{"bundle_type":"pith_open_graph_bundle","bundle_version":"1.0","pith_number":"pith:2013:TFQUKCDOPM7QSW3ZTBK6F4R6QZ","short_pith_number":"pith:TFQUKCDO","canonical_record":{"source":{"id":"1309.3846","kind":"arxiv","version":1},"metadata":{"license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","primary_cat":"astro-ph.HE","submitted_at":"2013-09-16T08:08:39Z","cross_cats_sorted":["hep-ph"],"title_canon_sha256":"1647c7481a83525b43e492cf8ae87deaa0117d571bb715402800890b445d463c","abstract_canon_sha256":"df52893732567970b8788b8001a73668c9d3af79311c1c8d0163ae6b49cc85a5"},"schema_version":"1.0"},"canonical_sha256":"996145086e7b3f095b799855e2f23e867ef0d3acd07edf505e130498c717dc4c","source":{"kind":"arxiv","id":"1309.3846","version":1},"source_aliases":[{"alias_kind":"arxiv","alias_value":"1309.3846","created_at":"2026-05-18T03:13:12Z"},{"alias_kind":"arxiv_version","alias_value":"1309.3846v1","created_at":"2026-05-18T03:13:12Z"},{"alias_kind":"doi","alias_value":"10.48550/arxiv.1309.3846","created_at":"2026-05-18T03:13:12Z"},{"alias_kind":"pith_short_12","alias_value":"TFQUKCDOPM7Q","created_at":"2026-05-18T12:28:02Z"},{"alias_kind":"pith_short_16","alias_value":"TFQUKCDOPM7QSW3Z","created_at":"2026-05-18T12:28:02Z"},{"alias_kind":"pith_short_8","alias_value":"TFQUKCDO","created_at":"2026-05-18T12:28:02Z"}],"events":[{"event_type":"record_created","subject_pith_number":"pith:2013:TFQUKCDOPM7QSW3ZTBK6F4R6QZ","target":"record","payload":{"canonical_record":{"source":{"id":"1309.3846","kind":"arxiv","version":1},"metadata":{"license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","primary_cat":"astro-ph.HE","submitted_at":"2013-09-16T08:08:39Z","cross_cats_sorted":["hep-ph"],"title_canon_sha256":"1647c7481a83525b43e492cf8ae87deaa0117d571bb715402800890b445d463c","abstract_canon_sha256":"df52893732567970b8788b8001a73668c9d3af79311c1c8d0163ae6b49cc85a5"},"schema_version":"1.0"},"canonical_sha256":"996145086e7b3f095b799855e2f23e867ef0d3acd07edf505e130498c717dc4c","receipt":{"kind":"pith_receipt","key_id":"pith-v1-2026-05","algorithm":"ed25519","signed_at":"2026-05-18T03:13:12.221450Z","signature_b64":"dyrd6KBBBeZ1cSMvWE8DUTwwCVlRxRvdw7Hik5MDSDjX5LjoDqZpOv1Wi1vAvkkJCC6yMbRx9rJDwp/23TTFDQ==","signed_message":"canonical_sha256_bytes","builder_version":"pith-number-builder-2026-05-17-v1","receipt_version":"0.3","canonical_sha256":"996145086e7b3f095b799855e2f23e867ef0d3acd07edf505e130498c717dc4c","last_reissued_at":"2026-05-18T03:13:12.220846Z","signature_status":"signed_v1","first_computed_at":"2026-05-18T03:13:12.220846Z","public_key_fingerprint":"8d4b5ee74e4693bcd1df2446408b0d54"},"source_kind":"arxiv","source_id":"1309.3846","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":"2026-05-18T03:13:12Z","supersedes":[],"prev_event":null,"signature":{"signature_status":"signed_v1","algorithm":"ed25519","key_id":"pith-v1-2026-05","public_key_fingerprint":"8d4b5ee74e4693bcd1df2446408b0d54","signature_b64":"+B3Ne4nKKoq1+d9QwQrHFXe/Dm4WqpL8P96M8lBaoKfNonQp4seP+0E57rCZfjZQeQQ8LidA94P67TEpdcqkAQ==","signed_message":"open_graph_event_sha256_bytes","signed_at":"2026-05-28T01:55:14.996007Z"},"content_sha256":"cc197873ba9d57001e45b52374d22a8b4fc7cf0dbe8fd386698d3bade498d1f7","schema_version":"1.0","event_id":"sha256:cc197873ba9d57001e45b52374d22a8b4fc7cf0dbe8fd386698d3bade498d1f7"},{"event_type":"graph_snapshot","subject_pith_number":"pith:2013:TFQUKCDOPM7QSW3ZTBK6F4R6QZ","target":"graph","payload":{"graph_snapshot":{"paper":{"title":"Pair-production opacity at high and very-high gamma-ray energies","license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","headline":"","cross_cats":["hep-ph"],"primary_cat":"astro-ph.HE","authors_text":"Dieter Horns, Manuel Meyer","submitted_at":"2013-09-16T08:08:39Z","abstract_excerpt":"The propagation of high energy (HE, $E_\\gamma>100$ MeV) and very high-energy gamma-rays (VHE, $E_\\gamma>100$ GeV) in the extra-galactic photon field leads to pair-production and consequently energy- and distance-dependent attenuation of the primary intensity. The spectroscopy of an increasing number of extra-galactic objects at HE and VHE energies has demonstrated indeed the presence of such an attenuation which in turn has been used to constrain the photon density in the medium. At large optical depth ($\\tau\\gtrsim 2$) potential modifications of pair-production due to competing but rare proce"},"claims":{"count":0,"items":[],"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"source":{"id":"1309.3846","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":""},"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":"2026-05-18T03:13:12Z","supersedes":[],"prev_event":null,"signature":{"signature_status":"signed_v1","algorithm":"ed25519","key_id":"pith-v1-2026-05","public_key_fingerprint":"8d4b5ee74e4693bcd1df2446408b0d54","signature_b64":"VfkqeVFWoVymDjtujnpq0yJoysprp1rwv5wN0/3rjzKNbgSQO/ZNFdNCVIAzD9qjPtfHQmnsUwh3WdsojsMJAA==","signed_message":"open_graph_event_sha256_bytes","signed_at":"2026-05-28T01:55:14.996635Z"},"content_sha256":"1fca467ff36c02040d0456c624e7b3d60a1615942285b7e39418db94afdc2f8d","schema_version":"1.0","event_id":"sha256:1fca467ff36c02040d0456c624e7b3d60a1615942285b7e39418db94afdc2f8d"}],"timestamp_proofs":[],"mirror_hints":[{"mirror_type":"https","name":"Pith Resolver","base_url":"https://pith.science","bundle_url":"https://pith.science/pith/TFQUKCDOPM7QSW3ZTBK6F4R6QZ/bundle.json","state_url":"https://pith.science/pith/TFQUKCDOPM7QSW3ZTBK6F4R6QZ/state.json","well_known_bundle_url":"https://pith.science/.well-known/pith/TFQUKCDOPM7QSW3ZTBK6F4R6QZ/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":"2026-05-28T01:55:14Z","links":{"resolver":"https://pith.science/pith/TFQUKCDOPM7QSW3ZTBK6F4R6QZ","bundle":"https://pith.science/pith/TFQUKCDOPM7QSW3ZTBK6F4R6QZ/bundle.json","state":"https://pith.science/pith/TFQUKCDOPM7QSW3ZTBK6F4R6QZ/state.json","well_known_bundle":"https://pith.science/.well-known/pith/TFQUKCDOPM7QSW3ZTBK6F4R6QZ/bundle.json"},"state":{"state_type":"pith_open_graph_state","state_version":"1.0","pith_number":"pith:2013:TFQUKCDOPM7QSW3ZTBK6F4R6QZ","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":"df52893732567970b8788b8001a73668c9d3af79311c1c8d0163ae6b49cc85a5","cross_cats_sorted":["hep-ph"],"license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","primary_cat":"astro-ph.HE","submitted_at":"2013-09-16T08:08:39Z","title_canon_sha256":"1647c7481a83525b43e492cf8ae87deaa0117d571bb715402800890b445d463c"},"schema_version":"1.0","source":{"id":"1309.3846","kind":"arxiv","version":1}},"source_aliases":[{"alias_kind":"arxiv","alias_value":"1309.3846","created_at":"2026-05-18T03:13:12Z"},{"alias_kind":"arxiv_version","alias_value":"1309.3846v1","created_at":"2026-05-18T03:13:12Z"},{"alias_kind":"doi","alias_value":"10.48550/arxiv.1309.3846","created_at":"2026-05-18T03:13:12Z"},{"alias_kind":"pith_short_12","alias_value":"TFQUKCDOPM7Q","created_at":"2026-05-18T12:28:02Z"},{"alias_kind":"pith_short_16","alias_value":"TFQUKCDOPM7QSW3Z","created_at":"2026-05-18T12:28:02Z"},{"alias_kind":"pith_short_8","alias_value":"TFQUKCDO","created_at":"2026-05-18T12:28:02Z"}],"graph_snapshots":[{"event_id":"sha256:1fca467ff36c02040d0456c624e7b3d60a1615942285b7e39418db94afdc2f8d","target":"graph","created_at":"2026-05-18T03:13:12Z","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 propagation of high energy (HE, $E_\\gamma>100$ MeV) and very high-energy gamma-rays (VHE, $E_\\gamma>100$ GeV) in the extra-galactic photon field leads to pair-production and consequently energy- and distance-dependent attenuation of the primary intensity. The spectroscopy of an increasing number of extra-galactic objects at HE and VHE energies has demonstrated indeed the presence of such an attenuation which in turn has been used to constrain the photon density in the medium. At large optical depth ($\\tau\\gtrsim 2$) potential modifications of pair-production due to competing but rare proce","authors_text":"Dieter Horns, Manuel Meyer","cross_cats":["hep-ph"],"headline":"","license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","primary_cat":"astro-ph.HE","submitted_at":"2013-09-16T08:08:39Z","title":"Pair-production opacity at high and very-high gamma-ray energies"},"references":{"count":0,"internal_anchors":0,"resolved_work":0,"sample":[],"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"source":{"id":"1309.3846","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:cc197873ba9d57001e45b52374d22a8b4fc7cf0dbe8fd386698d3bade498d1f7","target":"record","created_at":"2026-05-18T03:13:12Z","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":"df52893732567970b8788b8001a73668c9d3af79311c1c8d0163ae6b49cc85a5","cross_cats_sorted":["hep-ph"],"license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","primary_cat":"astro-ph.HE","submitted_at":"2013-09-16T08:08:39Z","title_canon_sha256":"1647c7481a83525b43e492cf8ae87deaa0117d571bb715402800890b445d463c"},"schema_version":"1.0","source":{"id":"1309.3846","kind":"arxiv","version":1}},"canonical_sha256":"996145086e7b3f095b799855e2f23e867ef0d3acd07edf505e130498c717dc4c","receipt":{"algorithm":"ed25519","builder_version":"pith-number-builder-2026-05-17-v1","canonical_sha256":"996145086e7b3f095b799855e2f23e867ef0d3acd07edf505e130498c717dc4c","first_computed_at":"2026-05-18T03:13:12.220846Z","key_id":"pith-v1-2026-05","kind":"pith_receipt","last_reissued_at":"2026-05-18T03:13:12.220846Z","public_key_fingerprint":"8d4b5ee74e4693bcd1df2446408b0d54","receipt_version":"0.3","signature_b64":"dyrd6KBBBeZ1cSMvWE8DUTwwCVlRxRvdw7Hik5MDSDjX5LjoDqZpOv1Wi1vAvkkJCC6yMbRx9rJDwp/23TTFDQ==","signature_status":"signed_v1","signed_at":"2026-05-18T03:13:12.221450Z","signed_message":"canonical_sha256_bytes"},"source_id":"1309.3846","source_kind":"arxiv","source_version":1}}},"equivocations":[],"invalid_events":[],"applied_event_ids":["sha256:cc197873ba9d57001e45b52374d22a8b4fc7cf0dbe8fd386698d3bade498d1f7","sha256:1fca467ff36c02040d0456c624e7b3d60a1615942285b7e39418db94afdc2f8d"],"state_sha256":"722e0c3a49326ad64736010749e42b7cf703c0f1abd08ce1932e2397528a9b9e"},"bundle_signature":{"signature_status":"signed_v1","algorithm":"ed25519","key_id":"pith-v1-2026-05","public_key_fingerprint":"8d4b5ee74e4693bcd1df2446408b0d54","signature_b64":"gLdUBvVjaf+kbcl2ZlXAYYbzsUvn/yeBP35aFKErhvkqpOs0HDbG5q/a2JP/3wF7TZCW8s3hVniR5agXV57KDQ==","signed_message":"bundle_sha256_bytes","signed_at":"2026-05-28T01:55:14.999613Z","bundle_sha256":"c43f4dbe9b0ee9f60c57d9ac75667a99c17c600e323a98c27d4128ae558474c8"}}