{
  "abstract": "We present a Bayesian hierarchical forward model for mapping the local luminosity-density field from heterogeneous redshift surveys. By dividing the survey volume into angular cells and redshift shells, we model the observed galaxy distribution directly in apparent-magnitude and redshift space. This allows us to infer cell-level luminosity functions and densities while preserving each survey’s unique selection function. Simultaneously, the ensemble of cells constrains the cosmic-mean luminosity function, its redshift evolution, and the hyperparameters describing cell-to-cell variation. We apply the framework to the Two Micron All-Sky Redshift Survey, 6dF Galaxy Survey, and Galaxy And Mass Assembly survey over $0.005\\lt z\\lt 0.065$, combining wide sky coverage with deeper and fainter galaxy samples. The model successfully recovers global J-band luminosity-function parameters and a mean luminosity density consistent with previous low-redshift measurements. The inferred luminosity-density scatter decreases with volume, consistent with the cosmic-variance amplitude expected in a Lambda cold dark matter Universe. Within the volume we probe, we find no evidence for a large coherent underdensity. Instead, the local Universe is broadly consistent with smooth evolution and cosmic variance. The nearest shell at $z \\simeq 0.01$ is the clearest exception, lying ${\\simeq} 0.12$ dex (${\\simeq} 25 {{\\ \\rm per\\ cent}}$) below the smooth global model, a $-2.6\\sigma$ underdensity with a one-sided significance of ${\\simeq} 99.5 {{\\ \\rm per\\ cent}}$. This framework offers a scalable architecture for mapping cosmic density fields with next-generation wide and deep surveys.",
  "abstract_shown": true,
  "affiliations": [
    "Centre for Astrophysics and Supercomputing, Swinburne University of Technology , Hawthorn, VIC 3122 ,",
    "Research School of Astronomy and Astrophysics, Australian National University , Canberra, ACT 2611 ,"
  ],
  "article_type": null,
  "arxiv": null,
  "author_total": 4,
  "authors": [
    {
      "affs": [
        0
      ],
      "name": "Aryan Bansal",
      "orcid": "0000-0002-6631-1886"
    },
    {
      "affs": [
        0
      ],
      "name": "Edward N Taylor",
      "orcid": "0000-0002-5522-9107"
    },
    {
      "affs": [
        0
      ],
      "name": "Michelle Cluver",
      "orcid": "0000-0002-9871-6490"
    },
    {
      "affs": [
        1
      ],
      "name": "Matthew Colless",
      "orcid": "0000-0001-9552-8075"
    }
  ],
  "bibtex": "https://research.draconitic.com/paper/0y5eq3f6kxk0e.bib",
  "cited_by": 0,
  "doi": "10.1093/mnras/stag1867",
  "fulltext_url": null,
  "id": "0y5eq3f6kxk0e",
  "issns": [
    "0035-8711",
    "1365-2966"
  ],
  "landing_url": "https://academic.oup.com/mnras/article/doi/10.1093/mnras/stag1867/8865304",
  "language": null,
  "licence": "CC-BY-4.0",
  "licence_label": "CC BY 4.0",
  "licence_source": "article",
  "licence_url": "https://creativecommons.org/licenses/by/4.0/",
  "metadata_licence": null,
  "native_subjects": [
    [
      "openalex",
      "3103|Galaxies: Formation, Evolution, Phenomena"
    ]
  ],
  "openalex": "W7214903306",
  "pdf_url": "https://academic.oup.com/mnras/advance-article-pdf/doi/10.1093/mnras/stag1867/71606367/stag1867.pdf",
  "pmcid": null,
  "pmid": null,
  "published": "2026-10-05",
  "publisher": "Oxford University Press (OUP)",
  "ris": "https://research.draconitic.com/paper/0y5eq3f6kxk0e.ris",
  "sources": [
    {
      "first_seen": "2026-10-30T12:18:17Z",
      "native_id": "10.1093/mnras/stag1867",
      "source": "crossref",
      "url": "https://academic.oup.com/mnras/article/doi/10.1093/mnras/stag1867/8865304"
    }
  ],
  "subjects": [
    {
      "field": "astronomy",
      "origin": "openalex:3103|Galaxies: Formation, Evolution, Phenomena",
      "subfield": "galaxies"
    }
  ],
  "title": "Everything everywhere all at once: a hierarchical framework for mapping anisotropies in the local Universe",
  "title_text": "Everything everywhere all at once: a hierarchical framework for mapping anisotropies in the local Universe",
  "type": "peer-reviewed",
  "updated_at": "2026-10-30T12:18:17Z",
  "url": "https://research.draconitic.com/paper/0y5eq3f6kxk0e",
  "venue": "Monthly Notices of the Royal Astronomical Society",
  "versions": [
    {
      "doi": "10.48550/arxiv.2609.36462",
      "pid": "dwra00m9jkpdj",
      "relation": "preprint",
      "title": "Everything Everywhere All At Once: A Hierarchical Framework for Mapping Anisotropies in the Local Universe",
      "venue": "arXiv"
    }
  ]
}