{
  "abstract": "We present BeAR, the Bern Atmospheric Retrieval code and successor of Helios-r, and its new high-resolution cross-correlation framework for emission and transmission spectra. BeAR performs joint retrievals by adding the log-likelihoods of high- and low-resolution data computed from the same model atmosphere. The framework implements established cross-correlation log-likelihoods, with the line-depth scaling either fitted analytically or sampled as a free parameter, their per-pixel generalization, fast model filtering, and model re-injection adapted to this filtering. The forward model and likelihood run entirely on a graphics processing unit (GPU). One forward model takes about 1 ms on an NVIDIA GH200, allowing millions of models per minute on a GPU cluster. In separate retrievals of Gemini South/IGRINS and JWST/NIRSpec dayside spectra of the hot Jupiter WASP-77Ab, BeAR reproduces published abundances, C/O ratios, and metallicities to within 1.5 sigma, the preference for 13CO, and the thermal structure and line contrast to within 1 sigma. The joint retrieval confirms a sub-solar metallicity and a near-solar C/O ratio. A full IGRINS retrieval with 17 free parameters takes 27 to 42 minutes on a single NVIDIA GeForce RTX 5080 or about 14 minutes on eight RTX 4090 GPUs. Injection--recovery tests show that the posteriors underestimate the uncertainties of abundance ratios by about a factor of two.",
  "abstract_shown": true,
  "affiliations": [],
  "article_type": null,
  "arxiv": "2611.08489",
  "author_total": 5,
  "authors": [
    {
      "name": "Esther Wang"
    },
    {
      "name": "Daniel Kitzmann"
    },
    {
      "name": "H. Jens Hoeijmakers"
    },
    {
      "name": "Joost P. Wardenier"
    },
    {
      "name": "Helena Lecoq-Molinos"
    }
  ],
  "bibtex": "https://research.draconitic.com/paper/cys92v2350egf.bib",
  "cited_by": 0,
  "doi": "10.48550/arxiv.2611.08489",
  "fulltext_url": null,
  "id": "cys92v2350egf",
  "issns": [],
  "landing_url": "https://arxiv.org/abs/2611.08489",
  "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.EP"
    ],
    [
      "arxiv",
      "astro-ph.IM"
    ]
  ],
  "openalex": null,
  "pdf_url": "https://arxiv.org/pdf/2611.08489",
  "pmcid": null,
  "pmid": null,
  "published": "2026-11-05",
  "publisher": null,
  "ris": "https://research.draconitic.com/paper/cys92v2350egf.ris",
  "sources": [
    {
      "first_seen": "2026-11-06T18:21:30Z",
      "native_id": "2611.08489",
      "source": "arxiv",
      "url": "https://arxiv.org/abs/2611.08489"
    }
  ],
  "subjects": [
    {
      "field": "astronomy",
      "origin": "arxiv:astro-ph.IM",
      "subfield": "instrumentation-methods"
    },
    {
      "field": "astronomy",
      "origin": "arxiv:astro-ph.EP",
      "subfield": "planetary"
    }
  ],
  "title": "BeAR: The Bern Atmospheric Retrieval code - A GPU-accelerated framework for low-resolution, high-resolution, and joint retrievals of exoplanet atmospheres",
  "title_text": "BeAR: The Bern Atmospheric Retrieval code - A GPU-accelerated framework for low-resolution, high-resolution, and joint retrievals of exoplanet atmospheres",
  "type": "preprint",
  "updated_at": "2026-11-06T18:21:30Z",
  "url": "https://research.draconitic.com/paper/cys92v2350egf",
  "venue": "arXiv",
  "versions": []
}