{
  "id": "2411.07283",
  "version": "v1",
  "published": "2024-11-11T19:00:01.000Z",
  "updated": "2024-11-11T19:00:01.000Z",
  "title": "Chemo-dynamics of the stellar component of the Sculptor dwarf galaxy I: observed properties",
  "authors": [
    "José María Arroyo-Polonio",
    "Giuseppina Battaglia",
    "Guillaume F. Thomas",
    "Raffaele Pascale",
    "Eline Tolstoy",
    "Carlo Nipoti"
  ],
  "comment": "17 pages, 9 figures, Accepted for publication in Astronomy & Astrophysics",
  "categories": [
    "astro-ph.GA"
  ],
  "abstract": "Aims. Recently, both the presence of multiple stellar chemo-kinematic components and rotation in the Sculptor dwarf spheroidal galaxy have been put into question. Therefore, we re-examine the chemo-kinematic properties of this galaxy making use of the best spectroscopic data-set available containing both line-of-sight velocities and metallicities of individual stars. Methods. We carry out a detailed, quantitative analysis on the recent spectroscopic data-set from Tolstoy et al. (2023) that contains high precision velocities and metallicities for 1339 members of Sculptor. In particular, we assess whether Sculptor is best represented by a single stellar population with a negative metallicity gradient or by the super-position of two or more components with different mean metallicity, spatial distribution and kinematic properties. For this analysis, we also include the incompleteness of the spectroscopic data-set. Results. We find that Sculptor is better described by a two-populations model than by a single-population model with a metallicity gradient. Moreover, given the assumptions of the current modeling, we find evidence of a third population, composed of few stars, that is more extended and metal-poor than the two other populations. This very metal-poor group of stars shows a shift of around 15 km/s in its average l.o.s. velocity (vlos) with respect to the rest of the galaxy. We discuss several possible origins for this new population, finding a minor merger as the most likely one. We also find a vlos gradient of 4.0 +1.5 -1.5 km s-1 deg-1 but its statistical evidence is inconclusive and, moreover, its detection is partially driven by the group of stars with off-set velocities.",
  "revisions": [
    {
      "version": "v1",
      "updated": "2024-11-11T19:00:01.000Z"
    }
  ],
  "analyses": {
    "keywords": [
      "sculptor dwarf galaxy",
      "stellar component",
      "properties",
      "chemo-dynamics",
      "population"
    ],
    "note": {
      "typesetting": "TeX",
      "pages": 17,
      "language": "en",
      "license": "arXiv",
      "status": "editable"
    }
  }
}