{"bundle_type":"pith_open_graph_bundle","bundle_version":"1.0","pith_number":"pith:2016:NEKSMF2HPGAVNIPIP7VMN6K7VF","short_pith_number":"pith:NEKSMF2H","canonical_record":{"source":{"id":"1601.02638","kind":"arxiv","version":1},"metadata":{"license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","primary_cat":"astro-ph.HE","submitted_at":"2016-01-11T21:02:53Z","cross_cats_sorted":[],"title_canon_sha256":"c40ce6f31e87c30ed2c631ec9753116bc6ad880a5066df9275fa6be501a6cdcc","abstract_canon_sha256":"8e79e8e068309e58f8c1f21858f7b94f3e1f9ccb48a5f76d8f38ffa6f463a361"},"schema_version":"1.0"},"canonical_sha256":"6915261747798156a1e87feac6f95fa96d891263216650b1e44ae74eb5345d2d","source":{"kind":"arxiv","id":"1601.02638","version":1},"source_aliases":[{"alias_kind":"arxiv","alias_value":"1601.02638","created_at":"2026-05-18T01:20:40Z"},{"alias_kind":"arxiv_version","alias_value":"1601.02638v1","created_at":"2026-05-18T01:20:40Z"},{"alias_kind":"doi","alias_value":"10.48550/arxiv.1601.02638","created_at":"2026-05-18T01:20:40Z"},{"alias_kind":"pith_short_12","alias_value":"NEKSMF2HPGAV","created_at":"2026-05-18T12:30:32Z"},{"alias_kind":"pith_short_16","alias_value":"NEKSMF2HPGAVNIPI","created_at":"2026-05-18T12:30:32Z"},{"alias_kind":"pith_short_8","alias_value":"NEKSMF2H","created_at":"2026-05-18T12:30:32Z"}],"events":[{"event_type":"record_created","subject_pith_number":"pith:2016:NEKSMF2HPGAVNIPIP7VMN6K7VF","target":"record","payload":{"canonical_record":{"source":{"id":"1601.02638","kind":"arxiv","version":1},"metadata":{"license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","primary_cat":"astro-ph.HE","submitted_at":"2016-01-11T21:02:53Z","cross_cats_sorted":[],"title_canon_sha256":"c40ce6f31e87c30ed2c631ec9753116bc6ad880a5066df9275fa6be501a6cdcc","abstract_canon_sha256":"8e79e8e068309e58f8c1f21858f7b94f3e1f9ccb48a5f76d8f38ffa6f463a361"},"schema_version":"1.0"},"canonical_sha256":"6915261747798156a1e87feac6f95fa96d891263216650b1e44ae74eb5345d2d","receipt":{"kind":"pith_receipt","key_id":"pith-v1-2026-05","algorithm":"ed25519","signed_at":"2026-05-18T01:20:40.339635Z","signature_b64":"v2BAgra3xpjvot28Gw4gfDZAgcVp2akYghw+Txqi17JWwHf8Ssy0KEVwFIStoSAuPFzq2naAEDD7cy++QONvDg==","signed_message":"canonical_sha256_bytes","builder_version":"pith-number-builder-2026-05-17-v1","receipt_version":"0.3","canonical_sha256":"6915261747798156a1e87feac6f95fa96d891263216650b1e44ae74eb5345d2d","last_reissued_at":"2026-05-18T01:20:40.338835Z","signature_status":"signed_v1","first_computed_at":"2026-05-18T01:20:40.338835Z","public_key_fingerprint":"8d4b5ee74e4693bcd1df2446408b0d54"},"source_kind":"arxiv","source_id":"1601.02638","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":"2026-05-18T01:20:40Z","supersedes":[],"prev_event":null,"signature":{"signature_status":"signed_v1","algorithm":"ed25519","key_id":"pith-v1-2026-05","public_key_fingerprint":"8d4b5ee74e4693bcd1df2446408b0d54","signature_b64":"qFMbpn+GmHlQYXln/PSJ/nPUostIw1H6rch0FEVmxH4/QIqtSOno+qF4lFDoHF14VI/OSdw9lDe5dIibuUKHDw==","signed_message":"open_graph_event_sha256_bytes","signed_at":"2026-05-25T12:39:51.512306Z"},"content_sha256":"79f07ff289d0d423e071177421426a7ffca6e4919c84233eecbaa4a30589c6a5","schema_version":"1.0","event_id":"sha256:79f07ff289d0d423e071177421426a7ffca6e4919c84233eecbaa4a30589c6a5"},{"event_type":"graph_snapshot","subject_pith_number":"pith:2016:NEKSMF2HPGAVNIPIP7VMN6K7VF","target":"graph","payload":{"graph_snapshot":{"paper":{"title":"First Search for an X-ray -- Optical Reverberation Signal in an Ultraluminous X-ray Source","license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","headline":"","cross_cats":[],"primary_cat":"astro-ph.HE","authors_text":"Dheeraj R. Pasham (NASA/GSFC & JSI), Margaret L. Trippe, Poshak Gandhi, Richard F. Mushotzky, S. Bradley Cenko, Tod E. Strohmayer","submitted_at":"2016-01-11T21:02:53Z","abstract_excerpt":"Using simultaneous optical (VLT/FORS2) and X-ray (XMM-Newton) data of NGC 5408, we present the first ever attempt to search for a reverberation signal in an ultraluminous X-ray source (NGC 5408 X-1). The idea is similar to AGN broad line reverberation mapping where a lag measurement between the X-ray and the optical flux combined with a Keplerian velocity estimate should enable us to weigh the central compact object. We find that although NGC 5408 X-1's X-rays are variable on a timescale of a few hundred seconds (RMS of 9.0$\\pm$0.5%), the optical emission does not show any statistically signif"},"claims":{"count":0,"items":[],"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"source":{"id":"1601.02638","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":"2026-05-18T01:20:40Z","supersedes":[],"prev_event":null,"signature":{"signature_status":"signed_v1","algorithm":"ed25519","key_id":"pith-v1-2026-05","public_key_fingerprint":"8d4b5ee74e4693bcd1df2446408b0d54","signature_b64":"7bvSLNm+WHsxXRSRXsDd60zprzHiKHHJ7u1zTaosGx8L7KXGQoy9IGRtCZfaH2w+sM+lNNjSktp91+LzIaZJDQ==","signed_message":"open_graph_event_sha256_bytes","signed_at":"2026-05-25T12:39:51.512971Z"},"content_sha256":"12e839214c2391ca664fc9e048b89327a1614877961b6d8c9fcb9616eeb2110d","schema_version":"1.0","event_id":"sha256:12e839214c2391ca664fc9e048b89327a1614877961b6d8c9fcb9616eeb2110d"}],"timestamp_proofs":[],"mirror_hints":[{"mirror_type":"https","name":"Pith Resolver","base_url":"https://pith.science","bundle_url":"https://pith.science/pith/NEKSMF2HPGAVNIPIP7VMN6K7VF/bundle.json","state_url":"https://pith.science/pith/NEKSMF2HPGAVNIPIP7VMN6K7VF/state.json","well_known_bundle_url":"https://pith.science/.well-known/pith/NEKSMF2HPGAVNIPIP7VMN6K7VF/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":"2026-05-25T12:39:51Z","links":{"resolver":"https://pith.science/pith/NEKSMF2HPGAVNIPIP7VMN6K7VF","bundle":"https://pith.science/pith/NEKSMF2HPGAVNIPIP7VMN6K7VF/bundle.json","state":"https://pith.science/pith/NEKSMF2HPGAVNIPIP7VMN6K7VF/state.json","well_known_bundle":"https://pith.science/.well-known/pith/NEKSMF2HPGAVNIPIP7VMN6K7VF/bundle.json"},"state":{"state_type":"pith_open_graph_state","state_version":"1.0","pith_number":"pith:2016:NEKSMF2HPGAVNIPIP7VMN6K7VF","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":"8e79e8e068309e58f8c1f21858f7b94f3e1f9ccb48a5f76d8f38ffa6f463a361","cross_cats_sorted":[],"license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","primary_cat":"astro-ph.HE","submitted_at":"2016-01-11T21:02:53Z","title_canon_sha256":"c40ce6f31e87c30ed2c631ec9753116bc6ad880a5066df9275fa6be501a6cdcc"},"schema_version":"1.0","source":{"id":"1601.02638","kind":"arxiv","version":1}},"source_aliases":[{"alias_kind":"arxiv","alias_value":"1601.02638","created_at":"2026-05-18T01:20:40Z"},{"alias_kind":"arxiv_version","alias_value":"1601.02638v1","created_at":"2026-05-18T01:20:40Z"},{"alias_kind":"doi","alias_value":"10.48550/arxiv.1601.02638","created_at":"2026-05-18T01:20:40Z"},{"alias_kind":"pith_short_12","alias_value":"NEKSMF2HPGAV","created_at":"2026-05-18T12:30:32Z"},{"alias_kind":"pith_short_16","alias_value":"NEKSMF2HPGAVNIPI","created_at":"2026-05-18T12:30:32Z"},{"alias_kind":"pith_short_8","alias_value":"NEKSMF2H","created_at":"2026-05-18T12:30:32Z"}],"graph_snapshots":[{"event_id":"sha256:12e839214c2391ca664fc9e048b89327a1614877961b6d8c9fcb9616eeb2110d","target":"graph","created_at":"2026-05-18T01:20:40Z","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":"Using simultaneous optical (VLT/FORS2) and X-ray (XMM-Newton) data of NGC 5408, we present the first ever attempt to search for a reverberation signal in an ultraluminous X-ray source (NGC 5408 X-1). The idea is similar to AGN broad line reverberation mapping where a lag measurement between the X-ray and the optical flux combined with a Keplerian velocity estimate should enable us to weigh the central compact object. We find that although NGC 5408 X-1's X-rays are variable on a timescale of a few hundred seconds (RMS of 9.0$\\pm$0.5%), the optical emission does not show any statistically signif","authors_text":"Dheeraj R. Pasham (NASA/GSFC & JSI), Margaret L. Trippe, Poshak Gandhi, Richard F. Mushotzky, S. Bradley Cenko, Tod E. Strohmayer","cross_cats":[],"headline":"","license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","primary_cat":"astro-ph.HE","submitted_at":"2016-01-11T21:02:53Z","title":"First Search for an X-ray -- Optical Reverberation Signal in an Ultraluminous X-ray Source"},"references":{"count":0,"internal_anchors":0,"resolved_work":0,"sample":[],"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"source":{"id":"1601.02638","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":"sha256:79f07ff289d0d423e071177421426a7ffca6e4919c84233eecbaa4a30589c6a5","target":"record","created_at":"2026-05-18T01:20:40Z","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":"8e79e8e068309e58f8c1f21858f7b94f3e1f9ccb48a5f76d8f38ffa6f463a361","cross_cats_sorted":[],"license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","primary_cat":"astro-ph.HE","submitted_at":"2016-01-11T21:02:53Z","title_canon_sha256":"c40ce6f31e87c30ed2c631ec9753116bc6ad880a5066df9275fa6be501a6cdcc"},"schema_version":"1.0","source":{"id":"1601.02638","kind":"arxiv","version":1}},"canonical_sha256":"6915261747798156a1e87feac6f95fa96d891263216650b1e44ae74eb5345d2d","receipt":{"algorithm":"ed25519","builder_version":"pith-number-builder-2026-05-17-v1","canonical_sha256":"6915261747798156a1e87feac6f95fa96d891263216650b1e44ae74eb5345d2d","first_computed_at":"2026-05-18T01:20:40.338835Z","key_id":"pith-v1-2026-05","kind":"pith_receipt","last_reissued_at":"2026-05-18T01:20:40.338835Z","public_key_fingerprint":"8d4b5ee74e4693bcd1df2446408b0d54","receipt_version":"0.3","signature_b64":"v2BAgra3xpjvot28Gw4gfDZAgcVp2akYghw+Txqi17JWwHf8Ssy0KEVwFIStoSAuPFzq2naAEDD7cy++QONvDg==","signature_status":"signed_v1","signed_at":"2026-05-18T01:20:40.339635Z","signed_message":"canonical_sha256_bytes"},"source_id":"1601.02638","source_kind":"arxiv","source_version":1}}},"equivocations":[],"invalid_events":[],"applied_event_ids":["sha256:79f07ff289d0d423e071177421426a7ffca6e4919c84233eecbaa4a30589c6a5","sha256:12e839214c2391ca664fc9e048b89327a1614877961b6d8c9fcb9616eeb2110d"],"state_sha256":"63dc0d04e3daf3bd9707fc56ff632b48b1cd8bff4dd8d47121a2adc9d5618809"},"bundle_signature":{"signature_status":"signed_v1","algorithm":"ed25519","key_id":"pith-v1-2026-05","public_key_fingerprint":"8d4b5ee74e4693bcd1df2446408b0d54","signature_b64":"auZg/WNOXCQ8/UtTDa2Ethz/unYQuofvYwiiWk40Hx10NBeubIWPz6Ze2EIsu+3jdrf8C1h6pPg8O0LWpMptBw==","signed_message":"bundle_sha256_bytes","signed_at":"2026-05-25T12:39:51.516519Z","bundle_sha256":"5117337c721a2f9c63722d0fa6a7ad805d57563987cedcba8b4194319627a86b"}}