{"bundle_type":"pith_open_graph_bundle","bundle_version":"1.0","pith_number":"pith:2019:JX6NA5WOINFVS3FIUE7AP26UKW","short_pith_number":"pith:JX6NA5WO","canonical_record":{"source":{"id":"1904.03914","kind":"arxiv","version":1},"metadata":{"license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","primary_cat":"astro-ph.GA","submitted_at":"2019-04-08T09:40:24Z","cross_cats_sorted":[],"title_canon_sha256":"23fefd4fcd9d62ec68906a67b4336a802df44b5fc8c9e1411ad77f94907eec98","abstract_canon_sha256":"dfbee412780e37015a1ac511638ba961866401ec4849dcde3faf8b6e32334fa4"},"schema_version":"1.0"},"canonical_sha256":"4dfcd076ce434b596ca8a13e07ebd4558848fa07643144f4a4910f595618cdf6","source":{"kind":"arxiv","id":"1904.03914","version":1},"source_aliases":[{"alias_kind":"arxiv","alias_value":"1904.03914","created_at":"2026-05-17T23:46:11Z"},{"alias_kind":"arxiv_version","alias_value":"1904.03914v1","created_at":"2026-05-17T23:46:11Z"},{"alias_kind":"doi","alias_value":"10.48550/arxiv.1904.03914","created_at":"2026-05-17T23:46:11Z"},{"alias_kind":"pith_short_12","alias_value":"JX6NA5WOINFV","created_at":"2026-05-18T12:33:21Z"},{"alias_kind":"pith_short_16","alias_value":"JX6NA5WOINFVS3FI","created_at":"2026-05-18T12:33:21Z"},{"alias_kind":"pith_short_8","alias_value":"JX6NA5WO","created_at":"2026-05-18T12:33:21Z"}],"events":[{"event_type":"record_created","subject_pith_number":"pith:2019:JX6NA5WOINFVS3FIUE7AP26UKW","target":"record","payload":{"canonical_record":{"source":{"id":"1904.03914","kind":"arxiv","version":1},"metadata":{"license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","primary_cat":"astro-ph.GA","submitted_at":"2019-04-08T09:40:24Z","cross_cats_sorted":[],"title_canon_sha256":"23fefd4fcd9d62ec68906a67b4336a802df44b5fc8c9e1411ad77f94907eec98","abstract_canon_sha256":"dfbee412780e37015a1ac511638ba961866401ec4849dcde3faf8b6e32334fa4"},"schema_version":"1.0"},"canonical_sha256":"4dfcd076ce434b596ca8a13e07ebd4558848fa07643144f4a4910f595618cdf6","receipt":{"kind":"pith_receipt","key_id":"pith-v1-2026-05","algorithm":"ed25519","signed_at":"2026-05-17T23:46:11.820190Z","signature_b64":"lZO/vAIN6O8SkOHlSzMnjf66KUDNtABCNyqCOgzhaLddGCoXX6EEqvtaymAymbNGYNC8nitFqCdXYRXllN7oBw==","signed_message":"canonical_sha256_bytes","builder_version":"pith-number-builder-2026-05-17-v1","receipt_version":"0.3","canonical_sha256":"4dfcd076ce434b596ca8a13e07ebd4558848fa07643144f4a4910f595618cdf6","last_reissued_at":"2026-05-17T23:46:11.819534Z","signature_status":"signed_v1","first_computed_at":"2026-05-17T23:46:11.819534Z","public_key_fingerprint":"8d4b5ee74e4693bcd1df2446408b0d54"},"source_kind":"arxiv","source_id":"1904.03914","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":"2026-05-17T23:46:11Z","supersedes":[],"prev_event":null,"signature":{"signature_status":"signed_v1","algorithm":"ed25519","key_id":"pith-v1-2026-05","public_key_fingerprint":"8d4b5ee74e4693bcd1df2446408b0d54","signature_b64":"DpAHpaWlhUc5wUzdwyClqqaMGZ6PKci8b9fIvpAD0O/tnna6mQsFvCHqUJ7D9ZvJAoIyvFUD1oK+bo9o5hD0AQ==","signed_message":"open_graph_event_sha256_bytes","signed_at":"2026-06-02T04:24:30.569933Z"},"content_sha256":"23d0fbe361e4ba89eec67b8377b4e4c1f929c548e2458bd760cb3ed9897f7e35","schema_version":"1.0","event_id":"sha256:23d0fbe361e4ba89eec67b8377b4e4c1f929c548e2458bd760cb3ed9897f7e35"},{"event_type":"graph_snapshot","subject_pith_number":"pith:2019:JX6NA5WOINFVS3FIUE7AP26UKW","target":"graph","payload":{"graph_snapshot":{"paper":{"title":"Polarization of changing-look quasars","license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","headline":"","cross_cats":[],"primary_cat":"astro-ph.GA","authors_text":"B. Ag\\'is Gonz\\'alez, C. Ramos Almeida, D. Hutsem\\'ekers, D. Sluse, F. Marin, J.-A. Acosta Pulido","submitted_at":"2019-04-08T09:40:24Z","abstract_excerpt":"If the disappearance of the broad emission lines observed in changing-look quasars originates from the obscuration of the quasar core by dusty clouds moving in the torus, high linear optical polarization would be expected in those objects. We then measured the rest-frame UV-blue linear polarization of a sample of 13 changing-look quasars, 7 of them being in a type 1.9-2 state. For all quasars but one the polarization degree is lower than 1%. This suggests that the disappearance of the broad emission lines cannot be attributed to dust obscuration, and supports the scenario in which changes of l"},"claims":{"count":0,"items":[],"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"source":{"id":"1904.03914","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":"2026-05-17T23:46:11Z","supersedes":[],"prev_event":null,"signature":{"signature_status":"signed_v1","algorithm":"ed25519","key_id":"pith-v1-2026-05","public_key_fingerprint":"8d4b5ee74e4693bcd1df2446408b0d54","signature_b64":"Fa8g/RJwyKac180rESRXWLGFyqNMFMgpBvIwYqQg7r2+VWxJC7Gy4YNOnybOFpgpwdqYdzMmYFoyHhMjUY+1Dg==","signed_message":"open_graph_event_sha256_bytes","signed_at":"2026-06-02T04:24:30.570270Z"},"content_sha256":"8521a3119f93a56da8627f77772e18b6c83822a27295fc7cdfd93ffca2376fc1","schema_version":"1.0","event_id":"sha256:8521a3119f93a56da8627f77772e18b6c83822a27295fc7cdfd93ffca2376fc1"}],"timestamp_proofs":[],"mirror_hints":[{"mirror_type":"https","name":"Pith Resolver","base_url":"https://pith.science","bundle_url":"https://pith.science/pith/JX6NA5WOINFVS3FIUE7AP26UKW/bundle.json","state_url":"https://pith.science/pith/JX6NA5WOINFVS3FIUE7AP26UKW/state.json","well_known_bundle_url":"https://pith.science/.well-known/pith/JX6NA5WOINFVS3FIUE7AP26UKW/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":"2026-06-02T04:24:30Z","links":{"resolver":"https://pith.science/pith/JX6NA5WOINFVS3FIUE7AP26UKW","bundle":"https://pith.science/pith/JX6NA5WOINFVS3FIUE7AP26UKW/bundle.json","state":"https://pith.science/pith/JX6NA5WOINFVS3FIUE7AP26UKW/state.json","well_known_bundle":"https://pith.science/.well-known/pith/JX6NA5WOINFVS3FIUE7AP26UKW/bundle.json"},"state":{"state_type":"pith_open_graph_state","state_version":"1.0","pith_number":"pith:2019:JX6NA5WOINFVS3FIUE7AP26UKW","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":"dfbee412780e37015a1ac511638ba961866401ec4849dcde3faf8b6e32334fa4","cross_cats_sorted":[],"license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","primary_cat":"astro-ph.GA","submitted_at":"2019-04-08T09:40:24Z","title_canon_sha256":"23fefd4fcd9d62ec68906a67b4336a802df44b5fc8c9e1411ad77f94907eec98"},"schema_version":"1.0","source":{"id":"1904.03914","kind":"arxiv","version":1}},"source_aliases":[{"alias_kind":"arxiv","alias_value":"1904.03914","created_at":"2026-05-17T23:46:11Z"},{"alias_kind":"arxiv_version","alias_value":"1904.03914v1","created_at":"2026-05-17T23:46:11Z"},{"alias_kind":"doi","alias_value":"10.48550/arxiv.1904.03914","created_at":"2026-05-17T23:46:11Z"},{"alias_kind":"pith_short_12","alias_value":"JX6NA5WOINFV","created_at":"2026-05-18T12:33:21Z"},{"alias_kind":"pith_short_16","alias_value":"JX6NA5WOINFVS3FI","created_at":"2026-05-18T12:33:21Z"},{"alias_kind":"pith_short_8","alias_value":"JX6NA5WO","created_at":"2026-05-18T12:33:21Z"}],"graph_snapshots":[{"event_id":"sha256:8521a3119f93a56da8627f77772e18b6c83822a27295fc7cdfd93ffca2376fc1","target":"graph","created_at":"2026-05-17T23:46:11Z","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":"If the disappearance of the broad emission lines observed in changing-look quasars originates from the obscuration of the quasar core by dusty clouds moving in the torus, high linear optical polarization would be expected in those objects. We then measured the rest-frame UV-blue linear polarization of a sample of 13 changing-look quasars, 7 of them being in a type 1.9-2 state. For all quasars but one the polarization degree is lower than 1%. This suggests that the disappearance of the broad emission lines cannot be attributed to dust obscuration, and supports the scenario in which changes of l","authors_text":"B. Ag\\'is Gonz\\'alez, C. Ramos Almeida, D. Hutsem\\'ekers, D. Sluse, F. Marin, J.-A. Acosta Pulido","cross_cats":[],"headline":"","license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","primary_cat":"astro-ph.GA","submitted_at":"2019-04-08T09:40:24Z","title":"Polarization of changing-look quasars"},"references":{"count":0,"internal_anchors":0,"resolved_work":0,"sample":[],"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"source":{"id":"1904.03914","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":"sha256:23d0fbe361e4ba89eec67b8377b4e4c1f929c548e2458bd760cb3ed9897f7e35","target":"record","created_at":"2026-05-17T23:46:11Z","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":"dfbee412780e37015a1ac511638ba961866401ec4849dcde3faf8b6e32334fa4","cross_cats_sorted":[],"license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","primary_cat":"astro-ph.GA","submitted_at":"2019-04-08T09:40:24Z","title_canon_sha256":"23fefd4fcd9d62ec68906a67b4336a802df44b5fc8c9e1411ad77f94907eec98"},"schema_version":"1.0","source":{"id":"1904.03914","kind":"arxiv","version":1}},"canonical_sha256":"4dfcd076ce434b596ca8a13e07ebd4558848fa07643144f4a4910f595618cdf6","receipt":{"algorithm":"ed25519","builder_version":"pith-number-builder-2026-05-17-v1","canonical_sha256":"4dfcd076ce434b596ca8a13e07ebd4558848fa07643144f4a4910f595618cdf6","first_computed_at":"2026-05-17T23:46:11.819534Z","key_id":"pith-v1-2026-05","kind":"pith_receipt","last_reissued_at":"2026-05-17T23:46:11.819534Z","public_key_fingerprint":"8d4b5ee74e4693bcd1df2446408b0d54","receipt_version":"0.3","signature_b64":"lZO/vAIN6O8SkOHlSzMnjf66KUDNtABCNyqCOgzhaLddGCoXX6EEqvtaymAymbNGYNC8nitFqCdXYRXllN7oBw==","signature_status":"signed_v1","signed_at":"2026-05-17T23:46:11.820190Z","signed_message":"canonical_sha256_bytes"},"source_id":"1904.03914","source_kind":"arxiv","source_version":1}}},"equivocations":[],"invalid_events":[],"applied_event_ids":["sha256:23d0fbe361e4ba89eec67b8377b4e4c1f929c548e2458bd760cb3ed9897f7e35","sha256:8521a3119f93a56da8627f77772e18b6c83822a27295fc7cdfd93ffca2376fc1"],"state_sha256":"3df0a263cb6431957ab6a834c88e2168a07bb8ff2894561b93ef377d61f32b8f"},"bundle_signature":{"signature_status":"signed_v1","algorithm":"ed25519","key_id":"pith-v1-2026-05","public_key_fingerprint":"8d4b5ee74e4693bcd1df2446408b0d54","signature_b64":"LYJvC6SG8s8UE2CKhcwSoVz6dnGzPIUwL6qPONUyz3rnVoCefKE65dW9OrLPxQUyddSVsZXG8sdW6W4PNPIJCA==","signed_message":"bundle_sha256_bytes","signed_at":"2026-06-02T04:24:30.572189Z","bundle_sha256":"b446153eb8e7b5b7633e61a863ca89557a92a281a8575e04c94519a87ace7f56"}}