{
  "abstract": "Hot coronae are key regulators in Milky Way (MW)-type galaxy formation and are thought to emerge once a galaxy's dark matter halo crosses a critical mass threshold, $M_{\\mathrm{vir}}\\sim10^{12} {\\mathrm{M}}_\\odot$, so that accretion shocks can heat infalling gas to virial temperatures, $T_{\\mathrm{vir}}$. Here we investigate the roles of stellar feedback and accretion shocks in establishing the circumgalactic medium (CGM) around MW-mass galaxies using the VINTERGATAN cosmological simulation suite. We find that stellar feedback drives the early formation of a hot CGM, with $T_{\\mathrm{CGM}}\\sim T_{\\mathrm{vir}}$. By contrast, in feedback-free simulations, accretion shocks alone do not produce a CGM with comparably high average temperatures at early epochs ($z>2$), independent of gas metallicity. We show that CGM virialisation (defined when halo-gas cooling time exceeds the free-fall time) begins with the emergence of a hot corona ($T>10^5$ K) that can appear as early as $z\\approx3$ at virial radius, $R_{\\mathrm{vir}}$, when feedback is included. This is much earlier than predicted by accretion-shock theory or feedback-free models ($z\\lesssim1$). While accretion shocks alone produce an inside-out virialisation pattern, feedback can alter this behaviour, driving a rapid transition ($\\lesssim0.5$ Gyr) that is either outside-in or nearly simultaneous throughout the halo. Finally, these early-forming coronae are largely stable from formation through to the present day, but can appear to evolve simply because the definition of $R_{\\mathrm{vir}}$ grows with time. This 'CGM pseudo-evolution' is analogous to the pseudo-evolution of dark matter haloes and should be taken into account when interpreting the evolution of hot coronae.",
  "abstract_shown": true,
  "affiliations": [],
  "article_type": null,
  "arxiv": "2610.08931",
  "author_total": 9,
  "authors": [
    {
      "name": "Víctor Rufo-Pastor"
    },
    {
      "name": "Oscar Agertz"
    },
    {
      "name": "Santi Roca-Fábrega"
    },
    {
      "name": "Martin P. Rey"
    },
    {
      "name": "Joss Bland-Hawthorn"
    },
    {
      "name": "Justin I. Read"
    },
    {
      "name": "Thor Tepper-García"
    },
    {
      "name": "Corentin Cadiou"
    },
    {
      "name": "Anatole Storck"
    }
  ],
  "bibtex": "https://research.draconitic.com/paper/29vygt6jnftmp.bib",
  "cited_by": 0,
  "doi": "10.48550/arxiv.2610.08931",
  "fulltext_url": null,
  "id": "29vygt6jnftmp",
  "issns": [],
  "landing_url": "https://arxiv.org/abs/2610.08931",
  "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.GA"
    ],
    [
      "arxiv",
      "physics.comp-ph"
    ]
  ],
  "openalex": null,
  "pdf_url": "https://arxiv.org/pdf/2610.08931",
  "pmcid": null,
  "pmid": null,
  "published": "2026-10-06",
  "publisher": null,
  "ris": "https://research.draconitic.com/paper/29vygt6jnftmp.ris",
  "sources": [
    {
      "first_seen": "2026-10-30T12:27:37Z",
      "native_id": "2610.08931",
      "source": "arxiv",
      "url": "https://arxiv.org/abs/2610.08931"
    }
  ],
  "subjects": [
    {
      "field": "astronomy",
      "origin": "arxiv:astro-ph.GA",
      "subfield": "galaxies"
    },
    {
      "field": "physics",
      "origin": "arxiv:physics.comp-ph",
      "subfield": "computational"
    }
  ],
  "title": "Early onset of the hot circumgalactic medium around Milky Way galaxies",
  "title_text": "Early onset of the hot circumgalactic medium around Milky Way galaxies",
  "type": "preprint",
  "updated_at": "2026-10-30T12:27:37Z",
  "url": "https://research.draconitic.com/paper/29vygt6jnftmp",
  "venue": "arXiv",
  "versions": []
}