{
  "abstract": "The classical density-wave scenario predicts a blue-to-red age–colour gradient across the spiral arms of disc galaxies as a consequence of shock-induced star formation. However, observations of spiral-arm pitch angles at different wavelengths sometimes suggest the opposite trend, namely a red-to-blue “colour jump”. The origin of this apparent contradiction remains unclear. In this work, we investigate the effects of dust attenuation on post-shock stellar emission, together with the streamline motions of gas and stellar populations. We find that dust attenuation in regions with relatively high optical depths, $\\hat{\\tau }_{V} \\gtrsim 0.2$, can produce an apparent red-to-blue spatial sequence, with respect to the shock location, by reversing the relative positions of the flux maxima of stellar populations observed in different bands. Moreover, streamline motions confine post-shock stellar populations near the spiral arms for longer than in a circular-orbit model, thereby modifying the spatial distribution of the emitted light. We conclude that the apparent red-to-blue colour jump does not necessarily contradict the classical density-wave scenario. Instead, it can arise from the same post-shock stellar populations that intrinsically produce a blue-to-red age–colour gradient if their emission is modified by dust attenuation.",
  "abstract_shown": true,
  "affiliations": [
    "Secretaría de Ciencia, Humanidades, Tecnología e Innovación (SECIHTI), Av. Insurgentes Sur 1582 Colonia Crédito Constructor , Benito Juárez, Ciudad de México , , C.P. 03940",
    "Instituto Nacional de Astrofísica, Óptica y Electrónica , Luis E. Erro 1, Tonantzintla, Puebla , , C.P. 72840",
    "Instituto de Radioastronomía y Astrofísica , UNAM, Campus Morelia, Michoacán , , C.P. 58089"
  ],
  "article_type": null,
  "arxiv": null,
  "author_total": 4,
  "authors": [
    {
      "affs": [
        0,
        1
      ],
      "name": "Eric E Martínez-García"
    },
    {
      "affs": [
        2
      ],
      "name": "Rosa A González-Lópezlira"
    },
    {
      "affs": [
        1
      ],
      "name": "Ivânio Puerari"
    },
    {
      "affs": [
        0,
        1
      ],
      "name": "A I Gómez-Ruiz"
    }
  ],
  "bibtex": "https://research.draconitic.com/paper/3cnz4nqvb3ffb.bib",
  "cited_by": 0,
  "doi": "10.1093/mnras/stag2099",
  "fulltext_url": null,
  "id": "3cnz4nqvb3ffb",
  "issns": [
    "0035-8711",
    "1365-2966"
  ],
  "landing_url": "https://academic.oup.com/mnras/advance-article/doi/10.1093/mnras/stag2099/9011269",
  "language": null,
  "licence": "CC-BY-4.0",
  "licence_label": "CC BY 4.0",
  "licence_source": "journal",
  "licence_url": "https://creativecommons.org/licenses/by/4.0/",
  "metadata_licence": null,
  "native_subjects": [],
  "openalex": null,
  "pdf_url": "https://academic.oup.com/mnras/advance-article-pdf/doi/10.1093/mnras/stag2099/72894384/stag2099.pdf",
  "pmcid": null,
  "pmid": null,
  "published": "2026-11-03",
  "publisher": "Oxford University Press (OUP)",
  "ris": "https://research.draconitic.com/paper/3cnz4nqvb3ffb.ris",
  "sources": [
    {
      "first_seen": "2026-11-04T00:22:56Z",
      "native_id": "10.1093/mnras/stag2099",
      "source": "crossref",
      "url": "https://academic.oup.com/mnras/advance-article/doi/10.1093/mnras/stag2099/9011269"
    }
  ],
  "subjects": [
    {
      "field": "astronomy",
      "origin": "journal-openalex:3103|Stellar, planetary, and galactic studies",
      "subfield": "stellar"
    }
  ],
  "title": "Dust-induced reversal of the optical wavelength dependence of spiral-arm pitch angles",
  "title_text": "Dust-induced reversal of the optical wavelength dependence of spiral-arm pitch angles",
  "type": "peer-reviewed",
  "updated_at": "2026-11-05T00:20:45Z",
  "url": "https://research.draconitic.com/paper/3cnz4nqvb3ffb",
  "venue": "Monthly Notices of the Royal Astronomical Society",
  "versions": []
}