{
  "abstract": "We present results from a comprehensive multiwavelength monitoring campaign of the changing-look active galactic nucleus 1ES 1927+654 during the onset and evolution of a relativistic radio jet ∼(2022 May–2025 August), using observations from XMM-Newton, Swift, Telescopio Nazionale Galileo (TNG), the Zwicky Transient Facility (ZTF), Very Large Array (VLA), and Very Long Baseline Array (VLBA). The soft X-ray emission lines at ∼0.56 keV and ∼1 keV have appeared with variable strength and width during the formation of the nascent jet. We note that the ∼1 keV feature has been persisting since the post-2017 flare phase. We also report the detection of a broad (∼800 eV) FeK emission feature at (6–7) keV in the ∼70 ks stacked EPIC-pn spectra, marking the first such detection, which historically was lacking in this source. The joint spectral fitting of XMM-Newton EPIC-pn and Reflection Grating Spectrometer (RGS) data reveals the presence of ionized absorbers in 2022 ( log ξ / erg cm s − 1 ∼ 1.5 ± 0.3 , N H ∼ 2.5 ± 0.9 × 10 ²⁰ cm ⁻² ), but weaker than that detected during the high accretion state in 2018 (Eddington ratio, λ Edd > 1). The absorption features further weakened in 2023–2025 and were marginally detectable ( N H ≤ 10 ²⁰ cm ⁻² ). The entire scenario is suggestive of a real-time transition of the accretion flow (from λ Edd > 1 to λ Edd ∼ 0.3) during which the winds become weaker and the jet starts to form and evolve. Furthermore, both the soft X-ray (0.3–2) keV and 5 GHz radio fluxes, which increased by factors of ∼10 and ∼60, respectively, since 2022, have recently plateaued at elevated levels, indicating a stabilized accretion disk, corona, and jet configuration.",
  "abstract_shown": true,
  "affiliations": [
    "Astrophysics Science Division",
    "University of Maryland Baltimore County",
    "Center for Research and Exploration in Space Science and Technology",
    "University of Delhi",
    "MKHS",
    "European Space Agency (ESA)",
    "Center for Astrophysics ∣ Harvard & Smithsonian",
    "Harvard University",
    "Università degli Studi Roma Tre",
    "Saint Mary’s University",
    "Princeton University",
    "University of Maryland",
    "MIT Kavli Institute for Astrophysics and Space Research",
    "University of Michigan",
    "Space Telescope Science Institute",
    "Instituto de Estudios Astrofísicos",
    "Peking University",
    "University of Colorado and National Institute of Standards and Technology",
    "Aryabhatta Research Institute of Observational Sciences (ARIES)",
    "INAF—Istituto di Astrofisica e Planetologia Spaziali",
    "Department of Physics",
    "INAF—Osservatorio Astronomico di Roma",
    "The Catholic University of America",
    "INAF"
  ],
  "article_type": null,
  "arxiv": null,
  "author_total": 30,
  "authors": [
    {
      "affs": [
        0,
        1,
        2
      ],
      "name": "Dev R. Sadaula",
      "orcid": "0000-0002-9163-8653"
    },
    {
      "affs": [
        0,
        1,
        2
      ],
      "name": "Sibasish Laha",
      "orcid": "0000-0003-2714-0487"
    },
    {
      "affs": [
        1
      ],
      "name": "Eileen T. Meyer",
      "orcid": "0000-0002-7676-9962"
    },
    {
      "affs": [
        1
      ],
      "name": "Onic I. Shuvo",
      "orcid": "0000-0003-4727-2209"
    },
    {
      "affs": [
        3
      ],
      "name": "Main Pal",
      "orcid": "0000-0001-6523-6522"
    },
    {
      "affs": [
        4
      ],
      "name": "Ritesh Ghosh",
      "orcid": "0000-0003-4790-2653"
    },
    {
      "affs": [
        5
      ],
      "name": "Matteo Guainazzi",
      "orcid": "0000-0002-1094-3147"
    },
    {
      "affs": [
        6,
        7
      ],
      "name": "Fabio Pacucci",
      "orcid": "0000-0001-9879-7780"
    },
    {
      "affs": [
        8
      ],
      "name": "Stefano Bianchi",
      "orcid": "0000-0002-4622-4240"
    },
    {
      "affs": [
        9
      ],
      "name": "Luigi Gallo",
      "orcid": "0009-0006-4968-7108"
    },
    {
      "affs": [
        10
      ],
      "name": "Rostom Mbarek",
      "orcid": "0000-0001-9475-5292"
    },
    {
      "affs": [
        11
      ],
      "name": "Amelia M. Hankla",
      "orcid": "0000-0001-9725-5509"
    },
    {
      "affs": [
        8
      ],
      "name": "Fabio La Franca",
      "orcid": "0000-0002-1239-2721"
    },
    {
      "affs": [
        1
      ],
      "name": "Tahir Yaqoob",
      "orcid": "0009-0002-6505-5742"
    },
    {
      "affs": [
        12
      ],
      "name": "Megan Masterson",
      "orcid": "0000-0003-4127-0739"
    },
    {
      "affs": [
        12
      ],
      "name": "Erin Kara",
      "orcid": "0000-0003-0172-0854"
    },
    {
      "affs": [
        13,
        14
      ],
      "name": "Missagh Mehdipour",
      "orcid": "0000-0002-4992-4664"
    },
    {
      "affs": [
        15,
        16
      ],
      "name": "Claudio Ricci",
      "orcid": "0000-0001-5231-2645"
    },
    {
      "affs": [
        0
      ],
      "name": "Javier A Garcia",
      "orcid": "0000-0003-3828-2448"
    },
    {
      "affs": [
        0
      ],
      "name": "Timothy R. Kallman",
      "orcid": "0000-0002-5779-6906"
    },
    {
      "affs": [
        0,
        11
      ],
      "name": "Ralf Ballhausen",
      "orcid": "0000-0002-1118-8470"
    },
    {
      "affs": [
        17
      ],
      "name": "Mitchell C. Begelman",
      "orcid": "0000-0003-0936-8488"
    },
    {
      "affs": [
        11
      ],
      "name": "Alexander Philippov",
      "orcid": "0000-0001-7801-0362"
    },
    {
      "affs": [
        18
      ],
      "name": "Suvendu Rakshit",
      "orcid": "0000-0002-8377-9667"
    },
    {
      "affs": [
        19
      ],
      "name": "Francesca Panessa",
      "orcid": "0000-0003-0543-3617"
    },
    {
      "affs": [
        20
      ],
      "name": "Ehud Behar",
      "orcid": "0000-0001-9735-4873"
    },
    {
      "affs": [
        0,
        11
      ],
      "name": "S. Bradley Cenko",
      "orcid": "0000-0003-1673-970X"
    },
    {
      "affs": [
        8,
        21
      ],
      "name": "Federica Ricci",
      "orcid": "0000-0001-5742-5980"
    },
    {
      "affs": [
        8,
        21
      ],
      "name": "Ilaria Villani",
      "orcid": "0009-0006-7483-0463"
    },
    {
      "affs": [
        22,
        23
      ],
      "name": "James N. Reeves",
      "orcid": "0000-0003-3221-6765"
    }
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  "bibtex": "https://research.draconitic.com/paper/exgx62pv8vzg2.bib",
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  "doi": "10.3847/1538-4357/ae96b4",
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  "id": "exgx62pv8vzg2",
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    "1538-4357",
    "0004-637X"
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  "licence_label": "CC BY 4.0",
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  "pdf_url": "https://iopscience.iop.org/article/10.3847/1538-4357/ae96b4/pdf",
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  "published": "2026-10-29",
  "publisher": "American Astronomical Society",
  "ris": "https://research.draconitic.com/paper/exgx62pv8vzg2.ris",
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  "subjects": [
    {
      "field": "astronomy",
      "origin": "journal-openalex:3103|Stellar, planetary, and galactic studies",
      "subfield": "stellar"
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  ],
  "title": "The Emergence of X-Ray Emission Lines during Relativistic Radio-jet Formation in the Changing-look Active Galactic Nucleus 1ES 1927+654",
  "title_text": "The Emergence of X-Ray Emission Lines during Relativistic Radio-jet Formation in the Changing-look Active Galactic Nucleus 1ES 1927+654",
  "type": "peer-reviewed",
  "updated_at": "2026-10-31T00:20:43Z",
  "url": "https://research.draconitic.com/paper/exgx62pv8vzg2",
  "venue": "The Astrophysical Journal",
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}