{"bundle_type":"pith_open_graph_bundle","bundle_version":"1.0","pith_number":"pith:2019:WWSGZWSMV4LXYXYQ5PBO3NF5EY","short_pith_number":"pith:WWSGZWSM","canonical_record":{"source":{"id":"1902.03875","kind":"arxiv","version":1},"metadata":{"license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","primary_cat":"astro-ph.IM","submitted_at":"2019-02-11T13:55:00Z","cross_cats_sorted":[],"title_canon_sha256":"3a7578475e7c589dfcaa405fe64a4dd71bbbb67a5c63c7ad3e9e43a6ab36e10e","abstract_canon_sha256":"c5fd3bdec6a01c661f0b1d08a561628ca16af95e1a31aef3e339102a55e22123"},"schema_version":"1.0"},"canonical_sha256":"b5a46cda4caf177c5f10ebc2edb4bd26218c6fb1939a7559f322f119ba01e19d","source":{"kind":"arxiv","id":"1902.03875","version":1},"source_aliases":[{"alias_kind":"arxiv","alias_value":"1902.03875","created_at":"2026-05-17T23:48:50Z"},{"alias_kind":"arxiv_version","alias_value":"1902.03875v1","created_at":"2026-05-17T23:48:50Z"},{"alias_kind":"doi","alias_value":"10.48550/arxiv.1902.03875","created_at":"2026-05-17T23:48:50Z"},{"alias_kind":"pith_short_12","alias_value":"WWSGZWSMV4LX","created_at":"2026-05-18T12:33:33Z"},{"alias_kind":"pith_short_16","alias_value":"WWSGZWSMV4LXYXYQ","created_at":"2026-05-18T12:33:33Z"},{"alias_kind":"pith_short_8","alias_value":"WWSGZWSM","created_at":"2026-05-18T12:33:33Z"}],"events":[{"event_type":"record_created","subject_pith_number":"pith:2019:WWSGZWSMV4LXYXYQ5PBO3NF5EY","target":"record","payload":{"canonical_record":{"source":{"id":"1902.03875","kind":"arxiv","version":1},"metadata":{"license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","primary_cat":"astro-ph.IM","submitted_at":"2019-02-11T13:55:00Z","cross_cats_sorted":[],"title_canon_sha256":"3a7578475e7c589dfcaa405fe64a4dd71bbbb67a5c63c7ad3e9e43a6ab36e10e","abstract_canon_sha256":"c5fd3bdec6a01c661f0b1d08a561628ca16af95e1a31aef3e339102a55e22123"},"schema_version":"1.0"},"canonical_sha256":"b5a46cda4caf177c5f10ebc2edb4bd26218c6fb1939a7559f322f119ba01e19d","receipt":{"kind":"pith_receipt","key_id":"pith-v1-2026-05","algorithm":"ed25519","signed_at":"2026-05-17T23:48:50.149091Z","signature_b64":"QG2/7kNHkzoIuHqDkOdp1g4Y4V3LAxOyVRVOQhRM6iNdaAPCEEAyIZEPa5xMOXbpOOyq/s/ZL6zGWly3NGmHAQ==","signed_message":"canonical_sha256_bytes","builder_version":"pith-number-builder-2026-05-17-v1","receipt_version":"0.3","canonical_sha256":"b5a46cda4caf177c5f10ebc2edb4bd26218c6fb1939a7559f322f119ba01e19d","last_reissued_at":"2026-05-17T23:48:50.148457Z","signature_status":"signed_v1","first_computed_at":"2026-05-17T23:48:50.148457Z","public_key_fingerprint":"8d4b5ee74e4693bcd1df2446408b0d54"},"source_kind":"arxiv","source_id":"1902.03875","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":"2026-05-17T23:48:50Z","supersedes":[],"prev_event":null,"signature":{"signature_status":"signed_v1","algorithm":"ed25519","key_id":"pith-v1-2026-05","public_key_fingerprint":"8d4b5ee74e4693bcd1df2446408b0d54","signature_b64":"SuvoUinfYZ40XiTqr2Kd7naaXbtZ42MUt1LigVQbxMtQap5/J2Vhw7wrsZqIfbNtwJ89rqOdgodpVzkbplxiAg==","signed_message":"open_graph_event_sha256_bytes","signed_at":"2026-08-20T20:59:15.203261Z"},"content_sha256":"a39a0c7683d8e8c2702b864e1d13b014d943bf5e534360de3ff1cf933b6f60a1","schema_version":"1.0","event_id":"sha256:a39a0c7683d8e8c2702b864e1d13b014d943bf5e534360de3ff1cf933b6f60a1"},{"event_type":"graph_snapshot","subject_pith_number":"pith:2019:WWSGZWSMV4LXYXYQ5PBO3NF5EY","target":"graph","payload":{"graph_snapshot":{"paper":{"title":"Zenith angle dependence of the cosmic ray rate as measured with Imaging air-Cherenkov Telescopes","license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","headline":"","cross_cats":[],"primary_cat":"astro-ph.IM","authors_text":"Thomas Bretz","submitted_at":"2019-02-11T13:55:00Z","abstract_excerpt":"The rate of extensive air-showers observed with imaging air-Cherenkov telescopes is zenith angle dependent. This effect originates from the increasing geometrical distance of the observed shower to the telescope with increasing zenith distance. This paper investigates how this alters the observed image and how this affects the trigger rate as a function of zenith angle. The discussed effects include the change of Cherenkov light yield, of absorption in the atmosphere, of photon density at the aperture and of the image size at the focal plane of the telescope. Based on a simple model for the at"},"claims":{"count":0,"items":[],"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"source":{"id":"1902.03875","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":"2026-05-17T23:48:50Z","supersedes":[],"prev_event":null,"signature":{"signature_status":"signed_v1","algorithm":"ed25519","key_id":"pith-v1-2026-05","public_key_fingerprint":"8d4b5ee74e4693bcd1df2446408b0d54","signature_b64":"HmTrL8zj10ZbpdGaeg9C+Ci0hqHbRI2PNNu7g4RWlFlB1dUyDuqKzLAu7wAOCm9HQNk39wwzuRr0XV92B6I/AQ==","signed_message":"open_graph_event_sha256_bytes","signed_at":"2026-08-20T20:59:15.203801Z"},"content_sha256":"68c5ac648e7812a9e1e3bf43db0079d6a197b539d134326738942ab577602d06","schema_version":"1.0","event_id":"sha256:68c5ac648e7812a9e1e3bf43db0079d6a197b539d134326738942ab577602d06"}],"timestamp_proofs":[],"mirror_hints":[{"mirror_type":"https","name":"Pith Resolver","base_url":"https://pith.science","bundle_url":"https://pith.science/pith/WWSGZWSMV4LXYXYQ5PBO3NF5EY/bundle.json","state_url":"https://pith.science/pith/WWSGZWSMV4LXYXYQ5PBO3NF5EY/state.json","well_known_bundle_url":"https://pith.science/.well-known/pith/WWSGZWSMV4LXYXYQ5PBO3NF5EY/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":"2026-08-20T20:59:15Z","links":{"resolver":"https://pith.science/pith/WWSGZWSMV4LXYXYQ5PBO3NF5EY","bundle":"https://pith.science/pith/WWSGZWSMV4LXYXYQ5PBO3NF5EY/bundle.json","state":"https://pith.science/pith/WWSGZWSMV4LXYXYQ5PBO3NF5EY/state.json","well_known_bundle":"https://pith.science/.well-known/pith/WWSGZWSMV4LXYXYQ5PBO3NF5EY/bundle.json"},"state":{"state_type":"pith_open_graph_state","state_version":"1.0","pith_number":"pith:2019:WWSGZWSMV4LXYXYQ5PBO3NF5EY","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":"c5fd3bdec6a01c661f0b1d08a561628ca16af95e1a31aef3e339102a55e22123","cross_cats_sorted":[],"license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","primary_cat":"astro-ph.IM","submitted_at":"2019-02-11T13:55:00Z","title_canon_sha256":"3a7578475e7c589dfcaa405fe64a4dd71bbbb67a5c63c7ad3e9e43a6ab36e10e"},"schema_version":"1.0","source":{"id":"1902.03875","kind":"arxiv","version":1}},"source_aliases":[{"alias_kind":"arxiv","alias_value":"1902.03875","created_at":"2026-05-17T23:48:50Z"},{"alias_kind":"arxiv_version","alias_value":"1902.03875v1","created_at":"2026-05-17T23:48:50Z"},{"alias_kind":"doi","alias_value":"10.48550/arxiv.1902.03875","created_at":"2026-05-17T23:48:50Z"},{"alias_kind":"pith_short_12","alias_value":"WWSGZWSMV4LX","created_at":"2026-05-18T12:33:33Z"},{"alias_kind":"pith_short_16","alias_value":"WWSGZWSMV4LXYXYQ","created_at":"2026-05-18T12:33:33Z"},{"alias_kind":"pith_short_8","alias_value":"WWSGZWSM","created_at":"2026-05-18T12:33:33Z"}],"graph_snapshots":[{"event_id":"sha256:68c5ac648e7812a9e1e3bf43db0079d6a197b539d134326738942ab577602d06","target":"graph","created_at":"2026-05-17T23:48:50Z","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 rate of extensive air-showers observed with imaging air-Cherenkov telescopes is zenith angle dependent. This effect originates from the increasing geometrical distance of the observed shower to the telescope with increasing zenith distance. This paper investigates how this alters the observed image and how this affects the trigger rate as a function of zenith angle. The discussed effects include the change of Cherenkov light yield, of absorption in the atmosphere, of photon density at the aperture and of the image size at the focal plane of the telescope. Based on a simple model for the at","authors_text":"Thomas Bretz","cross_cats":[],"headline":"","license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","primary_cat":"astro-ph.IM","submitted_at":"2019-02-11T13:55:00Z","title":"Zenith angle dependence of the cosmic ray rate as measured with Imaging air-Cherenkov Telescopes"},"references":{"count":0,"internal_anchors":0,"resolved_work":0,"sample":[],"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"source":{"id":"1902.03875","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:a39a0c7683d8e8c2702b864e1d13b014d943bf5e534360de3ff1cf933b6f60a1","target":"record","created_at":"2026-05-17T23:48:50Z","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":"c5fd3bdec6a01c661f0b1d08a561628ca16af95e1a31aef3e339102a55e22123","cross_cats_sorted":[],"license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","primary_cat":"astro-ph.IM","submitted_at":"2019-02-11T13:55:00Z","title_canon_sha256":"3a7578475e7c589dfcaa405fe64a4dd71bbbb67a5c63c7ad3e9e43a6ab36e10e"},"schema_version":"1.0","source":{"id":"1902.03875","kind":"arxiv","version":1}},"canonical_sha256":"b5a46cda4caf177c5f10ebc2edb4bd26218c6fb1939a7559f322f119ba01e19d","receipt":{"algorithm":"ed25519","builder_version":"pith-number-builder-2026-05-17-v1","canonical_sha256":"b5a46cda4caf177c5f10ebc2edb4bd26218c6fb1939a7559f322f119ba01e19d","first_computed_at":"2026-05-17T23:48:50.148457Z","key_id":"pith-v1-2026-05","kind":"pith_receipt","last_reissued_at":"2026-05-17T23:48:50.148457Z","public_key_fingerprint":"8d4b5ee74e4693bcd1df2446408b0d54","receipt_version":"0.3","signature_b64":"QG2/7kNHkzoIuHqDkOdp1g4Y4V3LAxOyVRVOQhRM6iNdaAPCEEAyIZEPa5xMOXbpOOyq/s/ZL6zGWly3NGmHAQ==","signature_status":"signed_v1","signed_at":"2026-05-17T23:48:50.149091Z","signed_message":"canonical_sha256_bytes"},"source_id":"1902.03875","source_kind":"arxiv","source_version":1}}},"equivocations":[],"invalid_events":[],"applied_event_ids":["sha256:a39a0c7683d8e8c2702b864e1d13b014d943bf5e534360de3ff1cf933b6f60a1","sha256:68c5ac648e7812a9e1e3bf43db0079d6a197b539d134326738942ab577602d06"],"state_sha256":"1de51c27776c823aa634faa7f061f18c7b1fd8d3a574e5474eb47e68c15d9977"},"bundle_signature":{"signature_status":"signed_v1","algorithm":"ed25519","key_id":"pith-v1-2026-05","public_key_fingerprint":"8d4b5ee74e4693bcd1df2446408b0d54","signature_b64":"B+mg4EBQex8uNcSz+0NXCQMBHCDp/asYvxcBJDVpumLwFpwa1ybjHpA92Eq/k9k/0dvdgSblzmr2mO7YE/sDCA==","signed_message":"bundle_sha256_bytes","signed_at":"2026-08-20T20:59:15.210187Z","bundle_sha256":"9ee587bc89f5169a997e0ea73b60d32f9ada4f1745562d642b599382e83c385d"}}