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    "headline": "A Messier Microwave Sky Barely Moved the Cosmology",
    "slug": "a-messier-microwave-sky-barely-moved-the-cosmology",
    "dek": "Residual foreground power rose 50% over idealized estimates, while 11-parameter uncertainties increased less than 7%.",
    "summary": "Residual foreground power rose 50% over idealized estimates, while 11-parameter uncertainties increased less than 7%.",
    "body_text": "CMB-HD foreground simulations cover 100 square degrees at 2.5-arcsecond resolution and include infrared sources, radio galaxies and galaxy clusters. After source detection and cleaning, residual foreground-plus-noise power at 90 and 148 gigahertz was 50% higher than earlier idealized assumptions. Even so, forecast uncertainties across an 11-parameter cosmology grew by less than 7%, helped by polarization, cross spectra and lensing. The released simulations forecast a proposed survey; they are not observed CMB-HD data.",
    "why_it_matters": "Residual foreground power rose 50% over idealized estimates, while 11-parameter uncertainties increased less than 7%.",
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      "The released simulations forecast a proposed survey; they are not observed CMB-HD data."
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        "qualification": "The released simulations forecast a proposed survey; they are not observed CMB-HD data."
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    "tags": [
      "cosmic microwave background",
      "foregrounds",
      "survey simulation"
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  "sources": [
    {
      "source_id": "source-2026-09-16-021",
      "title": "arXiv preprint 2609.16128",
      "publisher": "arXiv",
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    "title": "A Messier Microwave Sky Barely Moved the Cosmology",
    "publisher": "The Machine Press",
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