{"bundle_type":"pith_open_graph_bundle","bundle_version":"1.0","pith_number":"pith:2018:4KJG7ZC5SQLKMCHDDGXSKG5YCY","short_pith_number":"pith:4KJG7ZC5","canonical_record":{"source":{"id":"1806.04091","kind":"arxiv","version":2},"metadata":{"license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","primary_cat":"gr-qc","submitted_at":"2018-06-11T16:24:50Z","cross_cats_sorted":[],"title_canon_sha256":"0f03dc7f2a678825a34de4bcddffb21f73d855619478e291f0380014c0f0d50b","abstract_canon_sha256":"ec3ec8687fabf3e70acef7f48858a9f18b22df377b38b9c3322aaefc98cf3d5d"},"schema_version":"1.0"},"canonical_sha256":"e2926fe45d9416a608e319af251bb816345e5b2ae563b409f9c8e2d88bbf9b20","source":{"kind":"arxiv","id":"1806.04091","version":2},"source_aliases":[{"alias_kind":"arxiv","alias_value":"1806.04091","created_at":"2026-05-17T23:48:45Z"},{"alias_kind":"arxiv_version","alias_value":"1806.04091v2","created_at":"2026-05-17T23:48:45Z"},{"alias_kind":"doi","alias_value":"10.48550/arxiv.1806.04091","created_at":"2026-05-17T23:48:45Z"},{"alias_kind":"pith_short_12","alias_value":"4KJG7ZC5SQLK","created_at":"2026-05-18T12:32:05Z"},{"alias_kind":"pith_short_16","alias_value":"4KJG7ZC5SQLKMCHD","created_at":"2026-05-18T12:32:05Z"},{"alias_kind":"pith_short_8","alias_value":"4KJG7ZC5","created_at":"2026-05-18T12:32:05Z"}],"events":[{"event_type":"record_created","subject_pith_number":"pith:2018:4KJG7ZC5SQLKMCHDDGXSKG5YCY","target":"record","payload":{"canonical_record":{"source":{"id":"1806.04091","kind":"arxiv","version":2},"metadata":{"license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","primary_cat":"gr-qc","submitted_at":"2018-06-11T16:24:50Z","cross_cats_sorted":[],"title_canon_sha256":"0f03dc7f2a678825a34de4bcddffb21f73d855619478e291f0380014c0f0d50b","abstract_canon_sha256":"ec3ec8687fabf3e70acef7f48858a9f18b22df377b38b9c3322aaefc98cf3d5d"},"schema_version":"1.0"},"canonical_sha256":"e2926fe45d9416a608e319af251bb816345e5b2ae563b409f9c8e2d88bbf9b20","receipt":{"kind":"pith_receipt","key_id":"pith-v1-2026-05","algorithm":"ed25519","signed_at":"2026-05-17T23:48:45.790494Z","signature_b64":"+WE2yxZq7BAcoeBFmrBLpLPHgkEva6W9uHZstrYn0L6ysdoAMPZXfHrZn41CyztFZ4KMyECucCDZ45lZDUQ6DA==","signed_message":"canonical_sha256_bytes","builder_version":"pith-number-builder-2026-05-17-v1","receipt_version":"0.3","canonical_sha256":"e2926fe45d9416a608e319af251bb816345e5b2ae563b409f9c8e2d88bbf9b20","last_reissued_at":"2026-05-17T23:48:45.789840Z","signature_status":"signed_v1","first_computed_at":"2026-05-17T23:48:45.789840Z","public_key_fingerprint":"8d4b5ee74e4693bcd1df2446408b0d54"},"source_kind":"arxiv","source_id":"1806.04091","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":"2026-05-17T23:48:45Z","supersedes":[],"prev_event":null,"signature":{"signature_status":"signed_v1","algorithm":"ed25519","key_id":"pith-v1-2026-05","public_key_fingerprint":"8d4b5ee74e4693bcd1df2446408b0d54","signature_b64":"6/j2hHcUsFNGANHX+7ZmV93djSMi6kpLTtm0J/gMwwt+zySjhR0kt81YJPsU8f8Sxv0N4K9r1qAp1aNAISrEAA==","signed_message":"open_graph_event_sha256_bytes","signed_at":"2026-05-25T10:58:42.552635Z"},"content_sha256":"f7f21ed77a244674c8134636ab8cf073b502a8d1ada1f2938d84d41e0cea1141","schema_version":"1.0","event_id":"sha256:f7f21ed77a244674c8134636ab8cf073b502a8d1ada1f2938d84d41e0cea1141"},{"event_type":"graph_snapshot","subject_pith_number":"pith:2018:4KJG7ZC5SQLKMCHDDGXSKG5YCY","target":"graph","payload":{"graph_snapshot":{"paper":{"title":"On the connection of spacetime separability and spherical photon orbits","license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","headline":"","cross_cats":[],"primary_cat":"gr-qc","authors_text":"George Pappas, Kostas Glampedakis","submitted_at":"2018-06-11T16:24:50Z","abstract_excerpt":"The notion of non-equatorial spherical photon orbits is among the very special properties of the Kerr spacetime of rotating black holes and is one that leaves a clear mark on the electromagnetic and gravitational wave signature of these objects. In principle, one could use observations like the shadow a black hole casts when is externally illuminated or the gravitational quasi-normal mode ringdown of merging black holes in order to identify the Kerr metric via its light-ring and spherical photon orbit structure, or perhaps look for the presence of more exotic non-Kerr ultracompact objects. Thi"},"claims":{"count":0,"items":[],"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"source":{"id":"1806.04091","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":""},"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":"2026-05-17T23:48:45Z","supersedes":[],"prev_event":null,"signature":{"signature_status":"signed_v1","algorithm":"ed25519","key_id":"pith-v1-2026-05","public_key_fingerprint":"8d4b5ee74e4693bcd1df2446408b0d54","signature_b64":"PSN5HjyJwzNUxr/h/uATDv6CrzXvJiyVtv2YjH07GYDGm6hK0qtGWBh2NOPThjxR1SG7qVb6r68Bkq5cJIhLBw==","signed_message":"open_graph_event_sha256_bytes","signed_at":"2026-05-25T10:58:42.553359Z"},"content_sha256":"9266544ca5dc506edf399f00fda4d7864ed02bcb613b868fde41a383d89d048e","schema_version":"1.0","event_id":"sha256:9266544ca5dc506edf399f00fda4d7864ed02bcb613b868fde41a383d89d048e"}],"timestamp_proofs":[],"mirror_hints":[{"mirror_type":"https","name":"Pith Resolver","base_url":"https://pith.science","bundle_url":"https://pith.science/pith/4KJG7ZC5SQLKMCHDDGXSKG5YCY/bundle.json","state_url":"https://pith.science/pith/4KJG7ZC5SQLKMCHDDGXSKG5YCY/state.json","well_known_bundle_url":"https://pith.science/.well-known/pith/4KJG7ZC5SQLKMCHDDGXSKG5YCY/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":"2026-05-25T10:58:42Z","links":{"resolver":"https://pith.science/pith/4KJG7ZC5SQLKMCHDDGXSKG5YCY","bundle":"https://pith.science/pith/4KJG7ZC5SQLKMCHDDGXSKG5YCY/bundle.json","state":"https://pith.science/pith/4KJG7ZC5SQLKMCHDDGXSKG5YCY/state.json","well_known_bundle":"https://pith.science/.well-known/pith/4KJG7ZC5SQLKMCHDDGXSKG5YCY/bundle.json"},"state":{"state_type":"pith_open_graph_state","state_version":"1.0","pith_number":"pith:2018:4KJG7ZC5SQLKMCHDDGXSKG5YCY","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":"ec3ec8687fabf3e70acef7f48858a9f18b22df377b38b9c3322aaefc98cf3d5d","cross_cats_sorted":[],"license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","primary_cat":"gr-qc","submitted_at":"2018-06-11T16:24:50Z","title_canon_sha256":"0f03dc7f2a678825a34de4bcddffb21f73d855619478e291f0380014c0f0d50b"},"schema_version":"1.0","source":{"id":"1806.04091","kind":"arxiv","version":2}},"source_aliases":[{"alias_kind":"arxiv","alias_value":"1806.04091","created_at":"2026-05-17T23:48:45Z"},{"alias_kind":"arxiv_version","alias_value":"1806.04091v2","created_at":"2026-05-17T23:48:45Z"},{"alias_kind":"doi","alias_value":"10.48550/arxiv.1806.04091","created_at":"2026-05-17T23:48:45Z"},{"alias_kind":"pith_short_12","alias_value":"4KJG7ZC5SQLK","created_at":"2026-05-18T12:32:05Z"},{"alias_kind":"pith_short_16","alias_value":"4KJG7ZC5SQLKMCHD","created_at":"2026-05-18T12:32:05Z"},{"alias_kind":"pith_short_8","alias_value":"4KJG7ZC5","created_at":"2026-05-18T12:32:05Z"}],"graph_snapshots":[{"event_id":"sha256:9266544ca5dc506edf399f00fda4d7864ed02bcb613b868fde41a383d89d048e","target":"graph","created_at":"2026-05-17T23:48:45Z","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"},"paper":{"abstract_excerpt":"The notion of non-equatorial spherical photon orbits is among the very special properties of the Kerr spacetime of rotating black holes and is one that leaves a clear mark on the electromagnetic and gravitational wave signature of these objects. In principle, one could use observations like the shadow a black hole casts when is externally illuminated or the gravitational quasi-normal mode ringdown of merging black holes in order to identify the Kerr metric via its light-ring and spherical photon orbit structure, or perhaps look for the presence of more exotic non-Kerr ultracompact objects. Thi","authors_text":"George Pappas, Kostas Glampedakis","cross_cats":[],"headline":"","license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","primary_cat":"gr-qc","submitted_at":"2018-06-11T16:24:50Z","title":"On the connection of spacetime separability and spherical photon orbits"},"references":{"count":0,"internal_anchors":0,"resolved_work":0,"sample":[],"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"source":{"id":"1806.04091","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:f7f21ed77a244674c8134636ab8cf073b502a8d1ada1f2938d84d41e0cea1141","target":"record","created_at":"2026-05-17T23:48:45Z","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":"ec3ec8687fabf3e70acef7f48858a9f18b22df377b38b9c3322aaefc98cf3d5d","cross_cats_sorted":[],"license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","primary_cat":"gr-qc","submitted_at":"2018-06-11T16:24:50Z","title_canon_sha256":"0f03dc7f2a678825a34de4bcddffb21f73d855619478e291f0380014c0f0d50b"},"schema_version":"1.0","source":{"id":"1806.04091","kind":"arxiv","version":2}},"canonical_sha256":"e2926fe45d9416a608e319af251bb816345e5b2ae563b409f9c8e2d88bbf9b20","receipt":{"algorithm":"ed25519","builder_version":"pith-number-builder-2026-05-17-v1","canonical_sha256":"e2926fe45d9416a608e319af251bb816345e5b2ae563b409f9c8e2d88bbf9b20","first_computed_at":"2026-05-17T23:48:45.789840Z","key_id":"pith-v1-2026-05","kind":"pith_receipt","last_reissued_at":"2026-05-17T23:48:45.789840Z","public_key_fingerprint":"8d4b5ee74e4693bcd1df2446408b0d54","receipt_version":"0.3","signature_b64":"+WE2yxZq7BAcoeBFmrBLpLPHgkEva6W9uHZstrYn0L6ysdoAMPZXfHrZn41CyztFZ4KMyECucCDZ45lZDUQ6DA==","signature_status":"signed_v1","signed_at":"2026-05-17T23:48:45.790494Z","signed_message":"canonical_sha256_bytes"},"source_id":"1806.04091","source_kind":"arxiv","source_version":2}}},"equivocations":[],"invalid_events":[],"applied_event_ids":["sha256:f7f21ed77a244674c8134636ab8cf073b502a8d1ada1f2938d84d41e0cea1141","sha256:9266544ca5dc506edf399f00fda4d7864ed02bcb613b868fde41a383d89d048e"],"state_sha256":"e9607cd81bbf2521a2a8232be6dea85a4537a5db426dfa8ea9b132d75e18cbe4"},"bundle_signature":{"signature_status":"signed_v1","algorithm":"ed25519","key_id":"pith-v1-2026-05","public_key_fingerprint":"8d4b5ee74e4693bcd1df2446408b0d54","signature_b64":"Ay1+ABszp2RHhnxhU9Ps+h6r2i+1cLwj2cuq9TJnp9yiXuOZ/fEleoUeo6uq/JHAD0aXKeKfkLjgoJQ0Al50Bw==","signed_message":"bundle_sha256_bytes","signed_at":"2026-05-25T10:58:42.556996Z","bundle_sha256":"30169c4b1e116572752546588125317edfebadfd3e10b9b6812db77dced402ce"}}