{"bundle_type":"pith_open_graph_bundle","bundle_version":"1.0","pith_number":"pith:2019:EYRPKBJSCY2L3HFG2BD4ZOBYON","short_pith_number":"pith:EYRPKBJS","canonical_record":{"source":{"id":"1904.00803","kind":"arxiv","version":1},"metadata":{"license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","primary_cat":"astro-ph.GA","submitted_at":"2019-03-28T19:50:14Z","cross_cats_sorted":[],"title_canon_sha256":"429d87d5376e55160bbf491c8fc7ad567d004284a06d23bd55a3a09bccaed677","abstract_canon_sha256":"6e52118f237fdb71380957625e1628eccf3adbfd3c4280387463e11944daa04e"},"schema_version":"1.0"},"canonical_sha256":"2622f505321634bd9ca6d047ccb83873537d021d6168d206f7f44c2a0cbe4d46","source":{"kind":"arxiv","id":"1904.00803","version":1},"source_aliases":[{"alias_kind":"arxiv","alias_value":"1904.00803","created_at":"2026-05-17T23:49:45Z"},{"alias_kind":"arxiv_version","alias_value":"1904.00803v1","created_at":"2026-05-17T23:49:45Z"},{"alias_kind":"doi","alias_value":"10.48550/arxiv.1904.00803","created_at":"2026-05-17T23:49:45Z"},{"alias_kind":"pith_short_12","alias_value":"EYRPKBJSCY2L","created_at":"2026-05-18T12:33:15Z"},{"alias_kind":"pith_short_16","alias_value":"EYRPKBJSCY2L3HFG","created_at":"2026-05-18T12:33:15Z"},{"alias_kind":"pith_short_8","alias_value":"EYRPKBJS","created_at":"2026-05-18T12:33:15Z"}],"events":[{"event_type":"record_created","subject_pith_number":"pith:2019:EYRPKBJSCY2L3HFG2BD4ZOBYON","target":"record","payload":{"canonical_record":{"source":{"id":"1904.00803","kind":"arxiv","version":1},"metadata":{"license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","primary_cat":"astro-ph.GA","submitted_at":"2019-03-28T19:50:14Z","cross_cats_sorted":[],"title_canon_sha256":"429d87d5376e55160bbf491c8fc7ad567d004284a06d23bd55a3a09bccaed677","abstract_canon_sha256":"6e52118f237fdb71380957625e1628eccf3adbfd3c4280387463e11944daa04e"},"schema_version":"1.0"},"canonical_sha256":"2622f505321634bd9ca6d047ccb83873537d021d6168d206f7f44c2a0cbe4d46","receipt":{"kind":"pith_receipt","key_id":"pith-v1-2026-05","algorithm":"ed25519","signed_at":"2026-05-17T23:49:45.442187Z","signature_b64":"79WK3oXRYNOBDGJCTozxxsZ8ggspngdEkeHiC1j1ctBVvGwveU/HPpa4BG6ik/IsDzoOENaVEy7T2o82PYLlCQ==","signed_message":"canonical_sha256_bytes","builder_version":"pith-number-builder-2026-05-17-v1","receipt_version":"0.3","canonical_sha256":"2622f505321634bd9ca6d047ccb83873537d021d6168d206f7f44c2a0cbe4d46","last_reissued_at":"2026-05-17T23:49:45.441573Z","signature_status":"signed_v1","first_computed_at":"2026-05-17T23:49:45.441573Z","public_key_fingerprint":"8d4b5ee74e4693bcd1df2446408b0d54"},"source_kind":"arxiv","source_id":"1904.00803","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":"2026-05-17T23:49:45Z","supersedes":[],"prev_event":null,"signature":{"signature_status":"signed_v1","algorithm":"ed25519","key_id":"pith-v1-2026-05","public_key_fingerprint":"8d4b5ee74e4693bcd1df2446408b0d54","signature_b64":"BLohryB1Qe/RRH8D8QHCWlGxbl9e3DDsY4htkWgftXVAqb2VsqzrqXJD6938XU4KbB99/IjSFPErnAf4GpvKDw==","signed_message":"open_graph_event_sha256_bytes","signed_at":"2026-05-24T22:34:35.440123Z"},"content_sha256":"b63dd0847d680dc822084addb32d0ab2a793e24872709c19283cbd76e41ea0e9","schema_version":"1.0","event_id":"sha256:b63dd0847d680dc822084addb32d0ab2a793e24872709c19283cbd76e41ea0e9"},{"event_type":"graph_snapshot","subject_pith_number":"pith:2019:EYRPKBJSCY2L3HFG2BD4ZOBYON","target":"graph","payload":{"graph_snapshot":{"paper":{"title":"A Formaldehyde Deep Field","license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","headline":"","cross_cats":[],"primary_cat":"astro-ph.GA","authors_text":"Jeremy Darling","submitted_at":"2019-03-28T19:50:14Z","abstract_excerpt":"Formaldehyde (H2CO) is often observed at centimeter wavelengths as an absorption line against the cosmic microwave background (CMB). This is possible when energy level populations are cooled to the point where line excitation temperatures fall below the local CMB temperature. Collisions with molecular hydrogen \"pump\" this anti-maser excitation, and the cm line ratios of H2CO provide a measurement of the local H2 density. H2CO absorption of CMB light provides all of the benefits of absorption lines (no distance dimming) but none of the drawbacks: the CMB provides uniform illumination of all mol"},"claims":{"count":0,"items":[],"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"source":{"id":"1904.00803","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":"2026-05-17T23:49:45Z","supersedes":[],"prev_event":null,"signature":{"signature_status":"signed_v1","algorithm":"ed25519","key_id":"pith-v1-2026-05","public_key_fingerprint":"8d4b5ee74e4693bcd1df2446408b0d54","signature_b64":"8LSJZx8vQnI4bcZVNnurrTiYycllVBfn9B7Y//ooCkFEeXckJrAFL75Bl68AXSByRbFjZP6FGf0gIXNXdbAbBQ==","signed_message":"open_graph_event_sha256_bytes","signed_at":"2026-05-24T22:34:35.440605Z"},"content_sha256":"38e88c11c6454cd7d631cbe3c6fc2c9693e91f039f350c0aebd8d85bf53c810c","schema_version":"1.0","event_id":"sha256:38e88c11c6454cd7d631cbe3c6fc2c9693e91f039f350c0aebd8d85bf53c810c"}],"timestamp_proofs":[],"mirror_hints":[{"mirror_type":"https","name":"Pith Resolver","base_url":"https://pith.science","bundle_url":"https://pith.science/pith/EYRPKBJSCY2L3HFG2BD4ZOBYON/bundle.json","state_url":"https://pith.science/pith/EYRPKBJSCY2L3HFG2BD4ZOBYON/state.json","well_known_bundle_url":"https://pith.science/.well-known/pith/EYRPKBJSCY2L3HFG2BD4ZOBYON/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":"2026-05-24T22:34:35Z","links":{"resolver":"https://pith.science/pith/EYRPKBJSCY2L3HFG2BD4ZOBYON","bundle":"https://pith.science/pith/EYRPKBJSCY2L3HFG2BD4ZOBYON/bundle.json","state":"https://pith.science/pith/EYRPKBJSCY2L3HFG2BD4ZOBYON/state.json","well_known_bundle":"https://pith.science/.well-known/pith/EYRPKBJSCY2L3HFG2BD4ZOBYON/bundle.json"},"state":{"state_type":"pith_open_graph_state","state_version":"1.0","pith_number":"pith:2019:EYRPKBJSCY2L3HFG2BD4ZOBYON","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":"6e52118f237fdb71380957625e1628eccf3adbfd3c4280387463e11944daa04e","cross_cats_sorted":[],"license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","primary_cat":"astro-ph.GA","submitted_at":"2019-03-28T19:50:14Z","title_canon_sha256":"429d87d5376e55160bbf491c8fc7ad567d004284a06d23bd55a3a09bccaed677"},"schema_version":"1.0","source":{"id":"1904.00803","kind":"arxiv","version":1}},"source_aliases":[{"alias_kind":"arxiv","alias_value":"1904.00803","created_at":"2026-05-17T23:49:45Z"},{"alias_kind":"arxiv_version","alias_value":"1904.00803v1","created_at":"2026-05-17T23:49:45Z"},{"alias_kind":"doi","alias_value":"10.48550/arxiv.1904.00803","created_at":"2026-05-17T23:49:45Z"},{"alias_kind":"pith_short_12","alias_value":"EYRPKBJSCY2L","created_at":"2026-05-18T12:33:15Z"},{"alias_kind":"pith_short_16","alias_value":"EYRPKBJSCY2L3HFG","created_at":"2026-05-18T12:33:15Z"},{"alias_kind":"pith_short_8","alias_value":"EYRPKBJS","created_at":"2026-05-18T12:33:15Z"}],"graph_snapshots":[{"event_id":"sha256:38e88c11c6454cd7d631cbe3c6fc2c9693e91f039f350c0aebd8d85bf53c810c","target":"graph","created_at":"2026-05-17T23:49:45Z","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":"Formaldehyde (H2CO) is often observed at centimeter wavelengths as an absorption line against the cosmic microwave background (CMB). This is possible when energy level populations are cooled to the point where line excitation temperatures fall below the local CMB temperature. Collisions with molecular hydrogen \"pump\" this anti-maser excitation, and the cm line ratios of H2CO provide a measurement of the local H2 density. H2CO absorption of CMB light provides all of the benefits of absorption lines (no distance dimming) but none of the drawbacks: the CMB provides uniform illumination of all mol","authors_text":"Jeremy Darling","cross_cats":[],"headline":"","license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","primary_cat":"astro-ph.GA","submitted_at":"2019-03-28T19:50:14Z","title":"A Formaldehyde Deep Field"},"references":{"count":0,"internal_anchors":0,"resolved_work":0,"sample":[],"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"source":{"id":"1904.00803","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:b63dd0847d680dc822084addb32d0ab2a793e24872709c19283cbd76e41ea0e9","target":"record","created_at":"2026-05-17T23:49:45Z","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":"6e52118f237fdb71380957625e1628eccf3adbfd3c4280387463e11944daa04e","cross_cats_sorted":[],"license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","primary_cat":"astro-ph.GA","submitted_at":"2019-03-28T19:50:14Z","title_canon_sha256":"429d87d5376e55160bbf491c8fc7ad567d004284a06d23bd55a3a09bccaed677"},"schema_version":"1.0","source":{"id":"1904.00803","kind":"arxiv","version":1}},"canonical_sha256":"2622f505321634bd9ca6d047ccb83873537d021d6168d206f7f44c2a0cbe4d46","receipt":{"algorithm":"ed25519","builder_version":"pith-number-builder-2026-05-17-v1","canonical_sha256":"2622f505321634bd9ca6d047ccb83873537d021d6168d206f7f44c2a0cbe4d46","first_computed_at":"2026-05-17T23:49:45.441573Z","key_id":"pith-v1-2026-05","kind":"pith_receipt","last_reissued_at":"2026-05-17T23:49:45.441573Z","public_key_fingerprint":"8d4b5ee74e4693bcd1df2446408b0d54","receipt_version":"0.3","signature_b64":"79WK3oXRYNOBDGJCTozxxsZ8ggspngdEkeHiC1j1ctBVvGwveU/HPpa4BG6ik/IsDzoOENaVEy7T2o82PYLlCQ==","signature_status":"signed_v1","signed_at":"2026-05-17T23:49:45.442187Z","signed_message":"canonical_sha256_bytes"},"source_id":"1904.00803","source_kind":"arxiv","source_version":1}}},"equivocations":[],"invalid_events":[],"applied_event_ids":["sha256:b63dd0847d680dc822084addb32d0ab2a793e24872709c19283cbd76e41ea0e9","sha256:38e88c11c6454cd7d631cbe3c6fc2c9693e91f039f350c0aebd8d85bf53c810c"],"state_sha256":"ac971a6de395be4cb73cb8c514700dd1a87d9fe49a5bbbd0ff81c10d67f05259"},"bundle_signature":{"signature_status":"signed_v1","algorithm":"ed25519","key_id":"pith-v1-2026-05","public_key_fingerprint":"8d4b5ee74e4693bcd1df2446408b0d54","signature_b64":"9+i8U4hhqgD0JMJbW/ThuNBvey5m90SFZcW9VTzIpeMtwL3BVDGBeeESEE/19wHYyViiRUZx6mCuHW/GWls5CA==","signed_message":"bundle_sha256_bytes","signed_at":"2026-05-24T22:34:35.443676Z","bundle_sha256":"e5d08bc3bb8afef982a3ebc2f74af9f6bf6572228881870fecab344df2bd6bf7"}}