{"record_type":"pith_number_record","schema_url":"https://pith.science/schemas/pith-number/v1.json","pith_number":"pith:2019:TDJ52WHVJFRZG2JTAL27NEJDWI","short_pith_number":"pith:TDJ52WHV","schema_version":"1.0","canonical_sha256":"98d3dd58f5496393693302f5f69123b23fd67e4e389161cee138284d8ba6f706","source":{"kind":"arxiv","id":"1902.10496","version":1},"attestation_state":"computed","paper":{"title":"X-ray binaries as the origin of nebular HeII emission in low-metallicity star-forming galaxies","license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","headline":"","cross_cats":[],"primary_cat":"astro-ph.GA","authors_text":"2), (2) CNRS, (3) Bogolyubov Institute for Theoretical Physics, D. Schaerer (1, Kiev), T. Fragos (2), Y. Izotov (3) ((1) University of Geneva","submitted_at":"2019-02-27T12:54:14Z","abstract_excerpt":"The origin of nebular HeII emission, which is frequently observed in low-metallicity (O/H) star-forming galaxies, remains largely an unsolved question. Using the observed anticorrelation of the integrated X-ray luminosity per unit of star formation rate ($L_X/{\\rm SFR}$) of an X-ray binary population with metallicity and other empirical data from the well-studied galaxy I Zw 18, we show that the observed HeII 4686 intensity and its trend with metallicity is naturally reproduced if the bulk of He$^+$ ionizing photons are emitted by the X-ray sources. We also show that a combination of X-ray bin"},"verification_status":{"content_addressed":true,"pith_receipt":true,"author_attested":false,"weak_author_claims":0,"strong_author_claims":0,"externally_anchored":false,"storage_verified":false,"citation_signatures":0,"replication_records":0,"graph_snapshot":true,"references_resolved":false,"formal_links_present":false},"canonical_record":{"source":{"id":"1902.10496","kind":"arxiv","version":1},"metadata":{"license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","primary_cat":"astro-ph.GA","submitted_at":"2019-02-27T12:54:14Z","cross_cats_sorted":[],"title_canon_sha256":"658bfe1eaa24881aa371f386444d04376fc18afd532dd054e6fd237a3c794a1e","abstract_canon_sha256":"d6b6674ea601eb29e26a946b17bb856a4087fa5fea426889b5d511149e29b60f"},"schema_version":"1.0"},"receipt":{"kind":"pith_receipt","key_id":"pith-v1-2026-05","algorithm":"ed25519","signed_at":"2026-05-17T23:52:30.730281Z","signature_b64":"OWgkITaiChDsKyK1v6nxbQqzO7NcYtBuoVZsoQw7//crilJD5yj7IHG0FZyc7gRzSB1P9xaMm6gETaU/nbz0Cg==","signed_message":"canonical_sha256_bytes","builder_version":"pith-number-builder-2026-05-17-v1","receipt_version":"0.3","canonical_sha256":"98d3dd58f5496393693302f5f69123b23fd67e4e389161cee138284d8ba6f706","last_reissued_at":"2026-05-17T23:52:30.729845Z","signature_status":"signed_v1","first_computed_at":"2026-05-17T23:52:30.729845Z","public_key_fingerprint":"8d4b5ee74e4693bcd1df2446408b0d54"},"graph_snapshot":{"paper":{"title":"X-ray binaries as the origin of nebular HeII emission in low-metallicity star-forming galaxies","license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","headline":"","cross_cats":[],"primary_cat":"astro-ph.GA","authors_text":"2), (2) CNRS, (3) Bogolyubov Institute for Theoretical Physics, D. Schaerer (1, Kiev), T. Fragos (2), Y. Izotov (3) ((1) University of Geneva","submitted_at":"2019-02-27T12:54:14Z","abstract_excerpt":"The origin of nebular HeII emission, which is frequently observed in low-metallicity (O/H) star-forming galaxies, remains largely an unsolved question. Using the observed anticorrelation of the integrated X-ray luminosity per unit of star formation rate ($L_X/{\\rm SFR}$) of an X-ray binary population with metallicity and other empirical data from the well-studied galaxy I Zw 18, we show that the observed HeII 4686 intensity and its trend with metallicity is naturally reproduced if the bulk of He$^+$ ionizing photons are emitted by the X-ray sources. We also show that a combination of X-ray bin"},"claims":{"count":0,"items":[],"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"source":{"id":"1902.10496","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"},"aliases":[{"alias_kind":"arxiv","alias_value":"1902.10496","created_at":"2026-05-17T23:52:30.729916+00:00"},{"alias_kind":"arxiv_version","alias_value":"1902.10496v1","created_at":"2026-05-17T23:52:30.729916+00:00"},{"alias_kind":"doi","alias_value":"10.48550/arxiv.1902.10496","created_at":"2026-05-17T23:52:30.729916+00:00"},{"alias_kind":"pith_short_12","alias_value":"TDJ52WHVJFRZ","created_at":"2026-05-18T12:33:27.125529+00:00"},{"alias_kind":"pith_short_16","alias_value":"TDJ52WHVJFRZG2JT","created_at":"2026-05-18T12:33:27.125529+00:00"},{"alias_kind":"pith_short_8","alias_value":"TDJ52WHV","created_at":"2026-05-18T12:33:27.125529+00:00"}],"events":[],"event_summary":{},"paper_claims":[],"inbound_citations":{"count":0,"internal_anchor_count":0,"sample":[]},"formal_canon":{"evidence_count":0,"sample":[],"anchors":[]},"links":{"html":"https://pith.science/pith/TDJ52WHVJFRZG2JTAL27NEJDWI","json":"https://pith.science/pith/TDJ52WHVJFRZG2JTAL27NEJDWI.json","graph_json":"https://pith.science/api/pith-number/TDJ52WHVJFRZG2JTAL27NEJDWI/graph.json","events_json":"https://pith.science/api/pith-number/TDJ52WHVJFRZG2JTAL27NEJDWI/events.json","paper":"https://pith.science/paper/TDJ52WHV"},"agent_actions":{"view_html":"https://pith.science/pith/TDJ52WHVJFRZG2JTAL27NEJDWI","download_json":"https://pith.science/pith/TDJ52WHVJFRZG2JTAL27NEJDWI.json","view_paper":"https://pith.science/paper/TDJ52WHV","resolve_alias":"https://pith.science/api/pith-number/resolve?arxiv=1902.10496&json=true","fetch_graph":"https://pith.science/api/pith-number/TDJ52WHVJFRZG2JTAL27NEJDWI/graph.json","fetch_events":"https://pith.science/api/pith-number/TDJ52WHVJFRZG2JTAL27NEJDWI/events.json","actions":{"anchor_timestamp":"https://pith.science/pith/TDJ52WHVJFRZG2JTAL27NEJDWI/action/timestamp_anchor","attest_storage":"https://pith.science/pith/TDJ52WHVJFRZG2JTAL27NEJDWI/action/storage_attestation","attest_author":"https://pith.science/pith/TDJ52WHVJFRZG2JTAL27NEJDWI/action/author_attestation","sign_citation":"https://pith.science/pith/TDJ52WHVJFRZG2JTAL27NEJDWI/action/citation_signature","submit_replication":"https://pith.science/pith/TDJ52WHVJFRZG2JTAL27NEJDWI/action/replication_record"}},"created_at":"2026-05-17T23:52:30.729916+00:00","updated_at":"2026-05-17T23:52:30.729916+00:00"}