{
  "abstract": "Detailed UV-to-optical studies of galaxies at z >= 10 have largely focused on bright systems (MUV <= -20 mag), leaving intrinsically faint galaxies virtually unexplored to date. Combining NIRCam, NIRSpec, and MIRI imaging and spectroscopy, we investigate UNCOVER-ABELL2744-13151 (U13151), an ultra-faint galaxy at z = 9.7995 (MUV = -17.44 mag), magnified by Abell 2744 ($μ$ = 12.8). U13151 is very blue ($β$ ~ -2.64), ultra-low mass (log10(M*/Msun) ~ 6.68), young (~ 5.5 Myr), metal-poor (Z ~ 3-6% Zsun), and compact (Re ~ 122 pc). It exhibits negligible dust attenuation, extreme ionization conditions, and intense star formation (sSFR(Ha) ~ 94 Gyr-1, or equivalently M*/SFR(Ha) ~ 10.6 Myr). Despite similarities with much brighter galaxies, its low C/O, approximately solar Ne/O, and undetected nitrogen emission suggest enrichment dominated by core-collapse supernovae, in stark contrast with similar nitrogen-enhanced systems. U13151 might be undergoing its first major episode of star formation, assembling most (if not all) of its M* through five unresolved clumps. Its high ionizing photon production efficiency (log10($ξ_{\\rm ion}$/ (Hz erg-1)) ~ 25.64) suggests, through a simple toy model, suggests, through a simple toy model, that similarly short-lived episodes could contribute significantly to the ionizing photon budget of low-mass galaxies during Cosmic Reionization. We explore different evolutionary scenarios, from U13151-like galaxies potentially representing the progenitors of Blue Monsters at higher redshifts to the possibility that such systems could be the early building blocks of present-day Milky Way-like galaxies. Our results highlight the fundamental role of MIRI in studying galaxies in the early Universe and the urgent need to investigate the faintest, lowest-mass systems to shed light on the fundamental physics driving the earliest phases of galaxy formation.",
  "abstract_shown": true,
  "affiliations": [],
  "article_type": null,
  "arxiv": "2610.26560",
  "author_total": 38,
  "authors": [
    {
      "name": "Pierluigi Rinaldi"
    },
    {
      "name": "Javier Álvarez-Márquez"
    },
    {
      "name": "Alejandro Crespo Gómez"
    },
    {
      "name": "Luis Colina"
    },
    {
      "name": "Stefano Carniani"
    },
    {
      "name": "Sarah Kendrew"
    },
    {
      "name": "Edoardo Iani"
    },
    {
      "name": "Angela Adamo"
    },
    {
      "name": "Abdurro'uf"
    },
    {
      "name": "Marianna Annunziatella"
    },
    {
      "name": "Stacey Alberts"
    },
    {
      "name": "Leindert A. Boogaard"
    },
    {
      "name": "Karina I. Caputi"
    },
    {
      "name": "Marco Castellano"
    },
    {
      "name": "Michele Catone"
    },
    {
      "name": "Rui Marques-Chaves"
    },
    {
      "name": "Ryan Cooper"
    },
    {
      "name": "Seiji Fujimoto"
    },
    {
      "name": "Mahmoud Hamed"
    },
    {
      "name": "Yuichi Harikane"
    },
    {
      "name": "Santosh Harish"
    },
    {
      "name": "Takuya Hashimoto"
    },
    {
      "name": "Jakob M. Helton"
    },
    {
      "name": "Tiger Y. -Y. Hsiao"
    },
    {
      "name": "Vasily Kokorev"
    },
    {
      "name": "Álvaro Labiano"
    },
    {
      "name": "Jens Melinder"
    },
    {
      "name": "Ikki Mitsuhashi"
    },
    {
      "name": "Göran Östlin"
    },
    {
      "name": "Lorenzo Napolitano"
    },
    {
      "name": "Borja Pérez-Díaz"
    },
    {
      "name": "Pablo G. Pérez-González"
    },
    {
      "name": "Carlota Prieto Jiménez"
    },
    {
      "name": "Giulia Rodighiero"
    },
    {
      "name": "Paola Santini"
    },
    {
      "name": "Ana Varo-O'Ferrall"
    },
    {
      "name": "Jorge A. Zavala"
    },
    {
      "name": "Yongda Zhu"
    }
  ],
  "bibtex": "https://research.draconitic.com/paper/4entpkch3jrtt.bib",
  "cited_by": 0,
  "doi": "10.48550/arxiv.2610.26560",
  "fulltext_url": null,
  "id": "4entpkch3jrtt",
  "issns": [],
  "landing_url": "https://arxiv.org/abs/2610.26560",
  "language": null,
  "licence": "CC0-1.0",
  "licence_label": "CC0",
  "licence_source": "article",
  "licence_url": "http://creativecommons.org/publicdomain/zero/1.0/",
  "metadata_licence": "CC0-1.0",
  "native_subjects": [
    [
      "arxiv",
      "astro-ph.GA"
    ],
    [
      "openalex",
      "3103|Galaxies: Formation, Evolution, Phenomena"
    ]
  ],
  "openalex": "W7223061713",
  "pdf_url": "https://arxiv.org/pdf/2610.26560",
  "pmcid": null,
  "pmid": null,
  "published": "2026-10-19",
  "publisher": null,
  "ris": "https://research.draconitic.com/paper/4entpkch3jrtt.ris",
  "sources": [
    {
      "first_seen": "2026-10-30T12:30:52Z",
      "native_id": "2610.26560",
      "source": "arxiv",
      "url": "https://arxiv.org/abs/2610.26560"
    }
  ],
  "subjects": [
    {
      "field": "astronomy",
      "origin": "arxiv:astro-ph.GA",
      "subfield": "galaxies"
    }
  ],
  "title": "PRISMS/U13151. A Glimpse into the Earliest Phases of Galaxy Formation through an Ultra-Faint System $\\approx$ 500 Myr after the Big Bang",
  "title_text": "PRISMS/U13151. A Glimpse into the Earliest Phases of Galaxy Formation through an Ultra-Faint System ≈ 500 Myr after the Big Bang",
  "type": "preprint",
  "updated_at": "2026-10-30T12:33:41Z",
  "url": "https://research.draconitic.com/paper/4entpkch3jrtt",
  "venue": "arXiv",
  "versions": []
}