{"bundle_type":"pith_open_graph_bundle","bundle_version":"1.0","pith_number":"pith:2018:VDZNGVMJPIREPT7V6HRYX5T3LY","short_pith_number":"pith:VDZNGVMJ","canonical_record":{"source":{"id":"1811.03856","kind":"arxiv","version":1},"metadata":{"license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","primary_cat":"astro-ph.GA","submitted_at":"2018-11-09T10:47:25Z","cross_cats_sorted":[],"title_canon_sha256":"0f525b4169c2cc744c8bf265c49190db96e99db94aa185d3aec395a18223a7f0","abstract_canon_sha256":"4a532c4157b427413f61b6ae5b40d72ad55afe4618fdbd9b9a6bbbb4cd5c57d2"},"schema_version":"1.0"},"canonical_sha256":"a8f2d355897a2247cff5f1e38bf67b5e2024eaf7a927668b614a0aa546dff3d0","source":{"kind":"arxiv","id":"1811.03856","version":1},"source_aliases":[{"alias_kind":"arxiv","alias_value":"1811.03856","created_at":"2026-05-17T23:55:43Z"},{"alias_kind":"arxiv_version","alias_value":"1811.03856v1","created_at":"2026-05-17T23:55:43Z"},{"alias_kind":"doi","alias_value":"10.48550/arxiv.1811.03856","created_at":"2026-05-17T23:55:43Z"},{"alias_kind":"pith_short_12","alias_value":"VDZNGVMJPIRE","created_at":"2026-05-18T12:32:59Z"},{"alias_kind":"pith_short_16","alias_value":"VDZNGVMJPIREPT7V","created_at":"2026-05-18T12:32:59Z"},{"alias_kind":"pith_short_8","alias_value":"VDZNGVMJ","created_at":"2026-05-18T12:32:59Z"}],"events":[{"event_type":"record_created","subject_pith_number":"pith:2018:VDZNGVMJPIREPT7V6HRYX5T3LY","target":"record","payload":{"canonical_record":{"source":{"id":"1811.03856","kind":"arxiv","version":1},"metadata":{"license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","primary_cat":"astro-ph.GA","submitted_at":"2018-11-09T10:47:25Z","cross_cats_sorted":[],"title_canon_sha256":"0f525b4169c2cc744c8bf265c49190db96e99db94aa185d3aec395a18223a7f0","abstract_canon_sha256":"4a532c4157b427413f61b6ae5b40d72ad55afe4618fdbd9b9a6bbbb4cd5c57d2"},"schema_version":"1.0"},"canonical_sha256":"a8f2d355897a2247cff5f1e38bf67b5e2024eaf7a927668b614a0aa546dff3d0","receipt":{"kind":"pith_receipt","key_id":"pith-v1-2026-05","algorithm":"ed25519","signed_at":"2026-05-17T23:55:43.778766Z","signature_b64":"3h62SIiffg1H9Jp1Z2ZDtuEkMRZu9fpk1A/i/SefD4BhumRlN78yOYPLBPTYTDftcQuEKUaPGXMMM7fUrlkPAw==","signed_message":"canonical_sha256_bytes","builder_version":"pith-number-builder-2026-05-17-v1","receipt_version":"0.3","canonical_sha256":"a8f2d355897a2247cff5f1e38bf67b5e2024eaf7a927668b614a0aa546dff3d0","last_reissued_at":"2026-05-17T23:55:43.778204Z","signature_status":"signed_v1","first_computed_at":"2026-05-17T23:55:43.778204Z","public_key_fingerprint":"8d4b5ee74e4693bcd1df2446408b0d54"},"source_kind":"arxiv","source_id":"1811.03856","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":"2026-05-17T23:55:43Z","supersedes":[],"prev_event":null,"signature":{"signature_status":"signed_v1","algorithm":"ed25519","key_id":"pith-v1-2026-05","public_key_fingerprint":"8d4b5ee74e4693bcd1df2446408b0d54","signature_b64":"h5BCNPG5Sa7ADwJTybEl4KXhazllLAE90XPUhOffPkEe+XSFWp0kh/rBogS/JCvGZ+DFkmriUuf/LDpRNr8bBA==","signed_message":"open_graph_event_sha256_bytes","signed_at":"2026-05-31T12:56:51.696569Z"},"content_sha256":"8a5dab4272764bfd3fae960ed3de1cbaab62e56af6b38151a0925ef31b2e64ca","schema_version":"1.0","event_id":"sha256:8a5dab4272764bfd3fae960ed3de1cbaab62e56af6b38151a0925ef31b2e64ca"},{"event_type":"graph_snapshot","subject_pith_number":"pith:2018:VDZNGVMJPIREPT7V6HRYX5T3LY","target":"graph","payload":{"graph_snapshot":{"paper":{"title":"Initial Mass Function Variations Cannot Explain the Ionizing Spectrum of Low Metallicity Starbursts","license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","headline":"","cross_cats":[],"primary_cat":"astro-ph.GA","authors_text":"E. R. Stanway (Warwick), J. J. Eldridge (Auckland)","submitted_at":"2018-11-09T10:47:25Z","abstract_excerpt":"Observations of both galaxies in the distant Universe and local starbursts are showing increasing evidence for very hard ionizing spectra that stellar population synthesis models struggle to reproduce. Here we explore the effects of the assumed stellar initial mass function (IMF) on the ionizing photon output of young populations at wavelengths below key ionization energy thresholds. We use a custom set of binary population and spectral synthesis (BPASS) models to explore the effects of IMF assumptions as a function of metallicity, IMF slope, upper mass limit, IMF power law break mass and samp"},"claims":{"count":0,"items":[],"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"source":{"id":"1811.03856","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":"2026-05-17T23:55:43Z","supersedes":[],"prev_event":null,"signature":{"signature_status":"signed_v1","algorithm":"ed25519","key_id":"pith-v1-2026-05","public_key_fingerprint":"8d4b5ee74e4693bcd1df2446408b0d54","signature_b64":"e4FGEIjkwELTrPUpy/i2e7m/RxqKonw0MccXkz0LQsYZEggIBWna1XXXbfC4JFzHt3uUnkSQuucaX9o1hhbEAA==","signed_message":"open_graph_event_sha256_bytes","signed_at":"2026-05-31T12:56:51.697203Z"},"content_sha256":"c8fa8ce353ffb3eb8633998e0b25769ef291237b74609fab35e2c8ec7a2c1838","schema_version":"1.0","event_id":"sha256:c8fa8ce353ffb3eb8633998e0b25769ef291237b74609fab35e2c8ec7a2c1838"}],"timestamp_proofs":[],"mirror_hints":[{"mirror_type":"https","name":"Pith Resolver","base_url":"https://pith.science","bundle_url":"https://pith.science/pith/VDZNGVMJPIREPT7V6HRYX5T3LY/bundle.json","state_url":"https://pith.science/pith/VDZNGVMJPIREPT7V6HRYX5T3LY/state.json","well_known_bundle_url":"https://pith.science/.well-known/pith/VDZNGVMJPIREPT7V6HRYX5T3LY/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":"2026-05-31T12:56:51Z","links":{"resolver":"https://pith.science/pith/VDZNGVMJPIREPT7V6HRYX5T3LY","bundle":"https://pith.science/pith/VDZNGVMJPIREPT7V6HRYX5T3LY/bundle.json","state":"https://pith.science/pith/VDZNGVMJPIREPT7V6HRYX5T3LY/state.json","well_known_bundle":"https://pith.science/.well-known/pith/VDZNGVMJPIREPT7V6HRYX5T3LY/bundle.json"},"state":{"state_type":"pith_open_graph_state","state_version":"1.0","pith_number":"pith:2018:VDZNGVMJPIREPT7V6HRYX5T3LY","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":"4a532c4157b427413f61b6ae5b40d72ad55afe4618fdbd9b9a6bbbb4cd5c57d2","cross_cats_sorted":[],"license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","primary_cat":"astro-ph.GA","submitted_at":"2018-11-09T10:47:25Z","title_canon_sha256":"0f525b4169c2cc744c8bf265c49190db96e99db94aa185d3aec395a18223a7f0"},"schema_version":"1.0","source":{"id":"1811.03856","kind":"arxiv","version":1}},"source_aliases":[{"alias_kind":"arxiv","alias_value":"1811.03856","created_at":"2026-05-17T23:55:43Z"},{"alias_kind":"arxiv_version","alias_value":"1811.03856v1","created_at":"2026-05-17T23:55:43Z"},{"alias_kind":"doi","alias_value":"10.48550/arxiv.1811.03856","created_at":"2026-05-17T23:55:43Z"},{"alias_kind":"pith_short_12","alias_value":"VDZNGVMJPIRE","created_at":"2026-05-18T12:32:59Z"},{"alias_kind":"pith_short_16","alias_value":"VDZNGVMJPIREPT7V","created_at":"2026-05-18T12:32:59Z"},{"alias_kind":"pith_short_8","alias_value":"VDZNGVMJ","created_at":"2026-05-18T12:32:59Z"}],"graph_snapshots":[{"event_id":"sha256:c8fa8ce353ffb3eb8633998e0b25769ef291237b74609fab35e2c8ec7a2c1838","target":"graph","created_at":"2026-05-17T23:55:43Z","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":"Observations of both galaxies in the distant Universe and local starbursts are showing increasing evidence for very hard ionizing spectra that stellar population synthesis models struggle to reproduce. Here we explore the effects of the assumed stellar initial mass function (IMF) on the ionizing photon output of young populations at wavelengths below key ionization energy thresholds. We use a custom set of binary population and spectral synthesis (BPASS) models to explore the effects of IMF assumptions as a function of metallicity, IMF slope, upper mass limit, IMF power law break mass and samp","authors_text":"E. R. Stanway (Warwick), J. J. Eldridge (Auckland)","cross_cats":[],"headline":"","license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","primary_cat":"astro-ph.GA","submitted_at":"2018-11-09T10:47:25Z","title":"Initial Mass Function Variations Cannot Explain the Ionizing Spectrum of Low Metallicity Starbursts"},"references":{"count":0,"internal_anchors":0,"resolved_work":0,"sample":[],"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"source":{"id":"1811.03856","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":"sha256:8a5dab4272764bfd3fae960ed3de1cbaab62e56af6b38151a0925ef31b2e64ca","target":"record","created_at":"2026-05-17T23:55:43Z","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":"4a532c4157b427413f61b6ae5b40d72ad55afe4618fdbd9b9a6bbbb4cd5c57d2","cross_cats_sorted":[],"license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","primary_cat":"astro-ph.GA","submitted_at":"2018-11-09T10:47:25Z","title_canon_sha256":"0f525b4169c2cc744c8bf265c49190db96e99db94aa185d3aec395a18223a7f0"},"schema_version":"1.0","source":{"id":"1811.03856","kind":"arxiv","version":1}},"canonical_sha256":"a8f2d355897a2247cff5f1e38bf67b5e2024eaf7a927668b614a0aa546dff3d0","receipt":{"algorithm":"ed25519","builder_version":"pith-number-builder-2026-05-17-v1","canonical_sha256":"a8f2d355897a2247cff5f1e38bf67b5e2024eaf7a927668b614a0aa546dff3d0","first_computed_at":"2026-05-17T23:55:43.778204Z","key_id":"pith-v1-2026-05","kind":"pith_receipt","last_reissued_at":"2026-05-17T23:55:43.778204Z","public_key_fingerprint":"8d4b5ee74e4693bcd1df2446408b0d54","receipt_version":"0.3","signature_b64":"3h62SIiffg1H9Jp1Z2ZDtuEkMRZu9fpk1A/i/SefD4BhumRlN78yOYPLBPTYTDftcQuEKUaPGXMMM7fUrlkPAw==","signature_status":"signed_v1","signed_at":"2026-05-17T23:55:43.778766Z","signed_message":"canonical_sha256_bytes"},"source_id":"1811.03856","source_kind":"arxiv","source_version":1}}},"equivocations":[],"invalid_events":[],"applied_event_ids":["sha256:8a5dab4272764bfd3fae960ed3de1cbaab62e56af6b38151a0925ef31b2e64ca","sha256:c8fa8ce353ffb3eb8633998e0b25769ef291237b74609fab35e2c8ec7a2c1838"],"state_sha256":"7efc600a385fbe81903267d6aa40606b561d0abe046ec560a33843c0dfe3dab8"},"bundle_signature":{"signature_status":"signed_v1","algorithm":"ed25519","key_id":"pith-v1-2026-05","public_key_fingerprint":"8d4b5ee74e4693bcd1df2446408b0d54","signature_b64":"7hFId+JY5YKHG1WfX+J7iNhhG4F/PXVzfSJNTyylVU3mBs08Zy+WwGqihVyUFn5b5Y+/gmrdRT6hm2TMfVz2DQ==","signed_message":"bundle_sha256_bytes","signed_at":"2026-05-31T12:56:51.700395Z","bundle_sha256":"6250d1d048aacf7388bfbb0e3ca0eeb612178b4dfc5b8c9861d12f1a1951bff6"}}