{
  "id": "1508.06942",
  "version": "v1",
  "published": "2015-08-27T17:18:55.000Z",
  "updated": "2015-08-27T17:18:55.000Z",
  "title": "Variable Stars in Local Group Galaxies. I: Tracing the Early Chemical Enrichment and Radial Gradients in the Sculptor dSph with RR Lyrae Stars",
  "authors": [
    "C. E. Martínez-Vázquez",
    "M. Monelli",
    "G. Bono",
    "P. B. Stetson",
    "I. Ferraro",
    "E. J. Bernard",
    "C. Gallart",
    "G. Fiorentino",
    "G. Iannicola",
    "A. Udalski"
  ],
  "comment": "10 pages, 5 figures, MNRAS accepted",
  "categories": [
    "astro-ph.GA",
    "astro-ph.SR"
  ],
  "abstract": "We identified and characterized the largest (536) RR Lyrae (RRL) sample in a Milky Way dSph satellite (Sculptor) based on optical photometry data collected over $\\sim$24 years. The RRLs display a spread in V-magnitude ($\\sim$0.35 mag) which appears larger than photometric errors and the horizontal branch (HB) luminosity evolution of a mono-metallic population. Using several calibrations of two different reddening free and metal independent Period-Wesenheit relations we provide a new distance estimate $\\mu$=19.62 mag ($\\sigma_{\\mu}$=0.04 mag) that agrees well with literature estimates. We constrained the metallicity distribution of the old population, using the $M_I$ Period-Luminosity relation, and we found that it ranges from -2.3 to -1.5 dex. The current estimate is narrower than suggested by low and intermediate spectroscopy of RGBs ($\\Delta$[Fe/H] $\\le$ 1.5). We also investigated the HB morphology as a function of the galactocentric distance. The HB in the innermost regions is dominated by red HB stars and by RRLs, consistent with a more metal-rich population, while in the outermost regions it is dominated by blue HB stars and RRLs typical of a metal-poor population. Our results suggest that fast chemical evolution occurred in Sculptor, and that the radial gradients were in place at an early epoch.",
  "revisions": [
    {
      "version": "v1",
      "updated": "2015-08-27T17:18:55.000Z"
    }
  ],
  "analyses": {
    "keywords": [
      "local group galaxies",
      "rr lyrae stars",
      "early chemical enrichment",
      "radial gradients",
      "sculptor dsph"
    ],
    "note": {
      "typesetting": "TeX",
      "pages": 10,
      "language": "en",
      "license": "arXiv",
      "status": "editable"
    }
  }
}