{"bundle_type":"pith_open_graph_bundle","bundle_version":"1.0","pith_number":"pith:2016:G7KMLXE6LBYYK5ETFXFEAOJ65R","short_pith_number":"pith:G7KMLXE6","canonical_record":{"source":{"id":"1607.04325","kind":"arxiv","version":1},"metadata":{"license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","primary_cat":"astro-ph.GA","submitted_at":"2016-07-14T21:21:48Z","cross_cats_sorted":[],"title_canon_sha256":"3f23e333b835a9dc8c743b80ed78c5f1f0c2b5057a6c4fd72fcf2479a0d3666c","abstract_canon_sha256":"c223fccbbe27bd5e6514051fe382815d586c4a8c743df68dc52fddfba760f174"},"schema_version":"1.0"},"canonical_sha256":"37d4c5dc9e58718574932dca40393eec447fc417eac3cc7d4e351ef5bff304c2","source":{"kind":"arxiv","id":"1607.04325","version":1},"source_aliases":[{"alias_kind":"arxiv","alias_value":"1607.04325","created_at":"2026-05-18T01:03:18Z"},{"alias_kind":"arxiv_version","alias_value":"1607.04325v1","created_at":"2026-05-18T01:03:18Z"},{"alias_kind":"doi","alias_value":"10.48550/arxiv.1607.04325","created_at":"2026-05-18T01:03:18Z"},{"alias_kind":"pith_short_12","alias_value":"G7KMLXE6LBYY","created_at":"2026-05-18T12:30:15Z"},{"alias_kind":"pith_short_16","alias_value":"G7KMLXE6LBYYK5ET","created_at":"2026-05-18T12:30:15Z"},{"alias_kind":"pith_short_8","alias_value":"G7KMLXE6","created_at":"2026-05-18T12:30:15Z"}],"events":[{"event_type":"record_created","subject_pith_number":"pith:2016:G7KMLXE6LBYYK5ETFXFEAOJ65R","target":"record","payload":{"canonical_record":{"source":{"id":"1607.04325","kind":"arxiv","version":1},"metadata":{"license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","primary_cat":"astro-ph.GA","submitted_at":"2016-07-14T21:21:48Z","cross_cats_sorted":[],"title_canon_sha256":"3f23e333b835a9dc8c743b80ed78c5f1f0c2b5057a6c4fd72fcf2479a0d3666c","abstract_canon_sha256":"c223fccbbe27bd5e6514051fe382815d586c4a8c743df68dc52fddfba760f174"},"schema_version":"1.0"},"canonical_sha256":"37d4c5dc9e58718574932dca40393eec447fc417eac3cc7d4e351ef5bff304c2","receipt":{"kind":"pith_receipt","key_id":"pith-v1-2026-05","algorithm":"ed25519","signed_at":"2026-05-18T01:03:18.066155Z","signature_b64":"lpNlRVzYn7SY5M7onCpx2tO7vUUzx7rTybQbW9C3FfjvNatJPwKwxXFDFLK1aEV5jOzWXzUrFFm/EN4tOCYDCA==","signed_message":"canonical_sha256_bytes","builder_version":"pith-number-builder-2026-05-17-v1","receipt_version":"0.3","canonical_sha256":"37d4c5dc9e58718574932dca40393eec447fc417eac3cc7d4e351ef5bff304c2","last_reissued_at":"2026-05-18T01:03:18.065540Z","signature_status":"signed_v1","first_computed_at":"2026-05-18T01:03:18.065540Z","public_key_fingerprint":"8d4b5ee74e4693bcd1df2446408b0d54"},"source_kind":"arxiv","source_id":"1607.04325","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":"2026-05-18T01:03:18Z","supersedes":[],"prev_event":null,"signature":{"signature_status":"signed_v1","algorithm":"ed25519","key_id":"pith-v1-2026-05","public_key_fingerprint":"8d4b5ee74e4693bcd1df2446408b0d54","signature_b64":"msXmohBvMnoXSW/d3hEUQ3yZVUjUaLCzZhsMJ88T4gcs528aZ9i+m/YLjDfqOn63BDvM+YlHTXwrPKgNskWkCg==","signed_message":"open_graph_event_sha256_bytes","signed_at":"2026-05-27T10:16:46.574244Z"},"content_sha256":"2e64f64299aeb45f213fddd1c11832a9651e341141224afc70f224d033051e74","schema_version":"1.0","event_id":"sha256:2e64f64299aeb45f213fddd1c11832a9651e341141224afc70f224d033051e74"},{"event_type":"graph_snapshot","subject_pith_number":"pith:2016:G7KMLXE6LBYYK5ETFXFEAOJ65R","target":"graph","payload":{"graph_snapshot":{"paper":{"title":"A spectroscopic study of blue supergiant stars in the Sculptor galaxy NGC 55: chemical evolution and distance","license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","headline":"","cross_cats":[],"primary_cat":"astro-ph.GA","authors_text":"Fabio Bresolin, Grzegorz Pietrzynski, I-Ting Ho, Miguel Urbaneja, Norberto Castro, Norbert Przybilla, Rolf Kudritzki, Wolfgang Gieren","submitted_at":"2016-07-14T21:21:48Z","abstract_excerpt":"Low resolution (4.5 to 5 Angstroem) spectra of 58 blue supergiant stars distributed over the disk of the Magellanic spiral galaxy NGC 55 in the Sculptor group are analyzed by means of non-LTE techniques to determine stellar temperatures, gravities and metallicities (from iron peak and alpha-elements). A metallicity gradient of -0.22 +/- 0.06$ dex/R_25 is detected. The central metallicity on a logarithmic scale relative to the Sun is [Z] = -0.37 +\\- 0.03. A chemical evolution model using the observed distribution of stellar and interstellar medium gas mass column densities reproduces the observ"},"claims":{"count":0,"items":[],"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"source":{"id":"1607.04325","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":"2026-05-18T01:03:18Z","supersedes":[],"prev_event":null,"signature":{"signature_status":"signed_v1","algorithm":"ed25519","key_id":"pith-v1-2026-05","public_key_fingerprint":"8d4b5ee74e4693bcd1df2446408b0d54","signature_b64":"Am1DiGKZGkm3BIUdXrUJIlZtwnvMYpMQ5sKvGZuCR0cFX1jTjXrzUsHy+db1IXv9rGfZhdKzMIrKtfkRRmnzDg==","signed_message":"open_graph_event_sha256_bytes","signed_at":"2026-05-27T10:16:46.574922Z"},"content_sha256":"0d7c8cfbf7b44b7078dd5c6d29de4ed69df9d16c0e451d6595d201eba446c36a","schema_version":"1.0","event_id":"sha256:0d7c8cfbf7b44b7078dd5c6d29de4ed69df9d16c0e451d6595d201eba446c36a"}],"timestamp_proofs":[],"mirror_hints":[{"mirror_type":"https","name":"Pith Resolver","base_url":"https://pith.science","bundle_url":"https://pith.science/pith/G7KMLXE6LBYYK5ETFXFEAOJ65R/bundle.json","state_url":"https://pith.science/pith/G7KMLXE6LBYYK5ETFXFEAOJ65R/state.json","well_known_bundle_url":"https://pith.science/.well-known/pith/G7KMLXE6LBYYK5ETFXFEAOJ65R/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":"2026-05-27T10:16:46Z","links":{"resolver":"https://pith.science/pith/G7KMLXE6LBYYK5ETFXFEAOJ65R","bundle":"https://pith.science/pith/G7KMLXE6LBYYK5ETFXFEAOJ65R/bundle.json","state":"https://pith.science/pith/G7KMLXE6LBYYK5ETFXFEAOJ65R/state.json","well_known_bundle":"https://pith.science/.well-known/pith/G7KMLXE6LBYYK5ETFXFEAOJ65R/bundle.json"},"state":{"state_type":"pith_open_graph_state","state_version":"1.0","pith_number":"pith:2016:G7KMLXE6LBYYK5ETFXFEAOJ65R","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":"c223fccbbe27bd5e6514051fe382815d586c4a8c743df68dc52fddfba760f174","cross_cats_sorted":[],"license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","primary_cat":"astro-ph.GA","submitted_at":"2016-07-14T21:21:48Z","title_canon_sha256":"3f23e333b835a9dc8c743b80ed78c5f1f0c2b5057a6c4fd72fcf2479a0d3666c"},"schema_version":"1.0","source":{"id":"1607.04325","kind":"arxiv","version":1}},"source_aliases":[{"alias_kind":"arxiv","alias_value":"1607.04325","created_at":"2026-05-18T01:03:18Z"},{"alias_kind":"arxiv_version","alias_value":"1607.04325v1","created_at":"2026-05-18T01:03:18Z"},{"alias_kind":"doi","alias_value":"10.48550/arxiv.1607.04325","created_at":"2026-05-18T01:03:18Z"},{"alias_kind":"pith_short_12","alias_value":"G7KMLXE6LBYY","created_at":"2026-05-18T12:30:15Z"},{"alias_kind":"pith_short_16","alias_value":"G7KMLXE6LBYYK5ET","created_at":"2026-05-18T12:30:15Z"},{"alias_kind":"pith_short_8","alias_value":"G7KMLXE6","created_at":"2026-05-18T12:30:15Z"}],"graph_snapshots":[{"event_id":"sha256:0d7c8cfbf7b44b7078dd5c6d29de4ed69df9d16c0e451d6595d201eba446c36a","target":"graph","created_at":"2026-05-18T01:03:18Z","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":"Low resolution (4.5 to 5 Angstroem) spectra of 58 blue supergiant stars distributed over the disk of the Magellanic spiral galaxy NGC 55 in the Sculptor group are analyzed by means of non-LTE techniques to determine stellar temperatures, gravities and metallicities (from iron peak and alpha-elements). A metallicity gradient of -0.22 +/- 0.06$ dex/R_25 is detected. The central metallicity on a logarithmic scale relative to the Sun is [Z] = -0.37 +\\- 0.03. A chemical evolution model using the observed distribution of stellar and interstellar medium gas mass column densities reproduces the observ","authors_text":"Fabio Bresolin, Grzegorz Pietrzynski, I-Ting Ho, Miguel Urbaneja, Norberto Castro, Norbert Przybilla, Rolf Kudritzki, Wolfgang Gieren","cross_cats":[],"headline":"","license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","primary_cat":"astro-ph.GA","submitted_at":"2016-07-14T21:21:48Z","title":"A spectroscopic study of blue supergiant stars in the Sculptor galaxy NGC 55: chemical evolution and distance"},"references":{"count":0,"internal_anchors":0,"resolved_work":0,"sample":[],"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"source":{"id":"1607.04325","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":"sha256:2e64f64299aeb45f213fddd1c11832a9651e341141224afc70f224d033051e74","target":"record","created_at":"2026-05-18T01:03:18Z","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":"c223fccbbe27bd5e6514051fe382815d586c4a8c743df68dc52fddfba760f174","cross_cats_sorted":[],"license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","primary_cat":"astro-ph.GA","submitted_at":"2016-07-14T21:21:48Z","title_canon_sha256":"3f23e333b835a9dc8c743b80ed78c5f1f0c2b5057a6c4fd72fcf2479a0d3666c"},"schema_version":"1.0","source":{"id":"1607.04325","kind":"arxiv","version":1}},"canonical_sha256":"37d4c5dc9e58718574932dca40393eec447fc417eac3cc7d4e351ef5bff304c2","receipt":{"algorithm":"ed25519","builder_version":"pith-number-builder-2026-05-17-v1","canonical_sha256":"37d4c5dc9e58718574932dca40393eec447fc417eac3cc7d4e351ef5bff304c2","first_computed_at":"2026-05-18T01:03:18.065540Z","key_id":"pith-v1-2026-05","kind":"pith_receipt","last_reissued_at":"2026-05-18T01:03:18.065540Z","public_key_fingerprint":"8d4b5ee74e4693bcd1df2446408b0d54","receipt_version":"0.3","signature_b64":"lpNlRVzYn7SY5M7onCpx2tO7vUUzx7rTybQbW9C3FfjvNatJPwKwxXFDFLK1aEV5jOzWXzUrFFm/EN4tOCYDCA==","signature_status":"signed_v1","signed_at":"2026-05-18T01:03:18.066155Z","signed_message":"canonical_sha256_bytes"},"source_id":"1607.04325","source_kind":"arxiv","source_version":1}}},"equivocations":[],"invalid_events":[],"applied_event_ids":["sha256:2e64f64299aeb45f213fddd1c11832a9651e341141224afc70f224d033051e74","sha256:0d7c8cfbf7b44b7078dd5c6d29de4ed69df9d16c0e451d6595d201eba446c36a"],"state_sha256":"070bf8a3aebc227ce1d9a22387a784ac14cc23164b3cc0e9db7fa1908c6bf1dc"},"bundle_signature":{"signature_status":"signed_v1","algorithm":"ed25519","key_id":"pith-v1-2026-05","public_key_fingerprint":"8d4b5ee74e4693bcd1df2446408b0d54","signature_b64":"HzZLcDgizZDayz8p1BG6ro5gbrPEMkin2cLARmRW2qUXOiAJInY1kXnJAbg+7m1LVh3aENHAWDoff5uEVERJBQ==","signed_message":"bundle_sha256_bytes","signed_at":"2026-05-27T10:16:46.577920Z","bundle_sha256":"70a160bf28f2c185caa6d5934575a175cae15f8b8803cfcc6dbe44b6b34b1084"}}