{"bundle_type":"pith_open_graph_bundle","bundle_version":"1.0","pith_number":"pith:2021:OZ6N4HZSIPLQ2QAQ6NZ5Q5LED6","short_pith_number":"pith:OZ6N4HZS","canonical_record":{"source":{"id":"2109.12943","kind":"arxiv","version":1},"metadata":{"license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","primary_cat":"astro-ph.HE","submitted_at":"2021-09-27T10:47:57Z","cross_cats_sorted":["astro-ph.SR"],"title_canon_sha256":"9802696093d5496ad1dc59ce49522afa3e8090885f55af9f5669477c90c664b6","abstract_canon_sha256":"7b19bf16b86030ed5423b4b2bbaffe8955d4cb3d9c289fbfef60093fc8c5b953"},"schema_version":"1.0"},"canonical_sha256":"767cde1f3243d70d4010f373d875641fbdb7eb025d7c52c2cfd0631326f1f18b","source":{"kind":"arxiv","id":"2109.12943","version":1},"source_aliases":[{"alias_kind":"arxiv","alias_value":"2109.12943","created_at":"2026-07-05T03:17:39Z"},{"alias_kind":"arxiv_version","alias_value":"2109.12943v1","created_at":"2026-07-05T03:17:39Z"},{"alias_kind":"doi","alias_value":"10.48550/arxiv.2109.12943","created_at":"2026-07-05T03:17:39Z"},{"alias_kind":"pith_short_12","alias_value":"OZ6N4HZSIPLQ","created_at":"2026-07-05T03:17:39Z"},{"alias_kind":"pith_short_16","alias_value":"OZ6N4HZSIPLQ2QAQ","created_at":"2026-07-05T03:17:39Z"},{"alias_kind":"pith_short_8","alias_value":"OZ6N4HZS","created_at":"2026-07-05T03:17:39Z"}],"events":[{"event_type":"record_created","subject_pith_number":"pith:2021:OZ6N4HZSIPLQ2QAQ6NZ5Q5LED6","target":"record","payload":{"canonical_record":{"source":{"id":"2109.12943","kind":"arxiv","version":1},"metadata":{"license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","primary_cat":"astro-ph.HE","submitted_at":"2021-09-27T10:47:57Z","cross_cats_sorted":["astro-ph.SR"],"title_canon_sha256":"9802696093d5496ad1dc59ce49522afa3e8090885f55af9f5669477c90c664b6","abstract_canon_sha256":"7b19bf16b86030ed5423b4b2bbaffe8955d4cb3d9c289fbfef60093fc8c5b953"},"schema_version":"1.0"},"canonical_sha256":"767cde1f3243d70d4010f373d875641fbdb7eb025d7c52c2cfd0631326f1f18b","receipt":{"kind":"pith_receipt","key_id":"pith-v1-2026-05","algorithm":"ed25519","signed_at":"2026-07-05T03:17:39.133880Z","signature_b64":"GhIoB8se8THGb1SD0vfXO6D7yZAeDLkaaUwWCmNG0mfvQNGlhY8EATpL3eToWafyx92jvx+xtbpMl5AnBAk1Dw==","signed_message":"canonical_sha256_bytes","builder_version":"pith-number-builder-2026-05-17-v1","receipt_version":"0.3","canonical_sha256":"767cde1f3243d70d4010f373d875641fbdb7eb025d7c52c2cfd0631326f1f18b","last_reissued_at":"2026-07-05T03:17:39.133391Z","signature_status":"signed_v1","first_computed_at":"2026-07-05T03:17:39.133391Z","public_key_fingerprint":"8d4b5ee74e4693bcd1df2446408b0d54"},"source_kind":"arxiv","source_id":"2109.12943","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":"2026-07-05T03:17:39Z","supersedes":[],"prev_event":null,"signature":{"signature_status":"signed_v1","algorithm":"ed25519","key_id":"pith-v1-2026-05","public_key_fingerprint":"8d4b5ee74e4693bcd1df2446408b0d54","signature_b64":"oTosA8zOjXJXp9vrTXvtn3Re+PaLcsElEK4VGvmlp/OeLFBl3ZH9hYRmGp1oZ4FeFzJuFHsVSoMdORcE7OecDw==","signed_message":"open_graph_event_sha256_bytes","signed_at":"2026-07-31T23:43:12.459368Z"},"content_sha256":"4debb6da3be1f6d54c764743173a005799c44d8d6aa21422223b8df11016df15","schema_version":"1.0","event_id":"sha256:4debb6da3be1f6d54c764743173a005799c44d8d6aa21422223b8df11016df15"},{"event_type":"graph_snapshot","subject_pith_number":"pith:2021:OZ6N4HZSIPLQ2QAQ6NZ5Q5LED6","target":"graph","payload":{"graph_snapshot":{"paper":{"title":"How low can you go? SN 2018zd as a low-mass Fe core-collapse supernova","license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","headline":"","cross_cats":["astro-ph.SR"],"primary_cat":"astro-ph.HE","authors_text":"A. Pastorello, A. Reguitti, A. Sagu\\'es-Carracedo, A. Siviero, B. J. Shappee, C. P. Guti\\'errez, D. Eappachen, E. Callis, E. Cappellaro, E. Congiu, E. Kankare, G. Cannizzaro, J. Prieto, J. Ryon, K. G. Stassun, K. Itagaki, L. Salmon, L. Tomasella, M. Berton, M. Fraser, M. Gromadzki, M. Stritzinger, N. Elias-Rosa, P. Chen, P. Jonker, P. Ochner, P. Wiggins, R. Mutel, R. S. Post, S. Benetti, S. Bose, S. Dyrbye, S. Holmbo, S. J. Brennan, S. Mattila, Subo Dong, S. Villanueva Jr., T. Reynolds, T. Roth, T. Wevers, T. W. S. Holoien","submitted_at":"2021-09-27T10:47:57Z","abstract_excerpt":"We present spectroscopy and photometry of SN 2018zd, a Type IIP core-collapse supernova with signatures of interaction with circumstantial material in its earliest spectra. High ionization lines, the earmark of shock breakout, are not seen in the earliest spectral epoch, and are only seen in a single spectrum at 4.9 d after explosion. The strength and brevity of these features imply a confined circumstellar material shell in the immediate vicinity of the progenitor. Once the narrow emission lines disappear, SN 2018zd evolves similarly to a Type IIP SN, although the blue colour and enhanced pla"},"claims":{"count":0,"items":[],"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"source":{"id":"2109.12943","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":""},"integrity":{"clean":true,"summary":{"advisory":0,"critical":0,"by_detector":{},"informational":0},"endpoint":"/pith/2109.12943/integrity.json","findings":[],"available":true,"detectors_run":[],"snapshot_sha256":"c28c3603d3b5d939e8dc4c7e95fa8dfce3d595e45f758748cecf8e644a296938"},"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":"2026-07-05T03:17:39Z","supersedes":[],"prev_event":null,"signature":{"signature_status":"signed_v1","algorithm":"ed25519","key_id":"pith-v1-2026-05","public_key_fingerprint":"8d4b5ee74e4693bcd1df2446408b0d54","signature_b64":"oUO2qXFIYx+D8v/5Q0z2l/zEF7nVTsxNp1QcnP3pJhdfZ3ise2MN/dwlgCD7OF6NLOYqepjNyk7rkHzQpcIOAA==","signed_message":"open_graph_event_sha256_bytes","signed_at":"2026-07-31T23:43:12.459908Z"},"content_sha256":"f7ff4f38239328513c53e9b506076f9638b0b93c1ac1c1fdf1485afa0a4481da","schema_version":"1.0","event_id":"sha256:f7ff4f38239328513c53e9b506076f9638b0b93c1ac1c1fdf1485afa0a4481da"}],"timestamp_proofs":[],"mirror_hints":[{"mirror_type":"https","name":"Pith Resolver","base_url":"https://pith.science","bundle_url":"https://pith.science/pith/OZ6N4HZSIPLQ2QAQ6NZ5Q5LED6/bundle.json","state_url":"https://pith.science/pith/OZ6N4HZSIPLQ2QAQ6NZ5Q5LED6/state.json","well_known_bundle_url":"https://pith.science/.well-known/pith/OZ6N4HZSIPLQ2QAQ6NZ5Q5LED6/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":"2026-07-31T23:43:12Z","links":{"resolver":"https://pith.science/pith/OZ6N4HZSIPLQ2QAQ6NZ5Q5LED6","bundle":"https://pith.science/pith/OZ6N4HZSIPLQ2QAQ6NZ5Q5LED6/bundle.json","state":"https://pith.science/pith/OZ6N4HZSIPLQ2QAQ6NZ5Q5LED6/state.json","well_known_bundle":"https://pith.science/.well-known/pith/OZ6N4HZSIPLQ2QAQ6NZ5Q5LED6/bundle.json"},"state":{"state_type":"pith_open_graph_state","state_version":"1.0","pith_number":"pith:2021:OZ6N4HZSIPLQ2QAQ6NZ5Q5LED6","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":"7b19bf16b86030ed5423b4b2bbaffe8955d4cb3d9c289fbfef60093fc8c5b953","cross_cats_sorted":["astro-ph.SR"],"license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","primary_cat":"astro-ph.HE","submitted_at":"2021-09-27T10:47:57Z","title_canon_sha256":"9802696093d5496ad1dc59ce49522afa3e8090885f55af9f5669477c90c664b6"},"schema_version":"1.0","source":{"id":"2109.12943","kind":"arxiv","version":1}},"source_aliases":[{"alias_kind":"arxiv","alias_value":"2109.12943","created_at":"2026-07-05T03:17:39Z"},{"alias_kind":"arxiv_version","alias_value":"2109.12943v1","created_at":"2026-07-05T03:17:39Z"},{"alias_kind":"doi","alias_value":"10.48550/arxiv.2109.12943","created_at":"2026-07-05T03:17:39Z"},{"alias_kind":"pith_short_12","alias_value":"OZ6N4HZSIPLQ","created_at":"2026-07-05T03:17:39Z"},{"alias_kind":"pith_short_16","alias_value":"OZ6N4HZSIPLQ2QAQ","created_at":"2026-07-05T03:17:39Z"},{"alias_kind":"pith_short_8","alias_value":"OZ6N4HZS","created_at":"2026-07-05T03:17:39Z"}],"graph_snapshots":[{"event_id":"sha256:f7ff4f38239328513c53e9b506076f9638b0b93c1ac1c1fdf1485afa0a4481da","target":"graph","created_at":"2026-07-05T03:17:39Z","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"},"integrity":{"available":true,"clean":true,"detectors_run":[],"endpoint":"/pith/2109.12943/integrity.json","findings":[],"snapshot_sha256":"c28c3603d3b5d939e8dc4c7e95fa8dfce3d595e45f758748cecf8e644a296938","summary":{"advisory":0,"by_detector":{},"critical":0,"informational":0}},"paper":{"abstract_excerpt":"We present spectroscopy and photometry of SN 2018zd, a Type IIP core-collapse supernova with signatures of interaction with circumstantial material in its earliest spectra. High ionization lines, the earmark of shock breakout, are not seen in the earliest spectral epoch, and are only seen in a single spectrum at 4.9 d after explosion. The strength and brevity of these features imply a confined circumstellar material shell in the immediate vicinity of the progenitor. Once the narrow emission lines disappear, SN 2018zd evolves similarly to a Type IIP SN, although the blue colour and enhanced pla","authors_text":"A. Pastorello, A. Reguitti, A. Sagu\\'es-Carracedo, A. Siviero, B. J. Shappee, C. P. Guti\\'errez, D. Eappachen, E. Callis, E. Cappellaro, E. Congiu, E. Kankare, G. Cannizzaro, J. Prieto, J. Ryon, K. G. Stassun, K. Itagaki, L. Salmon, L. Tomasella, M. Berton, M. Fraser, M. Gromadzki, M. Stritzinger, N. Elias-Rosa, P. Chen, P. Jonker, P. Ochner, P. Wiggins, R. Mutel, R. S. Post, S. Benetti, S. Bose, S. Dyrbye, S. Holmbo, S. J. Brennan, S. Mattila, Subo Dong, S. Villanueva Jr., T. Reynolds, T. Roth, T. Wevers, T. W. S. Holoien","cross_cats":["astro-ph.SR"],"headline":"","license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","primary_cat":"astro-ph.HE","submitted_at":"2021-09-27T10:47:57Z","title":"How low can you go? SN 2018zd as a low-mass Fe core-collapse supernova"},"references":{"count":0,"internal_anchors":0,"resolved_work":0,"sample":[],"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"source":{"id":"2109.12943","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":"sha256:4debb6da3be1f6d54c764743173a005799c44d8d6aa21422223b8df11016df15","target":"record","created_at":"2026-07-05T03:17:39Z","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":"7b19bf16b86030ed5423b4b2bbaffe8955d4cb3d9c289fbfef60093fc8c5b953","cross_cats_sorted":["astro-ph.SR"],"license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","primary_cat":"astro-ph.HE","submitted_at":"2021-09-27T10:47:57Z","title_canon_sha256":"9802696093d5496ad1dc59ce49522afa3e8090885f55af9f5669477c90c664b6"},"schema_version":"1.0","source":{"id":"2109.12943","kind":"arxiv","version":1}},"canonical_sha256":"767cde1f3243d70d4010f373d875641fbdb7eb025d7c52c2cfd0631326f1f18b","receipt":{"algorithm":"ed25519","builder_version":"pith-number-builder-2026-05-17-v1","canonical_sha256":"767cde1f3243d70d4010f373d875641fbdb7eb025d7c52c2cfd0631326f1f18b","first_computed_at":"2026-07-05T03:17:39.133391Z","key_id":"pith-v1-2026-05","kind":"pith_receipt","last_reissued_at":"2026-07-05T03:17:39.133391Z","public_key_fingerprint":"8d4b5ee74e4693bcd1df2446408b0d54","receipt_version":"0.3","signature_b64":"GhIoB8se8THGb1SD0vfXO6D7yZAeDLkaaUwWCmNG0mfvQNGlhY8EATpL3eToWafyx92jvx+xtbpMl5AnBAk1Dw==","signature_status":"signed_v1","signed_at":"2026-07-05T03:17:39.133880Z","signed_message":"canonical_sha256_bytes"},"source_id":"2109.12943","source_kind":"arxiv","source_version":1}}},"equivocations":[],"invalid_events":[],"applied_event_ids":["sha256:4debb6da3be1f6d54c764743173a005799c44d8d6aa21422223b8df11016df15","sha256:f7ff4f38239328513c53e9b506076f9638b0b93c1ac1c1fdf1485afa0a4481da"],"state_sha256":"4d815c00e9e8fee8763f3251877f15d0d4a0b280713438f94f5e5fbb289fe7f5"},"bundle_signature":{"signature_status":"signed_v1","algorithm":"ed25519","key_id":"pith-v1-2026-05","public_key_fingerprint":"8d4b5ee74e4693bcd1df2446408b0d54","signature_b64":"ca/sYM/bsmTKsL99etWLcNvwVj+8qKO4jyPaWGzmT+GeZUHfnvfY7FrZUI6Khxq5HdMOxOfVGUfpTN6V1ujHDg==","signed_message":"bundle_sha256_bytes","signed_at":"2026-07-31T23:43:12.463818Z","bundle_sha256":"21a8274d52e525656fc7a784116712839cce5dec671f4e8da6f09286e18a6543"}}