{
  "abstract": "Testing General Relativity (GR) on cosmological scales requires probes that are directly sensitive to gravitational dynamics. We present a Fisher matrix forecast of how well the Dark Energy Spectroscopic Instrument (DESI) Bright Galaxy Survey (BGS) can constrain departures from GR through the cluster infall velocity field, using the redshift-space cluster-galaxy cross-correlation function $ξ^{\\rm s}_{\\rm cg}(r_p, r_π)$ as the primary observable. We construct mock catalogs from the AbacusSummit N-body simulations, using a Halo Occupation Distribution (HOD) model for galaxies and a log-normal mass-observable relation for cluster selection. We parameterize departures from GR with a single multiplicative factor $F_{\\rm G}$ that rescales halo infall velocities relative to the GR prediction. Marginalizing over the HOD, mass-observable, and cosmological parameters, we find that DESI BGS can constrain $F_{\\rm G}$ to $σ(F_{\\rm G}) = 0.033$ at $z \\sim 0.3$. This precision is sufficient to distinguish representative $f(R)$ and Galileon gravity models from GR at $\\gtrsim 4σ$. The strongest limitation is a degeneracy between $F_{\\rm G}$ and the scatter in the cluster mass-observable relation, while the constraint shows no strong degeneracy with any individual HOD parameter. Perfect knowledge of the galaxy-halo connection would improve the constraint to $σ(F_{\\rm G}) \\approx 0.015$, and including the galaxy autocorrelation function in the data vector could recover part of this improvement. The same data vector yields tight constraints on the cosmological parameters, $σ(Ω_m) = 0.010$ and $σ(σ_8) = 0.010$, only moderately correlated with $F_{\\rm G}$. These results demonstrate the potential of DESI BGS cluster-galaxy correlations to test gravity on quasi-linear scales, complementary to existing modified gravity probes and to weak-lensing cluster mass profiles.",
  "abstract_shown": true,
  "affiliations": [],
  "article_type": null,
  "arxiv": "2610.37782",
  "author_total": 4,
  "authors": [
    {
      "name": "Nicole Marcelina Gountanis"
    },
    {
      "name": "David H. Weinberg"
    },
    {
      "name": "Andrés N. Salcedo"
    },
    {
      "name": "Claire Lamman"
    }
  ],
  "bibtex": "https://research.draconitic.com/paper/4cv04wfsyabjr.bib",
  "cited_by": 0,
  "doi": "10.48550/arxiv.2610.37782",
  "fulltext_url": null,
  "id": "4cv04wfsyabjr",
  "issns": [],
  "landing_url": "https://arxiv.org/abs/2610.37782",
  "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.CO"
    ],
    [
      "arxiv",
      "gr-qc"
    ]
  ],
  "openalex": null,
  "pdf_url": "https://arxiv.org/pdf/2610.37782",
  "pmcid": null,
  "pmid": null,
  "published": "2026-10-27",
  "publisher": null,
  "ris": "https://research.draconitic.com/paper/4cv04wfsyabjr.ris",
  "sources": [
    {
      "first_seen": "2026-10-30T12:36:23Z",
      "native_id": "2610.37782",
      "source": "arxiv",
      "url": "https://arxiv.org/abs/2610.37782"
    }
  ],
  "subjects": [
    {
      "field": "astronomy",
      "origin": "arxiv:astro-ph.CO",
      "subfield": "cosmology"
    },
    {
      "field": "physics",
      "origin": "arxiv:gr-qc",
      "subfield": "gravitation"
    }
  ],
  "title": "The Redshift-Space Cluster-Galaxy Cross-Correlation as a Probe of Gravity on Cosmic Scales",
  "title_text": "The Redshift-Space Cluster-Galaxy Cross-Correlation as a Probe of Gravity on Cosmic Scales",
  "type": "preprint",
  "updated_at": "2026-11-01T12:20:44Z",
  "url": "https://research.draconitic.com/paper/4cv04wfsyabjr",
  "venue": "arXiv",
  "versions": []
}