{"bundle_type":"pith_open_graph_bundle","bundle_version":"1.0","pith_number":"pith:2016:6AI4UBBWC5XMVHV3UNB7LEQCD2","short_pith_number":"pith:6AI4UBBW","canonical_record":{"source":{"id":"1605.05774","kind":"arxiv","version":3},"metadata":{"license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","primary_cat":"gr-qc","submitted_at":"2016-05-18T22:13:57Z","cross_cats_sorted":["hep-th"],"title_canon_sha256":"a9f14b7d50a510a85b3ec8ffda41b89fb929d69116aa90419b7619a656620fe4","abstract_canon_sha256":"79f069d435ae487a8e3e8c904c0df9199fb3bb43a3376f4f15892c63460a4b29"},"schema_version":"1.0"},"canonical_sha256":"f011ca0436176eca9ebba343f592021ebba5cfd1fdedabd98e3e1310fb85ca07","source":{"kind":"arxiv","id":"1605.05774","version":3},"source_aliases":[{"alias_kind":"arxiv","alias_value":"1605.05774","created_at":"2026-05-18T00:39:18Z"},{"alias_kind":"arxiv_version","alias_value":"1605.05774v3","created_at":"2026-05-18T00:39:18Z"},{"alias_kind":"doi","alias_value":"10.48550/arxiv.1605.05774","created_at":"2026-05-18T00:39:18Z"},{"alias_kind":"pith_short_12","alias_value":"6AI4UBBWC5XM","created_at":"2026-05-18T12:30:01Z"},{"alias_kind":"pith_short_16","alias_value":"6AI4UBBWC5XMVHV3","created_at":"2026-05-18T12:30:01Z"},{"alias_kind":"pith_short_8","alias_value":"6AI4UBBW","created_at":"2026-05-18T12:30:01Z"}],"events":[{"event_type":"record_created","subject_pith_number":"pith:2016:6AI4UBBWC5XMVHV3UNB7LEQCD2","target":"record","payload":{"canonical_record":{"source":{"id":"1605.05774","kind":"arxiv","version":3},"metadata":{"license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","primary_cat":"gr-qc","submitted_at":"2016-05-18T22:13:57Z","cross_cats_sorted":["hep-th"],"title_canon_sha256":"a9f14b7d50a510a85b3ec8ffda41b89fb929d69116aa90419b7619a656620fe4","abstract_canon_sha256":"79f069d435ae487a8e3e8c904c0df9199fb3bb43a3376f4f15892c63460a4b29"},"schema_version":"1.0"},"canonical_sha256":"f011ca0436176eca9ebba343f592021ebba5cfd1fdedabd98e3e1310fb85ca07","receipt":{"kind":"pith_receipt","key_id":"pith-v1-2026-05","algorithm":"ed25519","signed_at":"2026-05-18T00:39:18.392970Z","signature_b64":"Zi4kpdxdipaQVG/re4PYspYv+x7pTQLX7KOgvnSMJ/PyGuSL/9uylm+NAJGdbTavDwyJ5uBH1R9F+NfIbWlHDw==","signed_message":"canonical_sha256_bytes","builder_version":"pith-number-builder-2026-05-17-v1","receipt_version":"0.3","canonical_sha256":"f011ca0436176eca9ebba343f592021ebba5cfd1fdedabd98e3e1310fb85ca07","last_reissued_at":"2026-05-18T00:39:18.392284Z","signature_status":"signed_v1","first_computed_at":"2026-05-18T00:39:18.392284Z","public_key_fingerprint":"8d4b5ee74e4693bcd1df2446408b0d54"},"source_kind":"arxiv","source_id":"1605.05774","source_version":3,"attestation_state":"computed"},"signer":{"signer_id":"pith.science","signer_type":"pith_registry","key_id":"pith-v1-2026-05","public_key_fingerprint":"8d4b5ee74e4693bcd1df2446408b0d54"},"created_at":"2026-05-18T00:39:18Z","supersedes":[],"prev_event":null,"signature":{"signature_status":"signed_v1","algorithm":"ed25519","key_id":"pith-v1-2026-05","public_key_fingerprint":"8d4b5ee74e4693bcd1df2446408b0d54","signature_b64":"lGIjOP2zPD9bJ2iukn/87SQAHFW1byWvzShFAGqsS5LpcxOmq4qSO6Lo+TRimi2sheAHIDE5r3QGdNGA3l7OCw==","signed_message":"open_graph_event_sha256_bytes","signed_at":"2026-08-05T00:23:35.159969Z"},"content_sha256":"f7a1f14b78290aa30fa8181602266b5dc98d48502d9a73e335c584b1ebbe836b","schema_version":"1.0","event_id":"sha256:f7a1f14b78290aa30fa8181602266b5dc98d48502d9a73e335c584b1ebbe836b"},{"event_type":"graph_snapshot","subject_pith_number":"pith:2016:6AI4UBBWC5XMVHV3UNB7LEQCD2","target":"graph","payload":{"graph_snapshot":{"paper":{"title":"Lux in obscuro: Photon Orbits of Extremal Black Holes Revisited","license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","headline":"","cross_cats":["hep-th"],"primary_cat":"gr-qc","authors_text":"Fech Scen Khoo, Yen Chin Ong","submitted_at":"2016-05-18T22:13:57Z","abstract_excerpt":"It has been shown in the literature that the event horizon of an extremal asymptotically flat Reissner-Nordstrom black hole is also a stable photon sphere. We further clarify this statement and give a general proof that this holds for a large class of static spherically symmetric black hole spacetimes with an extremal horizon. In contrast, in the Doran frame, an extremal asymptotically flat Kerr black hole has an unstable photon orbit on the equatorial plane of its horizon. In addition, we show that an extremal asymptotically flat Kerr-Newman black hole exhibits two equatorial photon orbits if"},"claims":{"count":0,"items":[],"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"source":{"id":"1605.05774","kind":"arxiv","version":3},"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":"2026-05-18T00:39:18Z","supersedes":[],"prev_event":null,"signature":{"signature_status":"signed_v1","algorithm":"ed25519","key_id":"pith-v1-2026-05","public_key_fingerprint":"8d4b5ee74e4693bcd1df2446408b0d54","signature_b64":"xJKMfK0QBAKIhKpGq7x5/i+/NrsTqtE7EpE6UjhHYvdma/nomNZBNSY2/EoZJVxfnzbFLREdXA4Or2rQSkd4Cw==","signed_message":"open_graph_event_sha256_bytes","signed_at":"2026-08-05T00:23:35.160906Z"},"content_sha256":"1769551b3c1e4184a5eac03eafbe7aab6d65f5b1c438d6ddb55f563871a70e5b","schema_version":"1.0","event_id":"sha256:1769551b3c1e4184a5eac03eafbe7aab6d65f5b1c438d6ddb55f563871a70e5b"}],"timestamp_proofs":[],"mirror_hints":[{"mirror_type":"https","name":"Pith Resolver","base_url":"https://pith.science","bundle_url":"https://pith.science/pith/6AI4UBBWC5XMVHV3UNB7LEQCD2/bundle.json","state_url":"https://pith.science/pith/6AI4UBBWC5XMVHV3UNB7LEQCD2/state.json","well_known_bundle_url":"https://pith.science/.well-known/pith/6AI4UBBWC5XMVHV3UNB7LEQCD2/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":"2026-08-05T00:23:35Z","links":{"resolver":"https://pith.science/pith/6AI4UBBWC5XMVHV3UNB7LEQCD2","bundle":"https://pith.science/pith/6AI4UBBWC5XMVHV3UNB7LEQCD2/bundle.json","state":"https://pith.science/pith/6AI4UBBWC5XMVHV3UNB7LEQCD2/state.json","well_known_bundle":"https://pith.science/.well-known/pith/6AI4UBBWC5XMVHV3UNB7LEQCD2/bundle.json"},"state":{"state_type":"pith_open_graph_state","state_version":"1.0","pith_number":"pith:2016:6AI4UBBWC5XMVHV3UNB7LEQCD2","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":"79f069d435ae487a8e3e8c904c0df9199fb3bb43a3376f4f15892c63460a4b29","cross_cats_sorted":["hep-th"],"license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","primary_cat":"gr-qc","submitted_at":"2016-05-18T22:13:57Z","title_canon_sha256":"a9f14b7d50a510a85b3ec8ffda41b89fb929d69116aa90419b7619a656620fe4"},"schema_version":"1.0","source":{"id":"1605.05774","kind":"arxiv","version":3}},"source_aliases":[{"alias_kind":"arxiv","alias_value":"1605.05774","created_at":"2026-05-18T00:39:18Z"},{"alias_kind":"arxiv_version","alias_value":"1605.05774v3","created_at":"2026-05-18T00:39:18Z"},{"alias_kind":"doi","alias_value":"10.48550/arxiv.1605.05774","created_at":"2026-05-18T00:39:18Z"},{"alias_kind":"pith_short_12","alias_value":"6AI4UBBWC5XM","created_at":"2026-05-18T12:30:01Z"},{"alias_kind":"pith_short_16","alias_value":"6AI4UBBWC5XMVHV3","created_at":"2026-05-18T12:30:01Z"},{"alias_kind":"pith_short_8","alias_value":"6AI4UBBW","created_at":"2026-05-18T12:30:01Z"}],"graph_snapshots":[{"event_id":"sha256:1769551b3c1e4184a5eac03eafbe7aab6d65f5b1c438d6ddb55f563871a70e5b","target":"graph","created_at":"2026-05-18T00:39:18Z","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":"It has been shown in the literature that the event horizon of an extremal asymptotically flat Reissner-Nordstrom black hole is also a stable photon sphere. We further clarify this statement and give a general proof that this holds for a large class of static spherically symmetric black hole spacetimes with an extremal horizon. In contrast, in the Doran frame, an extremal asymptotically flat Kerr black hole has an unstable photon orbit on the equatorial plane of its horizon. In addition, we show that an extremal asymptotically flat Kerr-Newman black hole exhibits two equatorial photon orbits if","authors_text":"Fech Scen Khoo, Yen Chin Ong","cross_cats":["hep-th"],"headline":"","license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","primary_cat":"gr-qc","submitted_at":"2016-05-18T22:13:57Z","title":"Lux in obscuro: Photon Orbits of Extremal Black Holes Revisited"},"references":{"count":0,"internal_anchors":0,"resolved_work":0,"sample":[],"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"source":{"id":"1605.05774","kind":"arxiv","version":3},"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:f7a1f14b78290aa30fa8181602266b5dc98d48502d9a73e335c584b1ebbe836b","target":"record","created_at":"2026-05-18T00:39:18Z","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":"79f069d435ae487a8e3e8c904c0df9199fb3bb43a3376f4f15892c63460a4b29","cross_cats_sorted":["hep-th"],"license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","primary_cat":"gr-qc","submitted_at":"2016-05-18T22:13:57Z","title_canon_sha256":"a9f14b7d50a510a85b3ec8ffda41b89fb929d69116aa90419b7619a656620fe4"},"schema_version":"1.0","source":{"id":"1605.05774","kind":"arxiv","version":3}},"canonical_sha256":"f011ca0436176eca9ebba343f592021ebba5cfd1fdedabd98e3e1310fb85ca07","receipt":{"algorithm":"ed25519","builder_version":"pith-number-builder-2026-05-17-v1","canonical_sha256":"f011ca0436176eca9ebba343f592021ebba5cfd1fdedabd98e3e1310fb85ca07","first_computed_at":"2026-05-18T00:39:18.392284Z","key_id":"pith-v1-2026-05","kind":"pith_receipt","last_reissued_at":"2026-05-18T00:39:18.392284Z","public_key_fingerprint":"8d4b5ee74e4693bcd1df2446408b0d54","receipt_version":"0.3","signature_b64":"Zi4kpdxdipaQVG/re4PYspYv+x7pTQLX7KOgvnSMJ/PyGuSL/9uylm+NAJGdbTavDwyJ5uBH1R9F+NfIbWlHDw==","signature_status":"signed_v1","signed_at":"2026-05-18T00:39:18.392970Z","signed_message":"canonical_sha256_bytes"},"source_id":"1605.05774","source_kind":"arxiv","source_version":3}}},"equivocations":[],"invalid_events":[],"applied_event_ids":["sha256:f7a1f14b78290aa30fa8181602266b5dc98d48502d9a73e335c584b1ebbe836b","sha256:1769551b3c1e4184a5eac03eafbe7aab6d65f5b1c438d6ddb55f563871a70e5b"],"state_sha256":"92c80a1815d0b86d5fd46641acb2ea0e2c470ed13446151b5388a5cbc3fdd46c"},"bundle_signature":{"signature_status":"signed_v1","algorithm":"ed25519","key_id":"pith-v1-2026-05","public_key_fingerprint":"8d4b5ee74e4693bcd1df2446408b0d54","signature_b64":"Xc7+qqy9mC73Ls1L30vhU3shziz4Ohvkfiocyoywu5FAvVLieEkKEm5uN73K1EZUWTK0Utq6eXoo3y8dTs5sCg==","signed_message":"bundle_sha256_bytes","signed_at":"2026-08-05T00:23:35.167806Z","bundle_sha256":"503bcc9146d8629d1005575cc0faf413279a1b868fd5a5f01634eb22ff3cb63c"}}