{"paper":{"title":"Searching for the Third Wheel: High-Contrast Imaging Constraints on Tertiaries to Black Hole and Neutron Star Binaries","license":"http://creativecommons.org/licenses/by/4.0/","headline":"Deep imaging rules out main-sequence and hot white-dwarf tertiaries to black hole and neutron star binaries at large separations.","cross_cats":["astro-ph.HE"],"primary_cat":"astro-ph.SR","authors_text":"Aniket Sanghi, Kareem El-Badry, Pranav Nagarajan","submitted_at":"2026-05-15T18:00:06Z","abstract_excerpt":"Hierarchical triple evolution provides a promising alternative to isolated binary formation models for black holes (BHs) and neutron stars (NSs) with low-mass stellar companions. To search for tertiaries, we perform deep, adaptive optics-assisted, near-infrared imaging of five quiescent BH low-mass X-ray binaries (LMXBs), Gaia BH1, and twelve Gaia NSs. We detect several faint stars previously unresolved in survey imaging, but none are close enough to robustly rule out a chance alignment. To achieve high contrast sensitivity at close separations, we use the reference star differential imaging s"},"claims":{"count":4,"items":[{"kind":"strongest_claim","text":"We rule out plausible MS tertiaries and young, hot WD tertiaries at projected separations ≳500 au for the Gaia compact object binaries and ≳2000 au for the more distant BH LMXBs.","source":"verdict.strongest_claim","status":"machine_extracted","claim_id":"C1","attestation":"unclaimed"},{"kind":"weakest_assumption","text":"That the injection-recovery tests and contrast curves accurately capture the true sensitivity to bound companions rather than being dominated by residual speckles or unaccounted systematics at the smallest separations.","source":"verdict.weakest_assumption","status":"machine_extracted","claim_id":"C2","attestation":"unclaimed"},{"kind":"one_line_summary","text":"High-contrast imaging of 18 compact-object binaries yields no robust tertiary detections and rules out main-sequence tertiaries at projected separations greater than 500 au for Gaia systems and 2000 au for BH LMXBs.","source":"verdict.one_line_summary","status":"machine_extracted","claim_id":"C3","attestation":"unclaimed"},{"kind":"headline","text":"Deep imaging rules out main-sequence and hot white-dwarf tertiaries to black hole and neutron star binaries at large separations.","source":"verdict.pith_extraction.headline","status":"machine_extracted","claim_id":"C4","attestation":"unclaimed"}],"snapshot_sha256":"69cb4a013d9fcb1671dc6192633a215076647d6eea5a7c0b0e37dfe7609f48d6"},"source":{"id":"2605.16498","kind":"arxiv","version":1},"verdict":{"id":"2dcc6902-c265-4578-bf59-bfeb8b9f9ce0","model_set":{"reader":"grok-4.3"},"created_at":"2026-05-19T21:52:50.180936Z","strongest_claim":"We rule out plausible MS tertiaries and young, hot WD tertiaries at projected separations ≳500 au for the Gaia compact object binaries and ≳2000 au for the more distant BH LMXBs.","one_line_summary":"High-contrast imaging of 18 compact-object binaries yields no robust tertiary detections and rules out main-sequence tertiaries at projected separations greater than 500 au for Gaia systems and 2000 au for BH LMXBs.","pipeline_version":"pith-pipeline@v0.9.0","weakest_assumption":"That the injection-recovery tests and contrast curves accurately capture the true sensitivity to bound companions rather than being dominated by residual speckles or unaccounted systematics at the smallest separations.","pith_extraction_headline":"Deep imaging rules out main-sequence and hot white-dwarf tertiaries to black hole and neutron star binaries at large separations."},"integrity":{"clean":true,"summary":{"advisory":0,"critical":0,"by_detector":{},"informational":0},"endpoint":"/pith/2605.16498/integrity.json","findings":[],"available":true,"detectors_run":[{"name":"doi_compliance","ran_at":"2026-05-19T22:01:30.018305Z","status":"completed","version":"1.0.0","findings_count":0},{"name":"doi_title_agreement","ran_at":"2026-05-19T22:01:23.157195Z","status":"completed","version":"1.0.0","findings_count":0},{"name":"ai_meta_artifact","ran_at":"2026-05-19T19:33:23.099446Z","status":"skipped","version":"1.0.0","findings_count":0},{"name":"claim_evidence","ran_at":"2026-05-19T19:21:57.008458Z","status":"completed","version":"1.0.0","findings_count":0}],"snapshot_sha256":"00ec589b17ea2f4a43db83c53d6995f841295d56a47c6e9b74f1cbd14c37119f"},"references":{"count":81,"sample":[{"doi":"10.1007/s00159-010-0033-1","year":2010,"title":"G., C \\'o rsico , A","work_id":"72daf4bd-03f3-4003-8cd1-71b439f578b9","ref_index":1,"cited_arxiv_id":"","is_internal_anchor":false},{"doi":"10.1093/mnras/stz2335","year":2019,"title":"Atri, P., Miller-Jones, J. C. A., Bahramian, A., et al. 2019, Monthly Notices of the Royal Astronomical Society, 489, 3116, doi: 10.1093/mnras/stz2335","work_id":"9313fb44-37e5-4a4c-95c8-6c6fd35ba5bb","ref_index":2,"cited_arxiv_id":"","is_internal_anchor":false},{"doi":"10.1093/mnrasl/slaa010","year":2020,"title":"Atri, P., Miller-Jones, J. C. A., Bahramian, A., et al. 2020, Modern Notices of the Royal Astronomical Society, 493, L81, doi: 10.1093/mnrasl/slaa010","work_id":"2298982b-ba5a-40ff-8f46-3bdcbac41830","ref_index":3,"cited_arxiv_id":"","is_internal_anchor":false},{"doi":"10.1007/978-981-16-4544-0","year":2023,"title":"doi:10.1007/978-981-16-4544-0\\_151-1","work_id":"63f67c3b-d368-447b-acfd-b25c94055b58","ref_index":4,"cited_arxiv_id":"","is_internal_anchor":false},{"doi":"10.3847/1538-3881/abd806","year":null,"title":"Estimating distances from parallaxes. 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