{
  "abstract": "We present the first detection of the cosmological 21 cm intensity mapping signal in autocorrelation at z ∼ 1 with the Canadian Hydrogen Intensity Mapping Experiment (CHIME). Using 94 nights of observation, we have measured the 21 cm auto power spectrum over a frequency range of 608.2–707.8 MHz ( z = 1.34–1.01) at 0.4 h Mpc −1 ≲ k ≲ 1.5 h Mpc −1 , with a detection significance of 12.4 σ . Our analysis employs significant improvements to the CHIME data processing pipeline compared to previous work, including novel radio frequency interference detection and masking algorithms, achromatic beamforming techniques, and foreground filtering before time averaging to minimize spectral leakage. We establish the robustness and reliability of our detection through a comprehensive suite of validation tests. We also measure the 21 cm signal in two independent sub-bands centered at z ∼ 1.08 and z ∼ 1.24 with detection significance of 8.6 σ and 9.1 σ , respectively. We briefly discuss the theoretical interpretation of these measurements in terms of a power spectrum model, deferring the details to a companion paper. This auto power spectrum detection demonstrates CHIME’s capability to probe large-scale structure through 21 cm intensity mapping without reliance on external galaxy surveys.",
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  "affiliations": [
    "University of British Columbia",
    "West Virginia University",
    "McGill University",
    "Arizona State University",
    "Herzberg Astronomy & Astrophysics Research Centre",
    "University of British Columbia-Okanagan",
    "University of Groningen",
    "Canadian Institute for Theoretical Astrophysics",
    "The Netherlands Institute for Radio Astronomy",
    "MIT Kavli Institute for Astrophysics and Space Research",
    "Massachusetts Institute of Technology",
    "University of Toronto",
    "Yale University",
    "University of Western Ontario",
    "Canadian Institute for Advanced Research",
    "Institute of Astronomy and Astrophysics",
    "Perimeter Institute for Theoretical Physics",
    "Kavli Institute for Particle Astrophysics and Cosmology",
    "SLAC National Accelerator Laboratory",
    "SKA Observatory, Science Operations Centre",
    "Raman Research Institute"
  ],
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  "author_total": 38,
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      "name": "Mandana Amiri",
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      "name": "Arnab Chakraborty",
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      "name": "Jean-François Cliche",
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      "name": "M. Dobbs",
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      "name": "Simon Foreman",
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      "name": "Liam Gray",
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      "name": "Alex S. Hill",
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      "name": "Gary F. Hinshaw",
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      "name": "C. Höfer",
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      "name": "Albin Joseph",
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      "name": "Nolan Kruger",
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      "name": "T. L. Landecker",
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        8
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      "name": "Rik van Lieshout",
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      "name": "Joshua MacEachern",
      "orcid": "0000-0001-8064-6116"
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      "name": "Kiyoshi Wesley Masui",
      "orcid": "0000-0002-4279-6946"
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      "name": "Juan Mena-Parra",
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      "name": "Kyle Miller",
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      "name": "Nikola Milutinović",
      "orcid": "0000-0001-8292-0051"
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      "name": "Arash Mirhosseini",
      "orcid": "0000-0002-2626-5985"
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      "name": "Laura B. Newburgh",
      "orcid": "0000-0002-7333-5552"
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      "name": "Anna Ordog",
      "orcid": "0000-0002-2465-8937"
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        11
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      "name": "Ue‐Li Pen",
      "orcid": "0000-0003-2155-9578"
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      "name": "Tristan Pinsonneault-Marotte",
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      "name": "Alex Reda",
      "orcid": "0000-0001-6967-7253"
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      "name": "Andre Renard",
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      "name": "Kana Sakaguri",
      "orcid": "0000-0001-5667-8118"
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      "name": "J. Richard Shaw",
      "orcid": "0000-0002-4543-4588"
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      "name": "Shabbir Shaikh",
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      "name": "Seth R. Siegel",
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      "name": "Saurabh Singh",
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      "name": "David Spear",
      "orcid": "0009-0003-6054-8035"
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      "name": "Yukari Uchibori",
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      "name": "K. Vanderlinde",
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      "name": "Haochen Wang",
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      "name": "Donald V. Wiebe",
      "orcid": "0000-0002-6669-3159"
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    {
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      "name": "Dallas Wulf",
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  "bibtex": "https://research.draconitic.com/paper/a2x3yjyxyt4sf.bib",
  "cited_by": 27,
  "doi": "10.3847/1538-4357/ae9835",
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  "language": "en",
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  "published": "2026-09-28",
  "publisher": "IOP Publishing",
  "ris": "https://research.draconitic.com/paper/a2x3yjyxyt4sf.ris",
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      "origin": "journal-openalex:3103|Stellar, planetary, and galactic studies",
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  "title": "Detection of the Cosmological 21 cm Signal in Autocorrelation at z ∼ 1 with the Canadian Hydrogen Intensity Mapping Experiment",
  "title_text": "Detection of the Cosmological 21 cm Signal in Autocorrelation at z ∼ 1 with the Canadian Hydrogen Intensity Mapping Experiment",
  "type": "peer-reviewed",
  "updated_at": "2026-11-09T13:21:02Z",
  "url": "https://research.draconitic.com/paper/a2x3yjyxyt4sf",
  "venue": "The Astrophysical Journal",
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}