{
  "annotation_id": "c423d980-885c-4732-8c6e-54b6491b314c",
  "date_created": "2026-02-17T05:53:12.647000Z",
  "date_modified": "2026-02-17T05:53:12.647000Z",
  "file_hash": "d4a408c6c26f55cfa115214cf9758b1fddf9c6d79a8c8d7ac4b2e7324bd03736",
  "private": false,
  "record": {
    "abstract": "We explore the formation of intermediate mass black holes (IMBHs), potential seeds for supermassive black holes (SMBHs), via runaway stellar collisions for a wide range of star cluster (surface) densities ($4\\times10^3 M_\\odot$ pc$^{-2} \\lesssim \\Sigma_\\mathrm{h}$ $\\lesssim 4\\times10^6 M_\\odot$ pc$^{-2}$) and metallicities ($0.01 Z_\\odot \\lesssim Z \\lesssim 1.0 Z_\\odot)$. Our sample of isolated $(\u003e1400)$ and hierarchical ($30$) simulations of young, massive star clusters with up to $N=1.8\\times10^6$ stars includes collisional stellar dynamics, stellar evolution, and post-Newtonian equations of motion for black holes using the BIFROST code. High stellar wind rates suppress IMBH formation at high metallicities $(Z \\gtrsim 0.2 Z_\\odot)$ and low collision rates prevent their formation at low densities ($\\Sigma_\\mathrm{h} \\lesssim 3\\times10^4 M_\\odot$ pc$^{-2}$). The assumptions about stellar wind loss rates strongly affect the maximum final IMBH masses $(M_\\bullet \\sim 6000 M_\\odot$ vs. $25000 M_\\odot$). The total stellar mass loss from collisions and collisionally boosted winds before $t=3$ Myr can together reach up to 5-10% of the final cluster mass. We present fitting formulae for IMBH masses as a function of host star cluster $\\Sigma_\\mathrm{h}$ and Z, and formulate a model for the cosmic IMBH formation rate density. Depending on the cluster birth densities, the IMBH formation rates peak at $z\\sim2$-$4$ at up to $\\sim10^{-7}$ yr$^{-1}$cMpc$^{-3}$. As more than 50% form below $z\\lesssim1.5$-$3$, the model challenges a view in which all local IMBHs are failed early Universe SMBH seeds.",
    "arxiv_id": "2601.07917",
    "authors": [
      "Antti Rantala",
      "Thorsten Naab",
      "Natalia Lah\u00e9n",
      "Klaus Reuter",
      "Markus Rampp",
      "Martyna Chru\u015bli\u0144ska",
      "Basti\u00e1n Reinoso"
    ],
    "categories": [
      "astro-ph.GA"
    ],
    "license": "http://creativecommons.org/licenses/by/4.0/",
    "title": "FROST-CLUSTERS -- III. Metallicity-dependent intermediate mass black hole formation by runaway collisions in dense star clusters",
    "url": "https://arxiv.org/abs/2601.07917",
    "version": "v1"
  },
  "schema_id": "dorsal/arxiv",
  "source": {
    "execution_id": "9ac9f97c-6339-4e71-b973-ef00b2058206",
    "id": "arXiv Dataset",
    "type": "Model",
    "variant": "snapshot-2026-01-17",
    "version": "0.1.0"
  },
  "user_id": 1000002
}