{
  "abstract": "We present the results of a search for continuous gravitational waves from the low-mass X-ray binary Scorpius X-1 using LIGO data from the first part of the fourth LIGO-Virgo-KAGRA observing run. By applying the resampling version of the cross-correlation pipeline to search for signal frequencies $f_0$ between $25$ and $200\\un{Hz}$ (corresponding to neutron star spin frequencies of $12.5$ to $100\\un{Hz}$ for GW due to triaxiality, or $\\sim15-20$ to $\\sim120-150\\un{Hz}$ for GW due to $r$-modes), we set upper limits below the standard torque balance level, independent of neutron star spin inclination, for $50\\un{Hz}\\lesssim f_0\\lesssim200\\un{Hz}$. While uncertainties in the modelling of torque and equation of state limit the strength of our inference, our results nonetheless argue against torque balance in this spin range for a neutron star described by a hadronic equation of state. The most sensitive upper limits on the gravitational wave amplitude $h_0$, at the upper end of the frequency band searched, approach $5\\times10^{-26}$ marginalized over inclination angle and $2\\times10^{-26}$ assuming the most favorable inclination. The marginalized upper limits correspond to a sensitivity depth of $70-75\\un{Hz}^{-1/2}$, improving sensitivity considerably over previous searches. Expressed as constraints on the triaxial deformation of the neutron star, the limits correspond to an ellipticity of $3\\times10^{-5}$ if the GW frequency $f_0$ is $75\\un{Hz}$ and $3\\times10^{-6}$ if $f_0=200\\un{Hz}$, approaching deformations which could be supported by ordinary nuclear matter. Outliers from the search were ruled out as potential signals by a combination of hierarchical followup and analysis of additional data from later in the observing run.",
  "abstract_shown": true,
  "affiliations": [
    "Max Planck Institute for Gravitational Physics (Albert Einstein Institute)",
    "LIGO Hanford Observatory",
    "Università di Salerno",
    "INFN",
    "University of Warwick",
    "University of Western Australia",
    "Monash University",
    "The Pennsylvania State University",
    "Leibniz Universität Hannover",
    "University of Wisconsin-Milwaukee",
    "California Institute of Technology",
    "Louisiana State University",
    "Tata Institute of Fundamental Research",
    "Centre de Physique Théorique",
    "Université catholique de Louvain",
    "Queen Mary University of London",
    "University of California",
    "University of Minnesota",
    "Instituto Nacional de Pesquisas Espaciais",
    "Université Paris Cité",
    "Università di Roma Tor Vergata",
    "Universiteit Antwerpen",
    "Gravitational Wave Science Project",
    "Advanced Technology Center",
    "Friedrich-Schiller-Universität Jena",
    "INFN Sezione di Torino",
    "Universität Hamburg",
    "Università degli Studi di Genova",
    "Univ. Savoie Mont Blanc",
    "Università di Napoli “Federico II,” I-80126 Napoli,",
    "Cardiff University",
    "Australian National University",
    "Massachusetts Institute of Technology",
    "Maastricht University",
    "Nikhef",
    "Università di Roma “La Sapienza,”",
    "Aix Marseille Univ",
    "Université Paris-Saclay",
    "The University of Tokyo",
    "Gran Sasso Science Institute (GSSI)"
  ],
  "article_type": null,
  "arxiv": "2607.07765",
  "author_total": 1838,
  "authors": [
    {
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        0
      ],
      "name": "A. G. Abac",
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      "affs": [
        1
      ],
      "name": "I. Abouelfettouh"
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    {
      "affs": [
        2,
        3
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      "name": "F. Acernese"
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    {
      "affs": [
        4
      ],
      "name": "K. Ackley",
      "orcid": "0000-0002-8648-0767"
    },
    {
      "affs": [
        5
      ],
      "name": "A. Adam"
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    {
      "affs": [
        6
      ],
      "name": "C. Adamcewicz",
      "orcid": "0000-0001-5525-6255"
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    {
      "affs": [
        7
      ],
      "name": "S. Adhicary",
      "orcid": "0009-0004-2101-5428"
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        0,
        8
      ],
      "name": "D. Adhikari"
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    {
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        9
      ],
      "name": "N. Adhikari",
      "orcid": "0000-0002-4559-8427"
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        10
      ],
      "name": "R. X. Adhikari",
      "orcid": "0000-0002-5731-5076"
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    {
      "affs": [
        11
      ],
      "name": "V. K. Adkins"
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    {
      "affs": [
        12
      ],
      "name": "S. Afroz",
      "orcid": "0009-0004-4459-2981"
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      "name": "A. Agapito",
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      "name": "I.-L. Ahrend"
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      "name": "L. Aiello",
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      "name": "A. Ain",
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      "name": "P. Ajith",
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      "name": "T. Akutsu",
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      "name": "S. Albanesi",
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      "name": "L. Albers"
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        27
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      "name": "W. Ali"
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        0,
        8
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      "name": "S. Al-Kershi"
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      "name": "C. Alléné"
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      "name": "A. Allocca",
      "orcid": "0000-0002-5288-1351"
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      "affs": [
        30
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      "name": "S. Al-Shammari"
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        31
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      "name": "P. A. Altin",
      "orcid": "0000-0001-8193-5825"
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      "affs": [
        32
      ],
      "name": "S. Alvarez-Lopez",
      "orcid": "0009-0003-8040-4936"
    },
    {
      "affs": [
        28
      ],
      "name": "W. Amar"
    },
    {
      "affs": [
        30
      ],
      "name": "O. Amarasinghe"
    },
    {
      "affs": [
        33,
        34
      ],
      "name": "A. Amato",
      "orcid": "0000-0001-9557-651X"
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    {
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        3,
        35
      ],
      "name": "F. Amicucci",
      "orcid": "0009-0005-2139-4197"
    },
    {
      "affs": [
        36
      ],
      "name": "C. Amra"
    },
    {
      "affs": [
        6
      ],
      "name": "C. Anand"
    },
    {
      "affs": [
        10
      ],
      "name": "A. Ananyeva"
    },
    {
      "affs": [
        10
      ],
      "name": "S. B. Anderson",
      "orcid": "0000-0003-2219-9383"
    },
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      "affs": [
        10
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      "name": "W. G. Anderson",
      "orcid": "0000-0003-0482-5942"
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    {
      "affs": [
        37
      ],
      "name": "M. Andia",
      "orcid": "0000-0003-3675-9126"
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    {
      "affs": [
        38
      ],
      "name": "M. Ando",
      "orcid": "0000-0002-8865-9998"
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        32
      ],
      "name": "M. Andrés-Carcasona",
      "orcid": "0000-0002-8738-1672"
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    {
      "affs": [
        16
      ],
      "name": "J. L. Andrey"
    },
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        39,
        3
      ],
      "name": "T. Andrić",
      "orcid": "0000-0002-9277-9773"
    },
    {
      "name": "J. Anglin"
    },
    {
      "name": "J. Anna"
    },
    {
      "affs": [
        3
      ],
      "name": "S. Ansoldi",
      "orcid": "0000-0002-5613-7693"
    },
    {
      "name": "J. M. Antelis",
      "orcid": "0000-0003-3377-0813"
    },
    {
      "affs": [
        37
      ],
      "name": "S. Antier",
      "orcid": "0000-0002-7686-3334"
    },
    {
      "affs": [
        38
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      "name": "M. Aoumi"
    },
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      "affs": [
        3
      ],
      "name": "E. Z. Appavuravther"
    },
    {
      "affs": [
        10
      ],
      "name": "S. Appert"
    },
    {
      "name": "S. K. Apple",
      "orcid": "0009-0007-4490-5804"
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    {
      "affs": [
        10
      ],
      "name": "K. Arai",
      "orcid": "0000-0001-8916-8915"
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    {
      "affs": [
        38
      ],
      "name": "A. Araya",
      "orcid": "0000-0002-6884-2875"
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    {
      "affs": [
        10
      ],
      "name": "M. C. Araya",
      "orcid": "0000-0002-6018-6447"
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    {
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        39,
        3
      ],
      "name": "M. Arca Sedda",
      "orcid": "0000-0002-3987-0519"
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        20,
        3
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      "name": "F. Arciprete",
      "orcid": "0000-0003-3602-3717"
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  "bibtex": "https://research.draconitic.com/paper/2m9qbekdfjxsj.bib",
  "cited_by": 0,
  "doi": "10.3847/2041-8213/aea296",
  "fulltext_url": null,
  "id": "2m9qbekdfjxsj",
  "issns": [
    "2041-8205",
    "2041-8213"
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  "landing_url": "https://hal.science/hal-05743968v1",
  "language": "en",
  "licence": "CC-BY-4.0",
  "licence_label": "CC BY 4.0",
  "licence_source": "article",
  "licence_url": "https://creativecommons.org/licenses/by/4.0/",
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      "openalex",
      "3103|Pulsars and Gravitational Waves Research"
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  "pdf_url": "https://iopscience.iop.org/article/10.3847/2041-8213/aea296/pdf",
  "pmcid": null,
  "pmid": null,
  "published": "2026-09-09",
  "publisher": "American Astronomical Society",
  "ris": "https://research.draconitic.com/paper/2m9qbekdfjxsj.ris",
  "sources": [
    {
      "first_seen": "2026-10-30T12:17:31Z",
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      "url": "https://hal.science/hal-05743968v1"
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    {
      "field": "physics",
      "origin": "hal:1.phys.grqc",
      "subfield": "gravitation"
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  ],
  "title": "Sub-Torque-Balance Upper Limits on Continuous Gravitational Waves from Scorpius X-1",
  "title_text": "Sub-Torque-Balance Upper Limits on Continuous Gravitational Waves from Scorpius X-1",
  "type": "peer-reviewed",
  "updated_at": "2026-11-05T12:20:12Z",
  "url": "https://research.draconitic.com/paper/2m9qbekdfjxsj",
  "venue": "Astrophys.J.Lett.",
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}