cfb6999fcc22230d02cc9039676f5bb096a6"},"bundle_signature":{"signature_status":"signed_v1","algorithm":"ed25519","key_id":"pith-v1-2026-05","public_key_fingerprint":"8d4b5ee74e4693bcd1df2446408b0d54","signature_b64":"3JiBsxeQbFy3yfMiPROHkI6MiC7K3qhli+EGfi6gxu1Xkns7N5oCivFQ9XRtR8Zf/7jF/rtRtK4Mb/vySnaBDA==","signed_message":"bundle_sha256_bytes","signed_at":"2026-08-17T23:13:33.548109Z","bundle_sha256":"e75caa0ce63beaba5e32b3fdf3cdebc8d84eaf6f8e30bb2d845c38e2cc996a2e"}}