{
  "abstract": "Line intensity mapping (LIM) provides a unique window into the high-redshift universe, but the separation of signals from overlapping emission lines and bright continuum foregrounds remains a central analysis challenge. At millimeter wavelengths in particular, [CII], [CI] and numerous CO transitions overlap with comparable brightness, leading to significant spectral confusion. This work presents a joint likelihood framework that incorporates multi-tracer cross-correlations both between distinct LIM tracers and with external galaxy surveys. By jointly fitting all auto- and cross-spectra between the LIM and galaxy data, this approach combines the spatial and spectral information in each dataset to break degeneracies between overlapping lines and recover individual bias-weighted line intensities at fixed cosmology, even at redshifts where no direct cross-correlation is available. We validate this framework on realistic mocks of an extended SPT-SLIM-like survey spanning 125-175 GHz over 100 deg$^2$, combined with an LSST Y1-like photometric galaxy catalog, and recover CO(2-1) through CO(6-5) and [CI](1-0) over $0.3\\lesssim z\\lesssim4$ in the presence of bright continuum foregrounds. We demonstrate that adding the photometric galaxy data tightens line constraints by a factor of $\\sim$3-4 where the galaxies overlap the lines in redshift, and by $\\sim$20-50\\% at higher redshifts beyond the galaxy coverage, where the gain comes indirectly from constraining the low-redshift interlopers. These results highlight external tracer overlap as a primary consideration when optimizing the frequency coverage and footprint of near-future LIM experiments.",
  "abstract_shown": true,
  "affiliations": [],
  "article_type": null,
  "arxiv": "2610.20467",
  "author_total": 2,
  "authors": [
    {
      "name": "Carlos E. Sierra"
    },
    {
      "name": "Kirit S. Karkare"
    }
  ],
  "bibtex": "https://research.draconitic.com/paper/bkfn8pygyzkjf.bib",
  "cited_by": 0,
  "doi": "10.48550/arxiv.2610.20467",
  "fulltext_url": null,
  "id": "bkfn8pygyzkjf",
  "issns": [],
  "landing_url": "https://arxiv.org/abs/2610.20467",
  "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|Galaxies: Formation, Evolution, Phenomena"
    ]
  ],
  "openalex": "W7221967303",
  "pdf_url": "https://arxiv.org/pdf/2610.20467",
  "pmcid": null,
  "pmid": null,
  "published": "2026-10-14",
  "publisher": null,
  "ris": "https://research.draconitic.com/paper/bkfn8pygyzkjf.ris",
  "sources": [
    {
      "first_seen": "2026-10-30T12:29:31Z",
      "native_id": "2610.20467",
      "source": "arxiv",
      "url": "https://arxiv.org/abs/2610.20467"
    }
  ],
  "subjects": [
    {
      "field": "astronomy",
      "origin": "arxiv:astro-ph.CO",
      "subfield": "cosmology"
    },
    {
      "field": "astronomy",
      "origin": "arxiv:astro-ph.IM",
      "subfield": "instrumentation-methods"
    }
  ],
  "title": "Joint Line Intensity Recovery from Multi-Tracer Cross-Correlations",
  "title_text": "Joint Line Intensity Recovery from Multi-Tracer Cross-Correlations",
  "type": "preprint",
  "updated_at": "2026-10-30T12:29:31Z",
  "url": "https://research.draconitic.com/paper/bkfn8pygyzkjf",
  "venue": "arXiv",
  "versions": []
}