{
  "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, $\\hatτ_{V} \\gtrsim 0.2$, 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": [],
  "article_type": null,
  "arxiv": "2611.00208",
  "author_total": 4,
  "authors": [
    {
      "name": "Eric E. Martínez-García"
    },
    {
      "name": "Rosa A. González-Lópezlira"
    },
    {
      "name": "Ivânio Puerari"
    },
    {
      "name": "Arturo I. Gómez-Ruiz"
    }
  ],
  "bibtex": "https://research.draconitic.com/paper/5x8p7fccs2g6y.bib",
  "cited_by": 0,
  "doi": "10.48550/arxiv.2611.00208",
  "fulltext_url": null,
  "id": "5x8p7fccs2g6y",
  "issns": [],
  "landing_url": "https://arxiv.org/abs/2611.00208",
  "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.GA"
    ]
  ],
  "openalex": null,
  "pdf_url": "https://arxiv.org/pdf/2611.00208",
  "pmcid": null,
  "pmid": null,
  "published": "2026-11-01",
  "publisher": null,
  "ris": "https://research.draconitic.com/paper/5x8p7fccs2g6y.ris",
  "sources": [
    {
      "first_seen": "2026-11-03T12:20:59Z",
      "native_id": "2611.00208",
      "source": "arxiv",
      "url": "https://arxiv.org/abs/2611.00208"
    }
  ],
  "subjects": [
    {
      "field": "astronomy",
      "origin": "arxiv:astro-ph.CO",
      "subfield": "cosmology"
    },
    {
      "field": "astronomy",
      "origin": "arxiv:astro-ph.GA",
      "subfield": "galaxies"
    }
  ],
  "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": "preprint",
  "updated_at": "2026-11-05T15:20:18Z",
  "url": "https://research.draconitic.com/paper/5x8p7fccs2g6y",
  "venue": "arXiv",
  "versions": []
}