{
  "abstract": "We present a fast algorithm to numerically evolve a spherically symmetric system consisting of dark matter and gas, including dark-matter-baryon scattering. The method augments the spherical N-body code NSphere, which collapses the six-dimensional phase space of a spherical collisionless system to three dimensions, with a one-dimensional Lagrangian treatment of gas. Dark-matter-baryon scattering is implemented as a Monte-Carlo process between the dark-matter numerical particles and the gas shells. We also implement an algorithm for radiative gas cooling that is valid for weak cooling. The gas, as well as dark-matter-baryon scattering and cooling, adds only incrementally to the run time of the code, allowing systems to be evolved on a laptop computer, a tiny fraction of the computational resources required for a full 3D N-body/hydro simulation. To illustrate, we show the evolution of a $\\sim 10^{13}\\,M_\\odot$ halo with a dark-matter-baryon scattering cross section $σ_{\\rm tot}/m_χ=0.1\\,{\\rm cm}^2\\,{\\rm g}^{-1}$ but no gas cooling. We then show examples with radiative gas cooling where the cooling is altered through interaction with dark-matter particles. The resulting code, NSphere-IDM, allows the implications of dark-matter interactions for galaxy evolution to be explored quickly over large volumes of the dark-matter parameter space, and other new physics (e.g., dark-matter self-interactions or anisotropy in the distribution function) is easily incorporated. The code can also provide useful calibrations and benchmarks for fully 3D N-body or hydrodynamical simulations.",
  "abstract_shown": true,
  "affiliations": [],
  "article_type": null,
  "arxiv": "2610.20702",
  "author_total": 3,
  "authors": [
    {
      "name": "Marc Kamionkowski"
    },
    {
      "name": "Vera Gluscevic"
    },
    {
      "name": "Kris Sigurdson"
    }
  ],
  "bibtex": "https://research.draconitic.com/paper/3990r74qbh0fq.bib",
  "cited_by": 0,
  "doi": "10.48550/arxiv.2610.20702",
  "fulltext_url": null,
  "id": "3990r74qbh0fq",
  "issns": [],
  "landing_url": "https://arxiv.org/abs/2610.20702",
  "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.CO"
    ],
    [
      "arxiv",
      "astro-ph.GA"
    ],
    [
      "arxiv",
      "hep-ph"
    ],
    [
      "arxiv",
      "hep-th"
    ],
    [
      "openalex",
      "3103|Galaxies: Formation, Evolution, Phenomena"
    ]
  ],
  "openalex": "W7222551656",
  "pdf_url": "https://arxiv.org/pdf/2610.20702",
  "pmcid": null,
  "pmid": null,
  "published": "2026-10-14",
  "publisher": null,
  "ris": "https://research.draconitic.com/paper/3990r74qbh0fq.ris",
  "sources": [
    {
      "first_seen": "2026-10-30T12:29:50Z",
      "native_id": "2610.20702",
      "source": "arxiv",
      "url": "https://arxiv.org/abs/2610.20702"
    }
  ],
  "subjects": [
    {
      "field": "astronomy",
      "origin": "arxiv:astro-ph.CO",
      "subfield": "cosmology"
    },
    {
      "field": "astronomy",
      "origin": "arxiv:astro-ph.GA",
      "subfield": "galaxies"
    },
    {
      "field": "physics",
      "origin": "arxiv:hep-ph",
      "subfield": "high-energy"
    }
  ],
  "title": "Efficient numerical evolution of self-gravitating systems with dark-matter-baryon scattering",
  "title_text": "Efficient numerical evolution of self-gravitating systems with dark-matter-baryon scattering",
  "type": "preprint",
  "updated_at": "2026-10-30T12:29:50Z",
  "url": "https://research.draconitic.com/paper/3990r74qbh0fq",
  "venue": "arXiv",
  "versions": []
}