{
  "abstract": "The MUSE-DARK survey has reported a highly significant increase of the radial acceleration relation (RAR) scale $a_0$ with redshift over $0.33<z<1.44$, parametrized linearly and described by its authors as phenomenological. We confront the same binned measurements with physically motivated scalings, using the continuous family $a_0(z)=A(1+z)^γ$ as the primary statistic. We find $γ=0.78\\pm0.15$ (statistical, plotted uncertainties read as $1σ$): a redshift-independent scale ($γ=0$) is excluded at $5.3σ$ by a nested test, and the matter-density scaling ($γ=3/2$) at $4.8σ$. Hubble tracking, $a_0(z)\\propto H(z)$, with effective exponent $γ\\simeq1.10$, is consistent with the measurement within $2.1σ$ and is the information-criterion-preferred one-parameter description; its amplitude, $A=(1.40\\pm0.03)\\times10^{-10}$ m s$^{-2}$, lies 17 per cent above the canonical SPARC value, within the latter's systematic-dominated uncertainty. The survey's remark that the evolution is 'faster than $H(z)$' is shown to be anchor-dependent: relative to a floating amplitude the binned growth is, if anything, mildly shallower than $H(z)$. All exponent-based conclusions are invariant under redshift-independent rescalings of $a_0$, and hence robust to common-mode stellar-mass systematics. At current precision, the long-noted coincidence $a_0\\sim cH_0$ survives its first confrontation with direct kinematic measurements at intermediate redshift.",
  "abstract_shown": true,
  "affiliations": [],
  "article_type": "Journal reference: Monthly Notices of the Royal Astronomical Society 551(4), 1-4 (2026)",
  "arxiv": "2609.38796",
  "author_total": 1,
  "authors": [
    {
      "name": "G. T. Alcock"
    }
  ],
  "bibtex": "https://research.draconitic.com/paper/c001waqfqwz3w.bib",
  "cited_by": 0,
  "doi": "10.48550/arxiv.2609.38796",
  "fulltext_url": null,
  "id": "c001waqfqwz3w",
  "issns": [],
  "landing_url": "https://arxiv.org/abs/2609.38796",
  "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",
      "physics.gen-ph"
    ]
  ],
  "openalex": null,
  "pdf_url": "https://arxiv.org/pdf/2609.38796",
  "pmcid": null,
  "pmid": null,
  "published": "2026-09-30",
  "publisher": null,
  "ris": "https://research.draconitic.com/paper/c001waqfqwz3w.ris",
  "sources": [
    {
      "first_seen": "2026-10-30T12:25:49Z",
      "native_id": "2609.38796",
      "source": "arxiv",
      "url": "https://arxiv.org/abs/2609.38796"
    }
  ],
  "subjects": [
    {
      "field": "physics",
      "origin": "arxiv:physics.gen-ph",
      "subfield": "general"
    }
  ],
  "title": "Is the acceleration scale of the radial acceleration relation tracking the cosmic expansion rate?",
  "title_text": "Is the acceleration scale of the radial acceleration relation tracking the cosmic expansion rate?",
  "type": "preprint",
  "updated_at": "2026-10-30T12:25:49Z",
  "url": "https://research.draconitic.com/paper/c001waqfqwz3w",
  "venue": "arXiv",
  "versions": [
    {
      "doi": "10.1093/mnras/stag1485",
      "pid": null,
      "relation": "published-as",
      "title": null,
      "venue": null
    }
  ]
}