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    "headline": "Three Long Microlensing Events Were Not Black Holes",
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    "dek": "A decade of photometry plus Keck astrometry narrowed four candidate lenses.",
    "summary": "A decade of photometry plus Keck astrometry narrowed four candidate lenses.",
    "body_text": "A search combined ten years of OGLE and MOA photometry with adaptive-optics measurements from Keck to estimate four long-duration microlensing lens masses. Three candidates were ruled out as black holes and are more likely stars or white dwarfs. Across this and earlier work, one of six events is confirmed as a black hole and a second remains possible. The small sample agrees with current Galactic simulations but is too limited to pin down black-hole formation rates.",
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    "tags": [
      "microlensing",
      "stellar black holes",
      "Keck"
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  "sources": [
    {
      "source_id": "source-2026-09-24-012",
      "title": "arXiv preprint 2609.28420",
      "publisher": "arXiv",
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      "published_at": "2026-09-23T13:25:35.000-04:00",
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    "name": "The Machine Press",
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    "title": "Three Long Microlensing Events Were Not Black Holes",
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    "published_at": "2026-09-24T09:00:00.000-04:00",
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