{"bundle_type":"pith_open_graph_bundle","bundle_version":"1.0","pith_number":"pith:2021:BNXOP5YOPOPSMQD2A3OHTDWM5K","short_pith_number":"pith:BNXOP5YO","canonical_record":{"source":{"id":"2109.03262","kind":"arxiv","version":2},"metadata":{"license":"http://creativecommons.org/licenses/by/4.0/","primary_cat":"astro-ph.HE","submitted_at":"2021-09-07T18:02:24Z","cross_cats_sorted":["gr-qc"],"title_canon_sha256":"75a40fb14c276849d76242d9c7ae65e15f95a44afd3b4aa4b1726a1e61ed7aa5","abstract_canon_sha256":"85ef2c263e1d0b4720df1d633536daa30dc2ae0798a5704b9996cb88e9741471"},"schema_version":"1.0"},"canonical_sha256":"0b6ee7f70e7b9f26407a06dc798ecceab2eef51f5f3c1e17b43f101b6fdd9aa0","source":{"kind":"arxiv","id":"2109.03262","version":2},"source_aliases":[{"alias_kind":"arxiv","alias_value":"2109.03262","created_at":"2026-07-05T04:22:51Z"},{"alias_kind":"arxiv_version","alias_value":"2109.03262v2","created_at":"2026-07-05T04:22:51Z"},{"alias_kind":"doi","alias_value":"10.48550/arxiv.2109.03262","created_at":"2026-07-05T04:22:51Z"},{"alias_kind":"pith_short_12","alias_value":"BNXOP5YOPOPS","created_at":"2026-07-05T04:22:51Z"},{"alias_kind":"pith_short_16","alias_value":"BNXOP5YOPOPSMQD2","created_at":"2026-07-05T04:22:51Z"},{"alias_kind":"pith_short_8","alias_value":"BNXOP5YO","created_at":"2026-07-05T04:22:51Z"}],"events":[{"event_type":"record_created","subject_pith_number":"pith:2021:BNXOP5YOPOPSMQD2A3OHTDWM5K","target":"record","payload":{"canonical_record":{"source":{"id":"2109.03262","kind":"arxiv","version":2},"metadata":{"license":"http://creativecommons.org/licenses/by/4.0/","primary_cat":"astro-ph.HE","submitted_at":"2021-09-07T18:02:24Z","cross_cats_sorted":["gr-qc"],"title_canon_sha256":"75a40fb14c276849d76242d9c7ae65e15f95a44afd3b4aa4b1726a1e61ed7aa5","abstract_canon_sha256":"85ef2c263e1d0b4720df1d633536daa30dc2ae0798a5704b9996cb88e9741471"},"schema_version":"1.0"},"canonical_sha256":"0b6ee7f70e7b9f26407a06dc798ecceab2eef51f5f3c1e17b43f101b6fdd9aa0","receipt":{"kind":"pith_receipt","key_id":"pith-v1-2026-05","algorithm":"ed25519","signed_at":"2026-07-05T04:22:51.598617Z","signature_b64":"5YCoHodG9AL1AWOvCPIZVpfdRizQvPljU0M/6HMFBeneb+1pCsTpSyW0sqGCubtIM14vDRnsKAzwM6wEQaTvDw==","signed_message":"canonical_sha256_bytes","builder_version":"pith-number-builder-2026-05-17-v1","receipt_version":"0.3","canonical_sha256":"0b6ee7f70e7b9f26407a06dc798ecceab2eef51f5f3c1e17b43f101b6fdd9aa0","last_reissued_at":"2026-07-05T04:22:51.598185Z","signature_status":"signed_v1","first_computed_at":"2026-07-05T04:22:51.598185Z","public_key_fingerprint":"8d4b5ee74e4693bcd1df2446408b0d54"},"source_kind":"arxiv","source_id":"2109.03262","source_version":2,"attestation_state":"computed"},"signer":{"signer_id":"pith.science","signer_type":"pith_registry","key_id":"pith-v1-2026-05","public_key_fingerprint":"8d4b5ee74e4693bcd1df2446408b0d54"},"created_at":"2026-07-05T04:22:51Z","supersedes":[],"prev_event":null,"signature":{"signature_status":"signed_v1","algorithm":"ed25519","key_id":"pith-v1-2026-05","public_key_fingerprint":"8d4b5ee74e4693bcd1df2446408b0d54","signature_b64":"VMthhOyU9A3jfAhU8w0FT1F5NEJoTOf4RN04o1jbeuPehFEwim3YDYIrCO1a+N3314avIzSIqLny1AgQIQhhCQ==","signed_message":"open_graph_event_sha256_bytes","signed_at":"2026-08-05T03:49:23.286717Z"},"content_sha256":"b0efe3d7809704c6e363645c24b08ff446e9a68896bb957437c66cc86322bea9","schema_version":"1.0","event_id":"sha256:b0efe3d7809704c6e363645c24b08ff446e9a68896bb957437c66cc86322bea9"},{"event_type":"graph_snapshot","subject_pith_number":"pith:2021:BNXOP5YOPOPSMQD2A3OHTDWM5K","target":"graph","payload":{"graph_snapshot":{"paper":{"title":"Electromagnetic Counterparts to Massive Black Hole Mergers","license":"http://creativecommons.org/licenses/by/4.0/","headline":"","cross_cats":["gr-qc"],"primary_cat":"astro-ph.HE","authors_text":"(2) University of Maryland, (3) University of Florida), Laura Blecha (3) ((1) Georgia Institute of Technology, M. Coleman Miller (2), Tamara Bogdanovic (1)","submitted_at":"2021-09-07T18:02:24Z","abstract_excerpt":"The next two decades are expected to open the door to the first coincident detections of electromagnetic (EM) and gravitational wave (GW) signatures associated with massive black hole (MBH) binaries heading for coalescence. These detections will launch a new era of multimessenger astrophysics by expanding this growing field to the low-frequency GW regime and will provide an unprecedented understanding of the evolution of MBHs and galaxies. They will also constitute fundamentally new probes of cosmology and would enable unique tests of gravity. The aim of this Living Review is to provide an int"},"claims":{"count":0,"items":[],"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"source":{"id":"2109.03262","kind":"arxiv","version":2},"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/2109.03262/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":"2026-07-05T04:22:51Z","supersedes":[],"prev_event":null,"signature":{"signature_status":"signed_v1","algorithm":"ed25519","key_id":"pith-v1-2026-05","public_key_fingerprint":"8d4b5ee74e4693bcd1df2446408b0d54","signature_b64":"sxa6WJpsk+1cfKKSWnQSb+PEH4856iT5jHPYtX4VOY7ErmwTYkRlqp7MVXoZwkYL49mXihew3H5vBfI+S5sYDg==","signed_message":"open_graph_event_sha256_bytes","signed_at":"2026-08-05T03:49:23.287180Z"},"content_sha256":"248428bb203fc3fea37780ffe510dd6aeb72957d09e0f34ebd716ce9534ebdda","schema_version":"1.0","event_id":"sha256:248428bb203fc3fea37780ffe510dd6aeb72957d09e0f34ebd716ce9534ebdda"}],"timestamp_proofs":[],"mirror_hints":[{"mirror_type":"https","name":"Pith Resolver","base_url":"https://pith.science","bundle_url":"https://pith.science/pith/BNXOP5YOPOPSMQD2A3OHTDWM5K/bundle.json","state_url":"https://pith.science/pith/BNXOP5YOPOPSMQD2A3OHTDWM5K/state.json","well_known_bundle_url":"https://pith.science/.well-known/pith/BNXOP5YOPOPSMQD2A3OHTDWM5K/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":"2026-08-05T03:49:23Z","links":{"resolver":"https://pith.science/pith/BNXOP5YOPOPSMQD2A3OHTDWM5K","bundle":"https://pith.science/pith/BNXOP5YOPOPSMQD2A3OHTDWM5K/bundle.json","state":"https://pith.science/pith/BNXOP5YOPOPSMQD2A3OHTDWM5K/state.json","well_known_bundle":"https://pith.science/.well-known/pith/BNXOP5YOPOPSMQD2A3OHTDWM5K/bundle.json"},"state":{"state_type":"pith_open_graph_state","state_version":"1.0","pith_number":"pith:2021:BNXOP5YOPOPSMQD2A3OHTDWM5K","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":"85ef2c263e1d0b4720df1d633536daa30dc2ae0798a5704b9996cb88e9741471","cross_cats_sorted":["gr-qc"],"license":"http://creativecommons.org/licenses/by/4.0/","primary_cat":"astro-ph.HE","submitted_at":"2021-09-07T18:02:24Z","title_canon_sha256":"75a40fb14c276849d76242d9c7ae65e15f95a44afd3b4aa4b1726a1e61ed7aa5"},"schema_version":"1.0","source":{"id":"2109.03262","kind":"arxiv","version":2}},"source_aliases":[{"alias_kind":"arxiv","alias_value":"2109.03262","created_at":"2026-07-05T04:22:51Z"},{"alias_kind":"arxiv_version","alias_value":"2109.03262v2","created_at":"2026-07-05T04:22:51Z"},{"alias_kind":"doi","alias_value":"10.48550/arxiv.2109.03262","created_at":"2026-07-05T04:22:51Z"},{"alias_kind":"pith_short_12","alias_value":"BNXOP5YOPOPS","created_at":"2026-07-05T04:22:51Z"},{"alias_kind":"pith_short_16","alias_value":"BNXOP5YOPOPSMQD2","created_at":"2026-07-05T04:22:51Z"},{"alias_kind":"pith_short_8","alias_value":"BNXOP5YO","created_at":"2026-07-05T04:22:51Z"}],"graph_snapshots":[{"event_id":"sha256:248428bb203fc3fea37780ffe510dd6aeb72957d09e0f34ebd716ce9534ebdda","target":"graph","created_at":"2026-07-05T04:22:51Z","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/2109.03262/integrity.json","findings":[],"snapshot_sha256":"c28c3603d3b5d939e8dc4c7e95fa8dfce3d595e45f758748cecf8e644a296938","summary":{"advisory":0,"by_detector":{},"critical":0,"informational":0}},"paper":{"abstract_excerpt":"The next two decades are expected to open the door to the first coincident detections of electromagnetic (EM) and gravitational wave (GW) signatures associated with massive black hole (MBH) binaries heading for coalescence. These detections will launch a new era of multimessenger astrophysics by expanding this growing field to the low-frequency GW regime and will provide an unprecedented understanding of the evolution of MBHs and galaxies. They will also constitute fundamentally new probes of cosmology and would enable unique tests of gravity. The aim of this Living Review is to provide an int","authors_text":"(2) University of Maryland, (3) University of Florida), Laura Blecha (3) ((1) Georgia Institute of Technology, M. Coleman Miller (2), Tamara Bogdanovic (1)","cross_cats":["gr-qc"],"headline":"","license":"http://creativecommons.org/licenses/by/4.0/","primary_cat":"astro-ph.HE","submitted_at":"2021-09-07T18:02:24Z","title":"Electromagnetic Counterparts to Massive Black Hole Mergers"},"references":{"count":0,"internal_anchors":0,"resolved_work":0,"sample":[],"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"source":{"id":"2109.03262","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:b0efe3d7809704c6e363645c24b08ff446e9a68896bb957437c66cc86322bea9","target":"record","created_at":"2026-07-05T04:22:51Z","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":"85ef2c263e1d0b4720df1d633536daa30dc2ae0798a5704b9996cb88e9741471","cross_cats_sorted":["gr-qc"],"license":"http://creativecommons.org/licenses/by/4.0/","primary_cat":"astro-ph.HE","submitted_at":"2021-09-07T18:02:24Z","title_canon_sha256":"75a40fb14c276849d76242d9c7ae65e15f95a44afd3b4aa4b1726a1e61ed7aa5"},"schema_version":"1.0","source":{"id":"2109.03262","kind":"arxiv","version":2}},"canonical_sha256":"0b6ee7f70e7b9f26407a06dc798ecceab2eef51f5f3c1e17b43f101b6fdd9aa0","receipt":{"algorithm":"ed25519","builder_version":"pith-number-builder-2026-05-17-v1","canonical_sha256":"0b6ee7f70e7b9f26407a06dc798ecceab2eef51f5f3c1e17b43f101b6fdd9aa0","first_computed_at":"2026-07-05T04:22:51.598185Z","key_id":"pith-v1-2026-05","kind":"pith_receipt","last_reissued_at":"2026-07-05T04:22:51.598185Z","public_key_fingerprint":"8d4b5ee74e4693bcd1df2446408b0d54","receipt_version":"0.3","signature_b64":"5YCoHodG9AL1AWOvCPIZVpfdRizQvPljU0M/6HMFBeneb+1pCsTpSyW0sqGCubtIM14vDRnsKAzwM6wEQaTvDw==","signature_status":"signed_v1","signed_at":"2026-07-05T04:22:51.598617Z","signed_message":"canonical_sha256_bytes"},"source_id":"2109.03262","source_kind":"arxiv","source_version":2}}},"equivocations":[],"invalid_events":[],"applied_event_ids":["sha256:b0efe3d7809704c6e363645c24b08ff446e9a68896bb957437c66cc86322bea9","sha256:248428bb203fc3fea37780ffe510dd6aeb72957d09e0f34ebd716ce9534ebdda"],"state_sha256":"495d138e4485ba381ecbbe468d9165f235784354c86099718d73b4c03a3dd349"},"bundle_signature":{"signature_status":"signed_v1","algorithm":"ed25519","key_id":"pith-v1-2026-05","public_key_fingerprint":"8d4b5ee74e4693bcd1df2446408b0d54","signature_b64":"ioIHjUbQ+CnV66nZF/cBayLBb4VEe+GpYGzmdyh+KGT2jnLyDPUJqaoa71cnOnvzAZnmM2pFN4o+RTr/Ig+5CA==","signed_message":"bundle_sha256_bytes","signed_at":"2026-08-05T03:49:23.290133Z","bundle_sha256":"96db1b29de2806ea09f615999449bfd9dbb430ce3046900efa1bacd6ca84a620"}}