{
  "abstract": "The discovery of Little Red Dots (LRDs) at high redshifts with JWST has revealed a previously unknown phase of black-hole growth. However, their black-hole (BH) masses, BH-to-stellar mass ratios, cold-gas reservoirs, and depletion times remain uncertain. The recent discovery of low-redshift LRDs at $z\\simeq0.1 - 0.9$ creates a decisive opportunity to access their low-$J$ CO lines for measuring molecular gas reservoirs, and the nearest systems can in principle be spatially resolved. We use J1025+1402 (\"The Egg\") at $z=0.1007$, the best-studied local LRD, as a benchmark to explore the scientific opportunities with ALMA2040. Assuming a molecular gas mass of $10^9\\,M_\\odot$, the CO(2-1) detectability strongly depends on the assumed CO-to-H$_2$ conversion ($α_{\\rm CO}$). With a large $α_{\\rm CO} \\simeq 315 - 725\\,M_\\odot\\,({\\rm K\\,km\\,s}^{-1}\\,{\\rm pc}^2)^{-1}$ at a low gas-phase metallicity, the CO line would remain very challenging for the current ALMA to detect, while ALMA2040 will likely deliver a robust CO detection and thus a gas-reservoir constraint for The Egg. Furthermore, with the best angular resolution at its CO(2-1) frequency (14.6 mas, or 27 pc), ALMA2040 may spatially resolve the CO emission from The Egg. Assuming an optimistic, SMC-like $α_{\\rm CO}$ with a 50-hour deep integration, we produce mock position-velocity diagrams that may distinguish a $10^7\\,M_\\odot$ black hole from the no-BH model through its steeper central velocity structure. We conclude that ALMA2040 has the potential to directly measure the gas masses, depletion times, and excitation of local LRDs, while the CO-bright subset may ultimately yield dynamical constraints on the mass of their central black holes.",
  "abstract_shown": true,
  "affiliations": [],
  "article_type": null,
  "arxiv": "2610.20697",
  "author_total": 4,
  "authors": [
    {
      "name": "Fengwu Sun"
    },
    {
      "name": "Xiaojing Lin"
    },
    {
      "name": "Miguel Pereira-Santaella"
    },
    {
      "name": "Dieu D. Nguyen"
    }
  ],
  "bibtex": "https://research.draconitic.com/paper/ar0gebm3tjbqg.bib",
  "cited_by": 0,
  "doi": "10.48550/arxiv.2610.20697",
  "fulltext_url": null,
  "id": "ar0gebm3tjbqg",
  "issns": [],
  "landing_url": "https://arxiv.org/abs/2610.20697",
  "language": null,
  "licence": "CC-BY-4.0",
  "licence_label": "CC BY 4.0",
  "licence_source": "article",
  "licence_url": "http://creativecommons.org/licenses/by/4.0/",
  "metadata_licence": "CC0-1.0",
  "native_subjects": [
    [
      "arxiv",
      "astro-ph.GA"
    ],
    [
      "arxiv",
      "astro-ph.IM"
    ],
    [
      "openalex",
      "3103|Galaxies: Formation, Evolution, Phenomena"
    ]
  ],
  "openalex": "W7222678642",
  "pdf_url": "https://arxiv.org/pdf/2610.20697",
  "pmcid": null,
  "pmid": null,
  "published": "2026-10-14",
  "publisher": null,
  "ris": "https://research.draconitic.com/paper/ar0gebm3tjbqg.ris",
  "sources": [
    {
      "first_seen": "2026-10-30T12:29:50Z",
      "native_id": "2610.20697",
      "source": "arxiv",
      "url": "https://arxiv.org/abs/2610.20697"
    }
  ],
  "subjects": [
    {
      "field": "astronomy",
      "origin": "arxiv:astro-ph.GA",
      "subfield": "galaxies"
    },
    {
      "field": "astronomy",
      "origin": "arxiv:astro-ph.IM",
      "subfield": "instrumentation-methods"
    }
  ],
  "title": "A Vision for Little Red Dots in the Low-Redshift Universe with ALMA2040",
  "title_text": "A Vision for Little Red Dots in the Low-Redshift Universe with ALMA2040",
  "type": "preprint",
  "updated_at": "2026-10-30T12:29:50Z",
  "url": "https://research.draconitic.com/paper/ar0gebm3tjbqg",
  "venue": "arXiv",
  "versions": []
}