{
  "abstract": "Increased computing power and more efficient codes have allowed cosmological simulations of galaxy formation to grow massively in scale: the analysis of their outputs has consequently become a big data computational challenge. We present Octavius, a high-performance, hybrid-parallel simulation analysis toolkit. Octavius ingests a simulation snapshot with associated halo catalogue, locates galaxies with a 6D friends-of-friends algorithm, then produces an HDF5 catalogue of properties for haloes, subhaloes, and galaxies. The analysis is fast and memory efficient: we compare the performance against the widely used predecessor toolkit, Caesar, and show Octavius delivers order-of-magnitude improvements in speed with a factor of >5 reduction in peak memory. We demonstrate near-linear strong scaling of compute and linear peak memory scaling with the number of halo-assigned particles. Compute times scale with the superlinear computational load of larger haloes; we note the pipeline is presently I/O-limited. The code is written in Python and uses a declarative, plugin-based architecture so as to be easily extensible. Octavius can currently analyse SIMBA, SWIFT-KIARA, SWIFT-EAGLE, SWIFT-COLIBRE, and TNG snapshots; AHF, HBT-HERONS, and SUBFIND halo catalogues are supported. Properties computed include masses, galaxy photometry with dust attenuation, and kinematic, radial, morphological, and virial quantities. Output catalogues are easily accessed through a provided user API. The code is open sourced at https://github.com/jp-duminy/octavius",
  "abstract_shown": true,
  "affiliations": [],
  "article_type": null,
  "arxiv": "2611.08115",
  "author_total": 3,
  "authors": [
    {
      "name": "Jean-Paul Duminy"
    },
    {
      "name": "Jakub Szpila"
    },
    {
      "name": "Romeel Davé"
    }
  ],
  "bibtex": "https://research.draconitic.com/paper/amnb6a94cr5be.bib",
  "cited_by": 0,
  "doi": "10.48550/arxiv.2611.08115",
  "fulltext_url": null,
  "id": "amnb6a94cr5be",
  "issns": [],
  "landing_url": "https://arxiv.org/abs/2611.08115",
  "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": null,
  "pdf_url": "https://arxiv.org/pdf/2611.08115",
  "pmcid": null,
  "pmid": null,
  "published": "2026-11-05",
  "publisher": null,
  "ris": "https://research.draconitic.com/paper/amnb6a94cr5be.ris",
  "sources": [
    {
      "first_seen": "2026-11-06T18:21:30Z",
      "native_id": "2611.08115",
      "source": "arxiv",
      "url": "https://arxiv.org/abs/2611.08115"
    }
  ],
  "subjects": [
    {
      "field": "astronomy",
      "origin": "arxiv:astro-ph.GA",
      "subfield": "galaxies"
    },
    {
      "field": "astronomy",
      "origin": "arxiv:astro-ph.IM",
      "subfield": "instrumentation-methods"
    }
  ],
  "title": "Octavius: A High-Performance Analysis Toolkit for Galaxy Simulations",
  "title_text": "Octavius: A High-Performance Analysis Toolkit for Galaxy Simulations",
  "type": "preprint",
  "updated_at": "2026-11-09T00:20:41Z",
  "url": "https://research.draconitic.com/paper/amnb6a94cr5be",
  "venue": "arXiv",
  "versions": []
}