{
  "abstract": "Context: Massive early-type galaxies (ETGs) are traditionally considered \"red-and-dead\" based on optical observations. However, ultraviolet (UV) spectroscopy can uncover a hidden population of young stars with a sub-one-per cent mass fraction. Aims: We measure the young stellar mass fraction in NGC 3115, a massive isolated lenticular galaxy, to test the ubiquity and spatial distribution of this component beyond previously studied ellipticals. Methods: Using SOAR/Goodman spectra and line-strength fitting, we modelled the star-formation history with a single bulk stellar population plus a young component (constant star-formation over the last 1 Gyr). We used ultranest to derive posterior distributions for age, metallicity, [Mg/Fe], and the young stellar mass fraction. Results: By tracking spatial variations in U-band indices, we found the young stellar mass fraction peaks at $0.69^{+0.09}_{-0.15}\\%$ in the centre, dropping to zero beyond 1 kpc. This young component correlates with kinematic structures, dominating in the pressure-supported region. We interpret this as residual central star formation fueled by internal processes, such as recycled stellar material. Alternative UV-bright models (e.g., extreme horizontal branch stars) yielded poorer fits and unphysically high mass fractions. Conclusions: Young stars in old, \"red-and-dead\" galaxies are more common than expected. Their presence across various ETGs with similar gradients indicates that residual star formation is a ubiquitous feature, offering key constraints on the baryon cycle in these galaxies.",
  "abstract_shown": true,
  "affiliations": [],
  "article_type": null,
  "arxiv": "2610.37774",
  "author_total": 6,
  "authors": [
    {
      "name": "João P. V. Benedetti"
    },
    {
      "name": "Alexandre Vazdekis"
    },
    {
      "name": "Anna Ferré-Mateu"
    },
    {
      "name": "Elham Eftekhari"
    },
    {
      "name": "Alberto Rodríguez-Ardila"
    },
    {
      "name": "Rogério Riffel"
    }
  ],
  "bibtex": "https://research.draconitic.com/paper/956yp6jm232r3.bib",
  "cited_by": 0,
  "doi": "10.48550/arxiv.2610.37774",
  "fulltext_url": null,
  "id": "956yp6jm232r3",
  "issns": [],
  "landing_url": "https://arxiv.org/abs/2610.37774",
  "language": null,
  "licence": "CC-BY-NC-SA-4.0",
  "licence_label": "CC BY-NC-SA 4.0",
  "licence_source": "article",
  "licence_url": "http://creativecommons.org/licenses/by-nc-sa/4.0/",
  "metadata_licence": "CC0-1.0",
  "native_subjects": [
    [
      "arxiv",
      "astro-ph.GA"
    ]
  ],
  "openalex": null,
  "pdf_url": "https://arxiv.org/pdf/2610.37774",
  "pmcid": null,
  "pmid": null,
  "published": "2026-10-27",
  "publisher": null,
  "ris": "https://research.draconitic.com/paper/956yp6jm232r3.ris",
  "sources": [
    {
      "first_seen": "2026-10-30T12:36:23Z",
      "native_id": "2610.37774",
      "source": "arxiv",
      "url": "https://arxiv.org/abs/2610.37774"
    }
  ],
  "subjects": [
    {
      "field": "astronomy",
      "origin": "arxiv:astro-ph.GA",
      "subfield": "galaxies"
    }
  ],
  "title": "Not so dead after all: young stars in the massive S0 NGC 3115",
  "title_text": "Not so dead after all: young stars in the massive S0 NGC 3115",
  "type": "preprint",
  "updated_at": "2026-11-01T12:20:44Z",
  "url": "https://research.draconitic.com/paper/956yp6jm232r3",
  "venue": "arXiv",
  "versions": []
}