{"bundle_type":"pith_open_graph_bundle","bundle_version":"1.0","pith_number":"pith:2018:KDSBBQJXEKC5UL7U5IMX5ZZQUA","short_pith_number":"pith:KDSBBQJX","canonical_record":{"source":{"id":"1810.00087","kind":"arxiv","version":2},"metadata":{"license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","primary_cat":"astro-ph.GA","submitted_at":"2018-09-28T21:23:28Z","cross_cats_sorted":[],"title_canon_sha256":"95cc0d0f7500f3e13f055f92655f43ba4b6c1c8f37fbda2fd80e6f171e39dcf1","abstract_canon_sha256":"a78625163e19d88ff501f7dbed35eb2a01d7eec3b8eff0b0454968c557014f3b"},"schema_version":"1.0"},"canonical_sha256":"50e410c1372285da2ff4ea197ee730a027b3a54c485ed7e056514d95771eb7d7","source":{"kind":"arxiv","id":"1810.00087","version":2},"source_aliases":[{"alias_kind":"arxiv","alias_value":"1810.00087","created_at":"2026-05-17T23:50:59Z"},{"alias_kind":"arxiv_version","alias_value":"1810.00087v2","created_at":"2026-05-17T23:50:59Z"},{"alias_kind":"doi","alias_value":"10.48550/arxiv.1810.00087","created_at":"2026-05-17T23:50:59Z"},{"alias_kind":"pith_short_12","alias_value":"KDSBBQJXEKC5","created_at":"2026-05-18T12:32:33Z"},{"alias_kind":"pith_short_16","alias_value":"KDSBBQJXEKC5UL7U","created_at":"2026-05-18T12:32:33Z"},{"alias_kind":"pith_short_8","alias_value":"KDSBBQJX","created_at":"2026-05-18T12:32:33Z"}],"events":[{"event_type":"record_created","subject_pith_number":"pith:2018:KDSBBQJXEKC5UL7U5IMX5ZZQUA","target":"record","payload":{"canonical_record":{"source":{"id":"1810.00087","kind":"arxiv","version":2},"metadata":{"license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","primary_cat":"astro-ph.GA","submitted_at":"2018-09-28T21:23:28Z","cross_cats_sorted":[],"title_canon_sha256":"95cc0d0f7500f3e13f055f92655f43ba4b6c1c8f37fbda2fd80e6f171e39dcf1","abstract_canon_sha256":"a78625163e19d88ff501f7dbed35eb2a01d7eec3b8eff0b0454968c557014f3b"},"schema_version":"1.0"},"canonical_sha256":"50e410c1372285da2ff4ea197ee730a027b3a54c485ed7e056514d95771eb7d7","receipt":{"kind":"pith_receipt","key_id":"pith-v1-2026-05","algorithm":"ed25519","signed_at":"2026-05-17T23:50:59.258855Z","signature_b64":"tcwTXrHtg0LA1nO+QT4uDn2cBy8uta57J8eQWu9huTwYUKzJCZcXNnh07WnNX2DdP5TwU0k6aCPUiIHLkj7aBw==","signed_message":"canonical_sha256_bytes","builder_version":"pith-number-builder-2026-05-17-v1","receipt_version":"0.3","canonical_sha256":"50e410c1372285da2ff4ea197ee730a027b3a54c485ed7e056514d95771eb7d7","last_reissued_at":"2026-05-17T23:50:59.258149Z","signature_status":"signed_v1","first_computed_at":"2026-05-17T23:50:59.258149Z","public_key_fingerprint":"8d4b5ee74e4693bcd1df2446408b0d54"},"source_kind":"arxiv","source_id":"1810.00087","source_version":2,"attestation_state":"computed"},"signer":{"signer_id":"pith.science","signer_type":"pith_registry","key_id":"pith-v1-2026-05","public_key_fingerprint":"8d4b5ee74e4693bcd1df2446408b0d54"},"created_at":"2026-05-17T23:50:59Z","supersedes":[],"prev_event":null,"signature":{"signature_status":"signed_v1","algorithm":"ed25519","key_id":"pith-v1-2026-05","public_key_fingerprint":"8d4b5ee74e4693bcd1df2446408b0d54","signature_b64":"BugoNyLNQQKurBOl+Qp+WtOKoyZpYi7ShXrU2ujLguDQMRtehSf72K+SSqT4F+2OJx6xVI9wi11G8yKTyBD7Cw==","signed_message":"open_graph_event_sha256_bytes","signed_at":"2026-06-23T23:34:55.856901Z"},"content_sha256":"1f0ef0ad360b30f41314c22ebb5095170b4bccf66bf7900a50dc7492717ee21b","schema_version":"1.0","event_id":"sha256:1f0ef0ad360b30f41314c22ebb5095170b4bccf66bf7900a50dc7492717ee21b"},{"event_type":"graph_snapshot","subject_pith_number":"pith:2018:KDSBBQJXEKC5UL7U5IMX5ZZQUA","target":"graph","payload":{"graph_snapshot":{"paper":{"title":"Changing-Look Quasar Candidates: First Results from Follow-up Spectroscopy of Highly Optically Variable Quasars","license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","headline":"","cross_cats":[],"primary_cat":"astro-ph.GA","authors_text":"Alastair Bruce, Amy LeBleu, Andy Lawrence, Chelsea L. MacLeod, Daniel Stern, David Homan, Eugene Magnier, Jessie Runnoe, John J. Ruan, Kenneth C. Chambers, Matthew Graham, Michael Eracleous, Nicholas P. Ross, Nick Kaiser, Nigel Metcalfe, Paul J. Green, Scott F. Anderson, William Burgett","submitted_at":"2018-09-28T21:23:28Z","abstract_excerpt":"Active galactic nuclei (AGN) that show strong rest-frame optical/UV variability in their blue continuum and broad line emission are classified as \"changing-look\" AGN, or at higher luminosities changing look quasars (CLQs). These surprisingly large and sometimes rapid transitions challenge accepted models of quasar physics and duty cycles, offer several new avenues for study of quasar host galaxies, and open a wider interpretation of the cause of differences between broad and narrow line AGN. To better characterize extreme quasar variability, we present follow-up spectroscopy as part of a compr"},"claims":{"count":0,"items":[],"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"source":{"id":"1810.00087","kind":"arxiv","version":2},"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":"2026-05-17T23:50:59Z","supersedes":[],"prev_event":null,"signature":{"signature_status":"signed_v1","algorithm":"ed25519","key_id":"pith-v1-2026-05","public_key_fingerprint":"8d4b5ee74e4693bcd1df2446408b0d54","signature_b64":"GvbicWTgTpFuwoGommaXc0Rt5MLtzezSd8N3NFznol8L+5ew3PjORzjZj/QiVsoVgWccHfaPg0mN/hH5YJR7Cg==","signed_message":"open_graph_event_sha256_bytes","signed_at":"2026-06-23T23:34:55.857234Z"},"content_sha256":"16e66e92356a7357d5816b19cba4d97b9bb769070f47c41fa1c45c82b49eca77","schema_version":"1.0","event_id":"sha256:16e66e92356a7357d5816b19cba4d97b9bb769070f47c41fa1c45c82b49eca77"}],"timestamp_proofs":[],"mirror_hints":[{"mirror_type":"https","name":"Pith Resolver","base_url":"https://pith.science","bundle_url":"https://pith.science/pith/KDSBBQJXEKC5UL7U5IMX5ZZQUA/bundle.json","state_url":"https://pith.science/pith/KDSBBQJXEKC5UL7U5IMX5ZZQUA/state.json","well_known_bundle_url":"https://pith.science/.well-known/pith/KDSBBQJXEKC5UL7U5IMX5ZZQUA/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":"2026-06-23T23:34:55Z","links":{"resolver":"https://pith.science/pith/KDSBBQJXEKC5UL7U5IMX5ZZQUA","bundle":"https://pith.science/pith/KDSBBQJXEKC5UL7U5IMX5ZZQUA/bundle.json","state":"https://pith.science/pith/KDSBBQJXEKC5UL7U5IMX5ZZQUA/state.json","well_known_bundle":"https://pith.science/.well-known/pith/KDSBBQJXEKC5UL7U5IMX5ZZQUA/bundle.json"},"state":{"state_type":"pith_open_graph_state","state_version":"1.0","pith_number":"pith:2018:KDSBBQJXEKC5UL7U5IMX5ZZQUA","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":"a78625163e19d88ff501f7dbed35eb2a01d7eec3b8eff0b0454968c557014f3b","cross_cats_sorted":[],"license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","primary_cat":"astro-ph.GA","submitted_at":"2018-09-28T21:23:28Z","title_canon_sha256":"95cc0d0f7500f3e13f055f92655f43ba4b6c1c8f37fbda2fd80e6f171e39dcf1"},"schema_version":"1.0","source":{"id":"1810.00087","kind":"arxiv","version":2}},"source_aliases":[{"alias_kind":"arxiv","alias_value":"1810.00087","created_at":"2026-05-17T23:50:59Z"},{"alias_kind":"arxiv_version","alias_value":"1810.00087v2","created_at":"2026-05-17T23:50:59Z"},{"alias_kind":"doi","alias_value":"10.48550/arxiv.1810.00087","created_at":"2026-05-17T23:50:59Z"},{"alias_kind":"pith_short_12","alias_value":"KDSBBQJXEKC5","created_at":"2026-05-18T12:32:33Z"},{"alias_kind":"pith_short_16","alias_value":"KDSBBQJXEKC5UL7U","created_at":"2026-05-18T12:32:33Z"},{"alias_kind":"pith_short_8","alias_value":"KDSBBQJX","created_at":"2026-05-18T12:32:33Z"}],"graph_snapshots":[{"event_id":"sha256:16e66e92356a7357d5816b19cba4d97b9bb769070f47c41fa1c45c82b49eca77","target":"graph","created_at":"2026-05-17T23:50:59Z","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":"Active galactic nuclei (AGN) that show strong rest-frame optical/UV variability in their blue continuum and broad line emission are classified as \"changing-look\" AGN, or at higher luminosities changing look quasars (CLQs). These surprisingly large and sometimes rapid transitions challenge accepted models of quasar physics and duty cycles, offer several new avenues for study of quasar host galaxies, and open a wider interpretation of the cause of differences between broad and narrow line AGN. To better characterize extreme quasar variability, we present follow-up spectroscopy as part of a compr","authors_text":"Alastair Bruce, Amy LeBleu, Andy Lawrence, Chelsea L. MacLeod, Daniel Stern, David Homan, Eugene Magnier, Jessie Runnoe, John J. Ruan, Kenneth C. Chambers, Matthew Graham, Michael Eracleous, Nicholas P. Ross, Nick Kaiser, Nigel Metcalfe, Paul J. Green, Scott F. Anderson, William Burgett","cross_cats":[],"headline":"","license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","primary_cat":"astro-ph.GA","submitted_at":"2018-09-28T21:23:28Z","title":"Changing-Look Quasar Candidates: First Results from Follow-up Spectroscopy of Highly Optically Variable Quasars"},"references":{"count":0,"internal_anchors":0,"resolved_work":0,"sample":[],"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"source":{"id":"1810.00087","kind":"arxiv","version":2},"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":"sha256:1f0ef0ad360b30f41314c22ebb5095170b4bccf66bf7900a50dc7492717ee21b","target":"record","created_at":"2026-05-17T23:50:59Z","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":"a78625163e19d88ff501f7dbed35eb2a01d7eec3b8eff0b0454968c557014f3b","cross_cats_sorted":[],"license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","primary_cat":"astro-ph.GA","submitted_at":"2018-09-28T21:23:28Z","title_canon_sha256":"95cc0d0f7500f3e13f055f92655f43ba4b6c1c8f37fbda2fd80e6f171e39dcf1"},"schema_version":"1.0","source":{"id":"1810.00087","kind":"arxiv","version":2}},"canonical_sha256":"50e410c1372285da2ff4ea197ee730a027b3a54c485ed7e056514d95771eb7d7","receipt":{"algorithm":"ed25519","builder_version":"pith-number-builder-2026-05-17-v1","canonical_sha256":"50e410c1372285da2ff4ea197ee730a027b3a54c485ed7e056514d95771eb7d7","first_computed_at":"2026-05-17T23:50:59.258149Z","key_id":"pith-v1-2026-05","kind":"pith_receipt","last_reissued_at":"2026-05-17T23:50:59.258149Z","public_key_fingerprint":"8d4b5ee74e4693bcd1df2446408b0d54","receipt_version":"0.3","signature_b64":"tcwTXrHtg0LA1nO+QT4uDn2cBy8uta57J8eQWu9huTwYUKzJCZcXNnh07WnNX2DdP5TwU0k6aCPUiIHLkj7aBw==","signature_status":"signed_v1","signed_at":"2026-05-17T23:50:59.258855Z","signed_message":"canonical_sha256_bytes"},"source_id":"1810.00087","source_kind":"arxiv","source_version":2}}},"equivocations":[],"invalid_events":[],"applied_event_ids":["sha256:1f0ef0ad360b30f41314c22ebb5095170b4bccf66bf7900a50dc7492717ee21b","sha256:16e66e92356a7357d5816b19cba4d97b9bb769070f47c41fa1c45c82b49eca77"],"state_sha256":"4051a5d094075d7bbda61213c82382d7152470c7cb9fe31273a92ad59cc8579a"},"bundle_signature":{"signature_status":"signed_v1","algorithm":"ed25519","key_id":"pith-v1-2026-05","public_key_fingerprint":"8d4b5ee74e4693bcd1df2446408b0d54","signature_b64":"f39w0ckl6dZmtUsWRMErhtBg8nDNKxv9DSAnaZJz/aHkk38mHHm7YDC05NHLa9dRnsyEEhwaAvzSEOhIRo+UCw==","signed_message":"bundle_sha256_bytes","signed_at":"2026-06-23T23:34:55.859195Z","bundle_sha256":"bede85a6c207e199184ad44c19607ee78f9646060596ea07594aee857832fe06"}}