{
  "abstract": "We present the largest statistical spectroscopic sample of radio quasars at 4.7<z<6.7 to date. These have been selected from a dedicated Dark Energy Survey Instrument (DESI) target program and provide a robust sample to study the influence of radio jets on early quasar evolution. Using low-frequency radio data from the LOFAR Two Metre Sky Survey Data Release 3 (LoTSS-DR3) at 144 MHz, we identify 83 high-z radio quasars, 26 of which are classified as radio-loud (5-15% of 646 confirmed high-z quasars, defined as $R = F_{5\\text{GHz}}/F_{4400A} >10$). With radio luminosities of $\\sim10^{25-28}$ W/Hz, the radio emission in all 83 quasars is expected to be jet-dominated rather than powered by star formation. Analysis of their rest-frame ultra-violet (UV) spectra reveals broadly similar composite spectral properties and CIV velocity shifts compared to radio non-detected quasars. The radio-detected and radio-loud quasars exhibit slightly smaller Ly$α$ and CIV equivalent widths on average, however, we find no significant evidence ($\\sim1.3σ$) for a higher fraction of weak-line quasars (WLQs; ~10+/-4% versus ~4+/-1% for radio non-detected quasars). We further find that the broad absorption line (BAL) quasars are predominantly radio-quiet, and no correlation is observed between absorption index and radio-loudness, suggesting that radio emission is not produced by the BAL outflows themselves and are physically distinct phenomena. Our results demonstrate that powerful radio jets were already well-established by z~5.",
  "abstract_shown": true,
  "affiliations": [],
  "article_type": null,
  "arxiv": "2609.26931",
  "author_total": 58,
  "authors": [
    {
      "name": "Anniek J Gloudemans"
    },
    {
      "name": "Jinyi Yang"
    },
    {
      "name": "David M Alexander"
    },
    {
      "name": "Arjun Dey"
    },
    {
      "name": "Xiaohui Fan"
    },
    {
      "name": "Victoria A Fawcett"
    },
    {
      "name": "Martin J Hardcastle"
    },
    {
      "name": "Stephanie Juneau"
    },
    {
      "name": "George K Miley"
    },
    {
      "name": "Leah K Morabito"
    },
    {
      "name": "Adam D Myers"
    },
    {
      "name": "Swayamtrupta Panda"
    },
    {
      "name": "Huub J.A Röttgering"
    },
    {
      "name": "Timothy Shimwell"
    },
    {
      "name": "Daniel J.B Smith"
    },
    {
      "name": "Feige Wang"
    },
    {
      "name": "J Aguilar"
    },
    {
      "name": "S Ahlen"
    },
    {
      "name": "D Bianchi"
    },
    {
      "name": "D Brooks"
    },
    {
      "name": "T Claybaugh"
    },
    {
      "name": "A Cuceu"
    },
    {
      "name": "A de la Macorra"
    },
    {
      "name": "P Doel"
    },
    {
      "name": "S Ferraro"
    },
    {
      "name": "J.E Forero-Romero"
    },
    {
      "name": "E Gaztañaga"
    },
    {
      "name": "S Gontcho A. Gontcho"
    },
    {
      "name": "G Gutierrez"
    },
    {
      "name": "C Hahn"
    },
    {
      "name": "M Ishak"
    },
    {
      "name": "R Joyce"
    },
    {
      "name": "R Kehoe"
    },
    {
      "name": "D Kirkby"
    },
    {
      "name": "T Kisner"
    },
    {
      "name": "A Kremin"
    },
    {
      "name": "M Landriau"
    },
    {
      "name": "L Le Guillou"
    },
    {
      "name": "M.E Levi"
    },
    {
      "name": "M Manera"
    },
    {
      "name": "A Meisner"
    },
    {
      "name": "R Miquel"
    },
    {
      "name": "J Moustakas"
    },
    {
      "name": "S Nadathur"
    },
    {
      "name": "W.J Percival"
    },
    {
      "name": "F Prada"
    },
    {
      "name": "I Pérez-Ràfols"
    },
    {
      "name": "A Robertson"
    },
    {
      "name": "G Rossi"
    },
    {
      "name": "E Sanchez"
    },
    {
      "name": "E.F Schlafly"
    },
    {
      "name": "D Schlegel"
    },
    {
      "name": "J Silber"
    },
    {
      "name": "D Sprayberry"
    },
    {
      "name": "G Tarlé"
    },
    {
      "name": "B.A Weaver"
    },
    {
      "name": "R Zhou"
    },
    {
      "name": "H Zou"
    }
  ],
  "bibtex": "https://research.draconitic.com/paper/ae5nk33rsz197.bib",
  "cited_by": 0,
  "doi": "10.48550/arxiv.2609.26931",
  "fulltext_url": null,
  "id": "ae5nk33rsz197",
  "issns": [],
  "landing_url": "https://hal.science/hal-05841977v1",
  "language": "en",
  "licence": "LicenseRef-arXiv-nonexclusive-1.0",
  "licence_label": "arXiv licence",
  "licence_source": "article",
  "licence_url": "http://arxiv.org/licenses/nonexclusive-distrib/1.0/",
  "metadata_licence": "CC0-1.0",
  "native_subjects": [
    [
      "arxiv",
      "astro-ph.GA"
    ],
    [
      "hal",
      "0.phys"
    ],
    [
      "hal",
      "1.phys.astr"
    ],
    [
      "openalex",
      "3103|Galaxies: Formation, Evolution, Phenomena"
    ]
  ],
  "openalex": "W7214221681",
  "pdf_url": "https://arxiv.org/pdf/2609.26931",
  "pmcid": null,
  "pmid": null,
  "published": "2026-09-22",
  "publisher": null,
  "ris": "https://research.draconitic.com/paper/ae5nk33rsz197.ris",
  "sources": [
    {
      "first_seen": "2026-10-30T12:18:02Z",
      "native_id": "hal-05841977",
      "source": "hal",
      "url": "https://hal.science/hal-05841977v1"
    },
    {
      "first_seen": "2026-10-30T12:23:56Z",
      "native_id": "2609.26931",
      "source": "arxiv",
      "url": "https://arxiv.org/abs/2609.26931"
    }
  ],
  "subjects": [
    {
      "field": "astronomy",
      "origin": "arxiv:astro-ph.GA",
      "subfield": "galaxies"
    },
    {
      "field": "physics",
      "origin": "hal:0.phys",
      "subfield": "general"
    }
  ],
  "title": "Radio Quasars in the Cosmic Dawn: A Spectroscopic Sample from the DESI Survey",
  "title_text": "Radio Quasars in the Cosmic Dawn: A Spectroscopic Sample from the DESI Survey",
  "type": "preprint",
  "updated_at": "2026-10-30T12:23:56Z",
  "url": "https://research.draconitic.com/paper/ae5nk33rsz197",
  "venue": "HAL",
  "versions": []
}