{"bundle_type":"pith_open_graph_bundle","bundle_version":"1.0","pith_number":"pith:2018:MYITBZXK46YHSDULDFK4O2UVBM","short_pith_number":"pith:MYITBZXK","canonical_record":{"source":{"id":"1802.01364","kind":"arxiv","version":1},"metadata":{"license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","primary_cat":"astro-ph.GA","submitted_at":"2018-02-05T12:22:24Z","cross_cats_sorted":["astro-ph.EP"],"title_canon_sha256":"39a44ab23cad5c7eed7bec79c4a756de024f901b431a5cbce553ffab26395da6","abstract_canon_sha256":"555bb1537fe836995aa67c6a4746b8d2dddb3936eaa6cc997d0c7952fff77f0e"},"schema_version":"1.0"},"canonical_sha256":"661130e6eae7b0790e8b1955c76a950b1985f095e3add8f79d836a709f44d075","source":{"kind":"arxiv","id":"1802.01364","version":1},"source_aliases":[{"alias_kind":"arxiv","alias_value":"1802.01364","created_at":"2026-05-18T00:22:22Z"},{"alias_kind":"arxiv_version","alias_value":"1802.01364v1","created_at":"2026-05-18T00:22:22Z"},{"alias_kind":"doi","alias_value":"10.48550/arxiv.1802.01364","created_at":"2026-05-18T00:22:22Z"},{"alias_kind":"pith_short_12","alias_value":"MYITBZXK46YH","created_at":"2026-05-18T12:32:40Z"},{"alias_kind":"pith_short_16","alias_value":"MYITBZXK46YHSDUL","created_at":"2026-05-18T12:32:40Z"},{"alias_kind":"pith_short_8","alias_value":"MYITBZXK","created_at":"2026-05-18T12:32:40Z"}],"events":[{"event_type":"record_created","subject_pith_number":"pith:2018:MYITBZXK46YHSDULDFK4O2UVBM","target":"record","payload":{"canonical_record":{"source":{"id":"1802.01364","kind":"arxiv","version":1},"metadata":{"license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","primary_cat":"astro-ph.GA","submitted_at":"2018-02-05T12:22:24Z","cross_cats_sorted":["astro-ph.EP"],"title_canon_sha256":"39a44ab23cad5c7eed7bec79c4a756de024f901b431a5cbce553ffab26395da6","abstract_canon_sha256":"555bb1537fe836995aa67c6a4746b8d2dddb3936eaa6cc997d0c7952fff77f0e"},"schema_version":"1.0"},"canonical_sha256":"661130e6eae7b0790e8b1955c76a950b1985f095e3add8f79d836a709f44d075","receipt":{"kind":"pith_receipt","key_id":"pith-v1-2026-05","algorithm":"ed25519","signed_at":"2026-05-18T00:22:22.695223Z","signature_b64":"3G7WAnJhscrWRS/pz0XQZZJvZKFU6LIxwaFH0CCGElrWZEo1k17bd/q1d73U0Uu9k5L5EYQ4JM14ES0pifvcBw==","signed_message":"canonical_sha256_bytes","builder_version":"pith-number-builder-2026-05-17-v1","receipt_version":"0.3","canonical_sha256":"661130e6eae7b0790e8b1955c76a950b1985f095e3add8f79d836a709f44d075","last_reissued_at":"2026-05-18T00:22:22.694712Z","signature_status":"signed_v1","first_computed_at":"2026-05-18T00:22:22.694712Z","public_key_fingerprint":"8d4b5ee74e4693bcd1df2446408b0d54"},"source_kind":"arxiv","source_id":"1802.01364","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":"2026-05-18T00:22:22Z","supersedes":[],"prev_event":null,"signature":{"signature_status":"signed_v1","algorithm":"ed25519","key_id":"pith-v1-2026-05","public_key_fingerprint":"8d4b5ee74e4693bcd1df2446408b0d54","signature_b64":"VTekf/IfduYF8H4FSoFhH5N/kHtqwvonvaczvlul6ZSFM8ml2QI4oYy+h6SUaTDXDzRikdwAc7MV41eEdSRLBg==","signed_message":"open_graph_event_sha256_bytes","signed_at":"2026-05-23T09:34:11.492967Z"},"content_sha256":"b3d7c2d7dbd4759c389c2f40144000bc75d7c0f3c8a589f308e26ed47df3872a","schema_version":"1.0","event_id":"sha256:b3d7c2d7dbd4759c389c2f40144000bc75d7c0f3c8a589f308e26ed47df3872a"},{"event_type":"graph_snapshot","subject_pith_number":"pith:2018:MYITBZXK46YHSDULDFK4O2UVBM","target":"graph","payload":{"graph_snapshot":{"paper":{"title":"Classifying and modelling spiral structures in hydrodynamic simulations of astrophysical discs","license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","headline":"","cross_cats":["astro-ph.EP"],"primary_cat":"astro-ph.GA","authors_text":"D.H. Forgan, F.G. Ram\\'on-Fox, I.A. Bonnell","submitted_at":"2018-02-05T12:22:24Z","abstract_excerpt":"We demonstrate numerical techniques for automatic identification of individual spiral arms in hydrodynamic simulations of astrophysical discs. Building on our earlier work, which used tensor classification to identify regions that were \"spiral-like\", we can now obtain fits to spirals for individual arm elements. We show this process can even detect spirals in relatively flocculent spiral patterns, but the resulting fits to logarithmic \"grand-design\" spirals are less robust. Our methods not only permit the estimation of pitch angles, but also direct measurements of the spiral arm width and patt"},"claims":{"count":0,"items":[],"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"source":{"id":"1802.01364","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":"2026-05-18T00:22:22Z","supersedes":[],"prev_event":null,"signature":{"signature_status":"signed_v1","algorithm":"ed25519","key_id":"pith-v1-2026-05","public_key_fingerprint":"8d4b5ee74e4693bcd1df2446408b0d54","signature_b64":"eKOcu673CiIvV14p3plAx6IO8s/9JG4dav4lTCG+bgU5aE0eKmxf67PQ0Kq6ZjM31qXvKtStWXS4KEKEiSEeCg==","signed_message":"open_graph_event_sha256_bytes","signed_at":"2026-05-23T09:34:11.493708Z"},"content_sha256":"040b4ee7ce2a6559dd52f6689cb4710b5e6d0ec8835a9ea0afdf1d6714949f63","schema_version":"1.0","event_id":"sha256:040b4ee7ce2a6559dd52f6689cb4710b5e6d0ec8835a9ea0afdf1d6714949f63"}],"timestamp_proofs":[],"mirror_hints":[{"mirror_type":"https","name":"Pith Resolver","base_url":"https://pith.science","bundle_url":"https://pith.science/pith/MYITBZXK46YHSDULDFK4O2UVBM/bundle.json","state_url":"https://pith.science/pith/MYITBZXK46YHSDULDFK4O2UVBM/state.json","well_known_bundle_url":"https://pith.science/.well-known/pith/MYITBZXK46YHSDULDFK4O2UVBM/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":"2026-05-23T09:34:11Z","links":{"resolver":"https://pith.science/pith/MYITBZXK46YHSDULDFK4O2UVBM","bundle":"https://pith.science/pith/MYITBZXK46YHSDULDFK4O2UVBM/bundle.json","state":"https://pith.science/pith/MYITBZXK46YHSDULDFK4O2UVBM/state.json","well_known_bundle":"https://pith.science/.well-known/pith/MYITBZXK46YHSDULDFK4O2UVBM/bundle.json"},"state":{"state_type":"pith_open_graph_state","state_version":"1.0","pith_number":"pith:2018:MYITBZXK46YHSDULDFK4O2UVBM","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":"555bb1537fe836995aa67c6a4746b8d2dddb3936eaa6cc997d0c7952fff77f0e","cross_cats_sorted":["astro-ph.EP"],"license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","primary_cat":"astro-ph.GA","submitted_at":"2018-02-05T12:22:24Z","title_canon_sha256":"39a44ab23cad5c7eed7bec79c4a756de024f901b431a5cbce553ffab26395da6"},"schema_version":"1.0","source":{"id":"1802.01364","kind":"arxiv","version":1}},"source_aliases":[{"alias_kind":"arxiv","alias_value":"1802.01364","created_at":"2026-05-18T00:22:22Z"},{"alias_kind":"arxiv_version","alias_value":"1802.01364v1","created_at":"2026-05-18T00:22:22Z"},{"alias_kind":"doi","alias_value":"10.48550/arxiv.1802.01364","created_at":"2026-05-18T00:22:22Z"},{"alias_kind":"pith_short_12","alias_value":"MYITBZXK46YH","created_at":"2026-05-18T12:32:40Z"},{"alias_kind":"pith_short_16","alias_value":"MYITBZXK46YHSDUL","created_at":"2026-05-18T12:32:40Z"},{"alias_kind":"pith_short_8","alias_value":"MYITBZXK","created_at":"2026-05-18T12:32:40Z"}],"graph_snapshots":[{"event_id":"sha256:040b4ee7ce2a6559dd52f6689cb4710b5e6d0ec8835a9ea0afdf1d6714949f63","target":"graph","created_at":"2026-05-18T00:22:22Z","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":"We demonstrate numerical techniques for automatic identification of individual spiral arms in hydrodynamic simulations of astrophysical discs. Building on our earlier work, which used tensor classification to identify regions that were \"spiral-like\", we can now obtain fits to spirals for individual arm elements. We show this process can even detect spirals in relatively flocculent spiral patterns, but the resulting fits to logarithmic \"grand-design\" spirals are less robust. Our methods not only permit the estimation of pitch angles, but also direct measurements of the spiral arm width and patt","authors_text":"D.H. Forgan, F.G. Ram\\'on-Fox, I.A. Bonnell","cross_cats":["astro-ph.EP"],"headline":"","license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","primary_cat":"astro-ph.GA","submitted_at":"2018-02-05T12:22:24Z","title":"Classifying and modelling spiral structures in hydrodynamic simulations of astrophysical discs"},"references":{"count":0,"internal_anchors":0,"resolved_work":0,"sample":[],"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"source":{"id":"1802.01364","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:b3d7c2d7dbd4759c389c2f40144000bc75d7c0f3c8a589f308e26ed47df3872a","target":"record","created_at":"2026-05-18T00:22:22Z","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":"555bb1537fe836995aa67c6a4746b8d2dddb3936eaa6cc997d0c7952fff77f0e","cross_cats_sorted":["astro-ph.EP"],"license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","primary_cat":"astro-ph.GA","submitted_at":"2018-02-05T12:22:24Z","title_canon_sha256":"39a44ab23cad5c7eed7bec79c4a756de024f901b431a5cbce553ffab26395da6"},"schema_version":"1.0","source":{"id":"1802.01364","kind":"arxiv","version":1}},"canonical_sha256":"661130e6eae7b0790e8b1955c76a950b1985f095e3add8f79d836a709f44d075","receipt":{"algorithm":"ed25519","builder_version":"pith-number-builder-2026-05-17-v1","canonical_sha256":"661130e6eae7b0790e8b1955c76a950b1985f095e3add8f79d836a709f44d075","first_computed_at":"2026-05-18T00:22:22.694712Z","key_id":"pith-v1-2026-05","kind":"pith_receipt","last_reissued_at":"2026-05-18T00:22:22.694712Z","public_key_fingerprint":"8d4b5ee74e4693bcd1df2446408b0d54","receipt_version":"0.3","signature_b64":"3G7WAnJhscrWRS/pz0XQZZJvZKFU6LIxwaFH0CCGElrWZEo1k17bd/q1d73U0Uu9k5L5EYQ4JM14ES0pifvcBw==","signature_status":"signed_v1","signed_at":"2026-05-18T00:22:22.695223Z","signed_message":"canonical_sha256_bytes"},"source_id":"1802.01364","source_kind":"arxiv","source_version":1}}},"equivocations":[],"invalid_events":[],"applied_event_ids":["sha256:b3d7c2d7dbd4759c389c2f40144000bc75d7c0f3c8a589f308e26ed47df3872a","sha256:040b4ee7ce2a6559dd52f6689cb4710b5e6d0ec8835a9ea0afdf1d6714949f63"],"state_sha256":"03656971106e209eed48d5f973a3ab6473b335f4bb1c9d4b40f9399dbe3c92b6"},"bundle_signature":{"signature_status":"signed_v1","algorithm":"ed25519","key_id":"pith-v1-2026-05","public_key_fingerprint":"8d4b5ee74e4693bcd1df2446408b0d54","signature_b64":"ZJIijHlyQV2t61hIt1MkC+Ywr6LC4rDjrP80OPIWKOrDA6AsmEw6TkyEeiHbJ84z02U8cNkPm7OVPLAuy3L5CA==","signed_message":"bundle_sha256_bytes","signed_at":"2026-05-23T09:34:11.497752Z","bundle_sha256":"613035f40dfd20b659924d536db6575e2227d89e1bf7ce3b846bd0673fd6d831"}}