{"bundle_type":"pith_open_graph_bundle","bundle_version":"1.0","pith_number":"pith:2013:YORIMPWN2PUWZVKP7FKFIW7PUX","short_pith_number":"pith:YORIMPWN","canonical_record":{"source":{"id":"1310.0874","kind":"arxiv","version":1},"metadata":{"license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","primary_cat":"astro-ph.CO","submitted_at":"2013-10-03T01:16:09Z","cross_cats_sorted":[],"title_canon_sha256":"b6d23d0457392a80c0187c0e4117dbce2c8be38540769a9865e44ae6f0e4ce08","abstract_canon_sha256":"604611b192945b47150375134cdb3bdc759f768941182800e261516676aca111"},"schema_version":"1.0"},"canonical_sha256":"c3a2863ecdd3e96cd54ff954545befa5f0f56c870964d52f55694159bafc2d25","source":{"kind":"arxiv","id":"1310.0874","version":1},"source_aliases":[{"alias_kind":"arxiv","alias_value":"1310.0874","created_at":"2026-05-18T01:47:16Z"},{"alias_kind":"arxiv_version","alias_value":"1310.0874v1","created_at":"2026-05-18T01:47:16Z"},{"alias_kind":"doi","alias_value":"10.48550/arxiv.1310.0874","created_at":"2026-05-18T01:47:16Z"},{"alias_kind":"pith_short_12","alias_value":"YORIMPWN2PUW","created_at":"2026-05-18T12:28:06Z"},{"alias_kind":"pith_short_16","alias_value":"YORIMPWN2PUWZVKP","created_at":"2026-05-18T12:28:06Z"},{"alias_kind":"pith_short_8","alias_value":"YORIMPWN","created_at":"2026-05-18T12:28:06Z"}],"events":[{"event_type":"record_created","subject_pith_number":"pith:2013:YORIMPWN2PUWZVKP7FKFIW7PUX","target":"record","payload":{"canonical_record":{"source":{"id":"1310.0874","kind":"arxiv","version":1},"metadata":{"license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","primary_cat":"astro-ph.CO","submitted_at":"2013-10-03T01:16:09Z","cross_cats_sorted":[],"title_canon_sha256":"b6d23d0457392a80c0187c0e4117dbce2c8be38540769a9865e44ae6f0e4ce08","abstract_canon_sha256":"604611b192945b47150375134cdb3bdc759f768941182800e261516676aca111"},"schema_version":"1.0"},"canonical_sha256":"c3a2863ecdd3e96cd54ff954545befa5f0f56c870964d52f55694159bafc2d25","receipt":{"kind":"pith_receipt","key_id":"pith-v1-2026-05","algorithm":"ed25519","signed_at":"2026-05-18T01:47:16.057231Z","signature_b64":"p6cmkCp6PKrs+4y4mBHb+mNByYiou3Pq4I+O3jnnYkjJriuSSij/Lk7cuedC+iRb67aUJhiQ1IrPdygZ6oTnCw==","signed_message":"canonical_sha256_bytes","builder_version":"pith-number-builder-2026-05-17-v1","receipt_version":"0.3","canonical_sha256":"c3a2863ecdd3e96cd54ff954545befa5f0f56c870964d52f55694159bafc2d25","last_reissued_at":"2026-05-18T01:47:16.056532Z","signature_status":"signed_v1","first_computed_at":"2026-05-18T01:47:16.056532Z","public_key_fingerprint":"8d4b5ee74e4693bcd1df2446408b0d54"},"source_kind":"arxiv","source_id":"1310.0874","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":"2026-05-18T01:47:16Z","supersedes":[],"prev_event":null,"signature":{"signature_status":"signed_v1","algorithm":"ed25519","key_id":"pith-v1-2026-05","public_key_fingerprint":"8d4b5ee74e4693bcd1df2446408b0d54","signature_b64":"f80u5o73wDk1Fw1bSEOrpzeVao8OwTuUFsEU+fqEdYNTgZuIKeXmmjoNS+4DDcGgUnz8wfibS1/KN7oSiGL2DA==","signed_message":"open_graph_event_sha256_bytes","signed_at":"2026-05-27T02:13:50.622904Z"},"content_sha256":"39c3c81d3de2e20cd37f564e1f6c0beb31b065f9c9987a2d15f310099a2a7e83","schema_version":"1.0","event_id":"sha256:39c3c81d3de2e20cd37f564e1f6c0beb31b065f9c9987a2d15f310099a2a7e83"},{"event_type":"graph_snapshot","subject_pith_number":"pith:2013:YORIMPWN2PUWZVKP7FKFIW7PUX","target":"graph","payload":{"graph_snapshot":{"paper":{"title":"A Search for Optical Variability of Type 2 Quasars in SDSS Stripe 82","license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","headline":"","cross_cats":[],"primary_cat":"astro-ph.CO","authors_text":"A. J. Barth, A. Voevodkin, D. J. Carson, P. Wo\\'zniak","submitted_at":"2013-10-03T01:16:09Z","abstract_excerpt":"Hundreds of Type 2 quasars have been identified in Sloan Digital Sky Survey (SDSS) data, and there is substantial evidence that they are generally galaxies with highly obscured central engines, in accord with unified models for active galactic nuclei (AGNs). A straightforward expectation of unified models is that highly obscured Type 2 AGNs should show little or no optical variability on timescales of days to years. As a test of this prediction, we have carried out a search for variability in Type 2 quasars in SDSS Stripe 82 using difference-imaging photometry. Starting with the Type 2 AGN cat"},"claims":{"count":0,"items":[],"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"source":{"id":"1310.0874","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":"2026-05-18T01:47:16Z","supersedes":[],"prev_event":null,"signature":{"signature_status":"signed_v1","algorithm":"ed25519","key_id":"pith-v1-2026-05","public_key_fingerprint":"8d4b5ee74e4693bcd1df2446408b0d54","signature_b64":"1gDDGlD+SSfb3bwe1MQ3jDGAThN9sAQKeKJY8/VTUYzzp2ZLXVD5JhVSmWxPwylyk663xba1jScOKFMbERQ5Cg==","signed_message":"open_graph_event_sha256_bytes","signed_at":"2026-05-27T02:13:50.623364Z"},"content_sha256":"d9c7162dbd5b7f1e055f7b3bcff5b71e880f946cef4f779d3d3e000fb35af9fd","schema_version":"1.0","event_id":"sha256:d9c7162dbd5b7f1e055f7b3bcff5b71e880f946cef4f779d3d3e000fb35af9fd"}],"timestamp_proofs":[],"mirror_hints":[{"mirror_type":"https","name":"Pith Resolver","base_url":"https://pith.science","bundle_url":"https://pith.science/pith/YORIMPWN2PUWZVKP7FKFIW7PUX/bundle.json","state_url":"https://pith.science/pith/YORIMPWN2PUWZVKP7FKFIW7PUX/state.json","well_known_bundle_url":"https://pith.science/.well-known/pith/YORIMPWN2PUWZVKP7FKFIW7PUX/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":"2026-05-27T02:13:50Z","links":{"resolver":"https://pith.science/pith/YORIMPWN2PUWZVKP7FKFIW7PUX","bundle":"https://pith.science/pith/YORIMPWN2PUWZVKP7FKFIW7PUX/bundle.json","state":"https://pith.science/pith/YORIMPWN2PUWZVKP7FKFIW7PUX/state.json","well_known_bundle":"https://pith.science/.well-known/pith/YORIMPWN2PUWZVKP7FKFIW7PUX/bundle.json"},"state":{"state_type":"pith_open_graph_state","state_version":"1.0","pith_number":"pith:2013:YORIMPWN2PUWZVKP7FKFIW7PUX","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":"604611b192945b47150375134cdb3bdc759f768941182800e261516676aca111","cross_cats_sorted":[],"license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","primary_cat":"astro-ph.CO","submitted_at":"2013-10-03T01:16:09Z","title_canon_sha256":"b6d23d0457392a80c0187c0e4117dbce2c8be38540769a9865e44ae6f0e4ce08"},"schema_version":"1.0","source":{"id":"1310.0874","kind":"arxiv","version":1}},"source_aliases":[{"alias_kind":"arxiv","alias_value":"1310.0874","created_at":"2026-05-18T01:47:16Z"},{"alias_kind":"arxiv_version","alias_value":"1310.0874v1","created_at":"2026-05-18T01:47:16Z"},{"alias_kind":"doi","alias_value":"10.48550/arxiv.1310.0874","created_at":"2026-05-18T01:47:16Z"},{"alias_kind":"pith_short_12","alias_value":"YORIMPWN2PUW","created_at":"2026-05-18T12:28:06Z"},{"alias_kind":"pith_short_16","alias_value":"YORIMPWN2PUWZVKP","created_at":"2026-05-18T12:28:06Z"},{"alias_kind":"pith_short_8","alias_value":"YORIMPWN","created_at":"2026-05-18T12:28:06Z"}],"graph_snapshots":[{"event_id":"sha256:d9c7162dbd5b7f1e055f7b3bcff5b71e880f946cef4f779d3d3e000fb35af9fd","target":"graph","created_at":"2026-05-18T01:47:16Z","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":"Hundreds of Type 2 quasars have been identified in Sloan Digital Sky Survey (SDSS) data, and there is substantial evidence that they are generally galaxies with highly obscured central engines, in accord with unified models for active galactic nuclei (AGNs). A straightforward expectation of unified models is that highly obscured Type 2 AGNs should show little or no optical variability on timescales of days to years. As a test of this prediction, we have carried out a search for variability in Type 2 quasars in SDSS Stripe 82 using difference-imaging photometry. Starting with the Type 2 AGN cat","authors_text":"A. J. Barth, A. Voevodkin, D. J. Carson, P. Wo\\'zniak","cross_cats":[],"headline":"","license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","primary_cat":"astro-ph.CO","submitted_at":"2013-10-03T01:16:09Z","title":"A Search for Optical Variability of Type 2 Quasars in SDSS Stripe 82"},"references":{"count":0,"internal_anchors":0,"resolved_work":0,"sample":[],"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"source":{"id":"1310.0874","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":"sha256:39c3c81d3de2e20cd37f564e1f6c0beb31b065f9c9987a2d15f310099a2a7e83","target":"record","created_at":"2026-05-18T01:47:16Z","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":"604611b192945b47150375134cdb3bdc759f768941182800e261516676aca111","cross_cats_sorted":[],"license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","primary_cat":"astro-ph.CO","submitted_at":"2013-10-03T01:16:09Z","title_canon_sha256":"b6d23d0457392a80c0187c0e4117dbce2c8be38540769a9865e44ae6f0e4ce08"},"schema_version":"1.0","source":{"id":"1310.0874","kind":"arxiv","version":1}},"canonical_sha256":"c3a2863ecdd3e96cd54ff954545befa5f0f56c870964d52f55694159bafc2d25","receipt":{"algorithm":"ed25519","builder_version":"pith-number-builder-2026-05-17-v1","canonical_sha256":"c3a2863ecdd3e96cd54ff954545befa5f0f56c870964d52f55694159bafc2d25","first_computed_at":"2026-05-18T01:47:16.056532Z","key_id":"pith-v1-2026-05","kind":"pith_receipt","last_reissued_at":"2026-05-18T01:47:16.056532Z","public_key_fingerprint":"8d4b5ee74e4693bcd1df2446408b0d54","receipt_version":"0.3","signature_b64":"p6cmkCp6PKrs+4y4mBHb+mNByYiou3Pq4I+O3jnnYkjJriuSSij/Lk7cuedC+iRb67aUJhiQ1IrPdygZ6oTnCw==","signature_status":"signed_v1","signed_at":"2026-05-18T01:47:16.057231Z","signed_message":"canonical_sha256_bytes"},"source_id":"1310.0874","source_kind":"arxiv","source_version":1}}},"equivocations":[],"invalid_events":[],"applied_event_ids":["sha256:39c3c81d3de2e20cd37f564e1f6c0beb31b065f9c9987a2d15f310099a2a7e83","sha256:d9c7162dbd5b7f1e055f7b3bcff5b71e880f946cef4f779d3d3e000fb35af9fd"],"state_sha256":"15f4fa1fa49df691447ef397a4433c5195c48524314a0aa643901a15c92cdcb9"},"bundle_signature":{"signature_status":"signed_v1","algorithm":"ed25519","key_id":"pith-v1-2026-05","public_key_fingerprint":"8d4b5ee74e4693bcd1df2446408b0d54","signature_b64":"+h1uabSiG8dvNvd5U+/Dh38hlVNXVUPJnHdXjdBQv4KMMSGPwNcn8N5Q8hNBIZEsHd9hUPhkr8VQYxiK6j8OBg==","signed_message":"bundle_sha256_bytes","signed_at":"2026-05-27T02:13:50.626060Z","bundle_sha256":"a3fe5ed801324c33006de404661e2ab194cbaa6f9e5620f11e37f575d423256a"}}