{
  "abstract": "Post-reionization 21 cm intensity mapping provides a powerful technique for efficiently mapping the Universe on large scales. The Hydrogen Intensity and Real-time Analysis eXperiment (HIRAX) is a compact and highly redundant radio interferometer designed to exploit this technique. We present a forward modelling pipeline for forecasting a statistical detection of the cosmological 21 cm signal with HIRAX through cross-correlation with an external source catalogue. We simulate the cosmological signal using the halo model and propagate it, together with Galactic and extragalactic foreground emission and instrumental noise, through a model of an early-stage 36-dish HIRAX array configuration. We generate simulated visibilities, apply delay-domain foreground filtering, and construct cross-correlation-ready ringmaps for an observing time of 120 days with a single zenith pointing over the frequency range from 700 to 800 MHz, covering approximately 3547 deg$^2$ of the sky. We investigate the prospects for an early statistical signal detection by stacking these ringmaps at the known three-dimensional positions of sources from an overlapping external survey. Specifically, we quantify how delay-domain foreground filtering, the number of stacking sources, catalogue completeness, and source redshift uncertainties affect the detection significance. We find that redshift precision is the most critical requirement: while spectroscopic redshifts with $σ_z / (1+z) \\sim 0.001$ preserve a significant stacking signal even under realistic foreground filtering and substantial catalogue incompleteness, photometric redshift uncertainties of $σ_z / (1+z) \\sim 0.01$ strongly suppress the signal for realistic delay cutoffs. Applying the framework to a Euclid-like spectroscopic galaxy sample, we recover a minimum signal-to-noise ratio of 11 for our most conservative delay cutoff of 100 ns.",
  "abstract_shown": true,
  "affiliations": [],
  "article_type": null,
  "arxiv": "2610.18981",
  "author_total": 3,
  "authors": [
    {
      "name": "Pascal Hitz"
    },
    {
      "name": "Devin Crichton"
    },
    {
      "name": "Alexandre Refregier"
    }
  ],
  "bibtex": "https://research.draconitic.com/paper/4q05fx6z8wy52.bib",
  "cited_by": 0,
  "doi": "10.48550/arxiv.2610.18981",
  "fulltext_url": null,
  "id": "4q05fx6z8wy52",
  "issns": [],
  "landing_url": "https://arxiv.org/abs/2610.18981",
  "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",
      "astro-ph.IM"
    ],
    [
      "openalex",
      "3103|Radio Astronomy Observations and Technology"
    ]
  ],
  "openalex": "W7221869697",
  "pdf_url": "https://arxiv.org/pdf/2610.18981",
  "pmcid": null,
  "pmid": null,
  "published": "2026-10-13",
  "publisher": null,
  "ris": "https://research.draconitic.com/paper/4q05fx6z8wy52.ris",
  "sources": [
    {
      "first_seen": "2026-10-30T12:29:31Z",
      "native_id": "2610.18981",
      "source": "arxiv",
      "url": "https://arxiv.org/abs/2610.18981"
    }
  ],
  "subjects": [
    {
      "field": "astronomy",
      "origin": "arxiv:astro-ph.CO",
      "subfield": "cosmology"
    },
    {
      "field": "astronomy",
      "origin": "arxiv:astro-ph.IM",
      "subfield": "instrumentation-methods"
    }
  ],
  "title": "Forecasting a Cosmological 21 cm Stacking Detection with Early HIRAX Data",
  "title_text": "Forecasting a Cosmological 21 cm Stacking Detection with Early HIRAX Data",
  "type": "preprint",
  "updated_at": "2026-10-30T12:29:31Z",
  "url": "https://research.draconitic.com/paper/4q05fx6z8wy52",
  "venue": "arXiv",
  "versions": []
}