{
  "abstract": "We present a systematic search for broad H$β$ emission at $7<z<9.5$ in 21,770 JWST/NIRSpec PRISM spectra drawn from four blank fields and six lensing clusters with photometry spanning 1942 arcmin$^2$. We find a sample of 20 sources with statistically significant broad-H$β$ emission, including 13 new sources. Our entire sample has colors and morphologies consistent with little red dots (LRDs), compared to only 37\\% of broad-line emitters at $3.5<z<6$. Interpreting the broad-lines as indicators of Broad-line Active Galactic Nuclei (BLAGN), we infer black hole masses of $4.2\\times10^{6}-2.1\\times10^{8}$\\,$M_{\\odot}$. We calculate completeness corrections and construct the black hole mass function at $z\\sim8$. The normalization of the black hole mass function rises by $\\approx1.0$~dex from $z\\sim8-5$, consistent with average black hole growth at $f_{\\textrm{Edd}}\\approx0.1$. Comparing with cosmological simulations, the $z\\sim8$ black hole mass function requires heavy ($10^5$\\,$M_{\\odot}$) seeds or super-Eddington accretion onto light or intermediate mass seeds to match its normalization. Finally, we infer bolometric luminosities for the sample and construct a bolometric luminosity function. We integrate over this luminosity function to derive a black hole accretion density (BHAD) of $4.8^{+5.8}_{-2.6}\\times10^{-7}~M_{\\odot}~\\textrm{yr}^{-1}~\\textrm{Mpc}^{-3}$, showing broad agreement with previous photometric work, but disagreement with previous X-ray models, reinforcing the idea that BLAGN are more common in the early universe than previously expected.",
  "abstract_shown": true,
  "affiliations": [],
  "article_type": null,
  "arxiv": "2610.37564",
  "author_total": 32,
  "authors": [
    {
      "name": "Anthony J. Taylor"
    },
    {
      "name": "Steven L. Finkelstein"
    },
    {
      "name": "Hollis B. Akins"
    },
    {
      "name": "Vasily Kokorev"
    },
    {
      "name": "Pablo Arrabal Haro"
    },
    {
      "name": "Sophie Koudmani"
    },
    {
      "name": "Caitlin M. Casey"
    },
    {
      "name": "Mark Dickinson"
    },
    {
      "name": "Junehyoung Jeon"
    },
    {
      "name": "Madisyn Brooks"
    },
    {
      "name": "Volker Bromm"
    },
    {
      "name": "Christopher J. Conselice"
    },
    {
      "name": "Kelcey Davis"
    },
    {
      "name": "Callum T. Donnan"
    },
    {
      "name": "Andreas L. Faisst"
    },
    {
      "name": "Seiji Fujimoto"
    },
    {
      "name": "Lukas J. Furtak"
    },
    {
      "name": "Mauro Giavalisco"
    },
    {
      "name": "Ansh R. Gupta"
    },
    {
      "name": "Michaela Hirschmann"
    },
    {
      "name": "Tiger Yu-Yang Hsiao"
    },
    {
      "name": "Dale D. Kocevski"
    },
    {
      "name": "Anton M. Koekemoer"
    },
    {
      "name": "Gene C. K. Leung"
    },
    {
      "name": "Ray A. Lucas"
    },
    {
      "name": "Lorenzo Napolitano"
    },
    {
      "name": "Casey Papovich"
    },
    {
      "name": "Laura Pentericci"
    },
    {
      "name": "Pablo G. Perez-Gonzalez"
    },
    {
      "name": "Rachel S. Somerville"
    },
    {
      "name": "Fabian Walter"
    },
    {
      "name": "L. Y. Aaron Yung"
    }
  ],
  "bibtex": "https://research.draconitic.com/paper/avvvqc7tdcr5f.bib",
  "cited_by": 0,
  "doi": "10.48550/arxiv.2610.37564",
  "fulltext_url": null,
  "id": "avvvqc7tdcr5f",
  "issns": [],
  "landing_url": "https://arxiv.org/abs/2610.37564",
  "language": null,
  "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"
    ],
    [
      "openalex",
      "3103|Galaxies: Formation, Evolution, Phenomena"
    ]
  ],
  "openalex": "W7224135485",
  "pdf_url": "https://arxiv.org/pdf/2610.37564",
  "pmcid": null,
  "pmid": null,
  "published": "2026-10-27",
  "publisher": null,
  "ris": "https://research.draconitic.com/paper/avvvqc7tdcr5f.ris",
  "sources": [
    {
      "first_seen": "2026-10-30T12:35:50Z",
      "native_id": "2610.37564",
      "source": "arxiv",
      "url": "https://arxiv.org/abs/2610.37564"
    }
  ],
  "subjects": [
    {
      "field": "astronomy",
      "origin": "arxiv:astro-ph.GA",
      "subfield": "galaxies"
    }
  ],
  "title": "Little Red Dots with Broad H$β$ Lines Reveal the Black Hole Mass Function at 7<z<9.5",
  "title_text": "Little Red Dots with Broad Hβ Lines Reveal the Black Hole Mass Function at 7<z<9.5",
  "type": "preprint",
  "updated_at": "2026-10-30T12:35:50Z",
  "url": "https://research.draconitic.com/paper/avvvqc7tdcr5f",
  "venue": "arXiv",
  "versions": []
}