{
  "abstract": "Previous radiative transfer calculations have shown that both multi-dimensionality and NLTE (non local thermodynamic equilibrium) effects impact the synthetic observables predicted for Type Ia supernova explosion models. Here we carry out a 2D NLTE radiative transfer simulation in the photospheric phase for a double detonation model with a 1 M⊙ carbon–oxygen core and 0.02 M⊙ helium shell. The predicted observables demonstrate that departures from both spherical symmetry and local thermodynamic equilibrium are significant on scales relevant to comparisons with observations. The NLTE treatment leads to a bluer spectral energy distribution, more slowly declining optical-band light curves, changes to the near-infrared light curve shapes, and differences in the evolution of key spectral features. Although substantial viewing-angle variation is predicted for the model, the scale of the variation is not significantly impacted by NLTE effects up to peak. However, after peak, our 2D NLTE simulation retains a strong viewing-angle dependence in its spectra whereas our simulation of the same ejecta model using an approximate NLTE treatment predicts significantly reduced spectroscopic viewing-angle variation. The NLTE treatment leads to improved agreement with normal Type Ia supernovae, primarily due to the increased ionisation state of the simulation, although the absence of a secondary near-infrared maximum suggests that the ejecta remain over-ionised relative to observations after peak. Despite the improved agreement, many viewing angles still show excessive line blanketing, suggesting that the 0.02 M⊙ helium-shell mass of the current model is too large to reproduce normal Type Ia supernovae over the majority of lines of sight.",
  "abstract_shown": true,
  "affiliations": [
    "School of Mathematics and Physics, Queen’s University Belfast , University Road, Belfast BT7 1NN ,",
    "School of Physics, Trinity College Dublin , The University of Dublin, Dublin 2 ,",
    "Oregon State University Department of Physics, , 301 Weniger Hall, Corvallis, OR 97331-6507 ,",
    "Max-Planck-Institut für Astrophysik , Karl-Schwarzschild-Str. 1, D-85748, Garching ,",
    "Heidelberger Institut für Theoretische Studien , Schloss-Wolfsbrunnenweg 35, D-69118, Heidelberg ,",
    "Zentrum für Astronomie der Universität Heidelberg, Institut für Theoretische Astrophysik , Philosophenweg 12, D-69120 Heidelberg ,",
    "Zentrum für Astronomie der Universität Heidelberg, Astronomisches Rechen-Institut, Mönchhofstr , 12–14, 69120 Heidelberg ,",
    "Research School of Astronomy and Astrophysics, Australian National University , Canberra ACT 2611 ,"
  ],
  "article_type": null,
  "arxiv": null,
  "author_total": 10,
  "authors": [
    {
      "affs": [
        0
      ],
      "name": "F P Callan",
      "orcid": "0000-0002-7975-8185"
    },
    {
      "affs": [
        0
      ],
      "name": "L J Shingles",
      "orcid": "0000-0002-5738-1612"
    },
    {
      "affs": [
        0
      ],
      "name": "S A Sim",
      "orcid": "0000-0002-9774-1192"
    },
    {
      "affs": [
        1
      ],
      "name": "C E Collins",
      "orcid": "0000-0002-0313-7817"
    },
    {
      "affs": [
        2
      ],
      "name": "J M Pollin",
      "orcid": "0009-0005-6989-3198"
    },
    {
      "affs": [
        3
      ],
      "name": "R Pakmor",
      "orcid": "0000-0003-3308-2420"
    },
    {
      "affs": [
        4
      ],
      "name": "S Gronow"
    },
    {
      "affs": [
        4,
        5,
        6
      ],
      "name": "F K Röpke"
    },
    {
      "affs": [
        4
      ],
      "name": "A Holas"
    },
    {
      "affs": [
        7,
        4
      ],
      "name": "I R Seitenzahl",
      "orcid": "0000-0002-5044-2988"
    }
  ],
  "bibtex": "https://research.draconitic.com/paper/cwzmebnfgr00m.bib",
  "cited_by": 0,
  "doi": "10.1093/mnras/stag2038",
  "fulltext_url": null,
  "id": "cwzmebnfgr00m",
  "issns": [
    "0035-8711",
    "1365-2966"
  ],
  "landing_url": "https://academic.oup.com/mnras/advance-article/doi/10.1093/mnras/stag2038/8997909",
  "language": null,
  "licence": "CC-BY-4.0",
  "licence_label": "CC BY 4.0",
  "licence_source": "article",
  "licence_url": "https://creativecommons.org/licenses/by/4.0/",
  "metadata_licence": null,
  "native_subjects": [
    [
      "openalex",
      "3103|Gamma-ray bursts and supernovae"
    ]
  ],
  "openalex": "W7202112215",
  "pdf_url": "https://academic.oup.com/mnras/advance-article-pdf/doi/10.1093/mnras/stag2038/72481619/stag2038.pdf",
  "pmcid": null,
  "pmid": null,
  "published": "2026-10-24",
  "publisher": "Oxford University Press (OUP)",
  "ris": "https://research.draconitic.com/paper/cwzmebnfgr00m.ris",
  "sources": [
    {
      "first_seen": "2026-10-30T12:18:17Z",
      "native_id": "10.1093/mnras/stag2038",
      "source": "crossref",
      "url": "https://academic.oup.com/mnras/advance-article/doi/10.1093/mnras/stag2038/8997909"
    }
  ],
  "subjects": [
    {
      "field": "astronomy",
      "origin": "openalex:3103|Gamma-ray bursts and supernovae",
      "subfield": "high-energy-astrophysics"
    }
  ],
  "title": "Multi-dimensional NLTE radiative transfer for a double detonation Type Ia explosion model in the photospheric phase",
  "title_text": "Multi-dimensional NLTE radiative transfer for a double detonation Type Ia explosion model in the photospheric phase",
  "type": "peer-reviewed",
  "updated_at": "2026-10-30T12:18:17Z",
  "url": "https://research.draconitic.com/paper/cwzmebnfgr00m",
  "venue": "Monthly Notices of the Royal Astronomical Society",
  "versions": []
}