{
  "id": "1406.3352",
  "version": "v1",
  "published": "2014-06-12T20:00:20.000Z",
  "updated": "2014-06-12T20:00:20.000Z",
  "title": "The Alpha-element knee of the Sagittarius Stream",
  "authors": [
    "T. J. L. de Boer",
    "V. Belokurov",
    "T. C. Beers",
    "Y. S. Lee"
  ],
  "comment": "6 pages, 3 figures",
  "categories": [
    "astro-ph.GA"
  ],
  "abstract": "We employ abundances from the Sloan Digital Sky Survey (SDSS) and the Sloan Extension for Galactic Understanding and Exploration (SEGUE) to study the alpha-element distribution of the stellar members of the Sagittarius stream. To test the reliability of SDSS/SEGUE abundances for the study of Sagittarius, we select high-likelihood samples tracing the different components of the Milky Way, and recover known literature alpha-element distributions. Using selection criteria based on the spatial position, radial velocity, distance and colours of individual stars, we obtain a robust sample of Sagittarius-stream stars. The alpha-element distribution of the Sagittarius stream forms a narrow sequence at intermediate metallicities with a clear turn-down, consistent with the presence of an alpha-element \"knee\". This is the first time that the alpha-element knee of the Sagittarius dwarf galaxy has been detected. Fitting a toy model to our data, we determine that the alpha-knee in Sagittarius takes place at [Fe/H]=-1.27pm0.05, only slightly less metal-poor than the knee in the Milky Way. This indicates that a small number of Sagittarius-like galaxies could have contributed significantly to the build-up of the Milky Way's stellar halo system at ancient times.",
  "revisions": [
    {
      "version": "v1",
      "updated": "2014-06-12T20:00:20.000Z"
    }
  ],
  "analyses": {
    "keywords": [
      "sagittarius stream",
      "alpha-element knee",
      "milky ways stellar halo system",
      "sloan digital sky survey",
      "select high-likelihood samples"
    ],
    "tags": [
      "journal article"
    ],
    "publication": {
      "doi": "10.1093/mnras/stu1176",
      "journal": "Monthly Notices of the Royal Astronomical Society",
      "year": 2014,
      "month": "Sep",
      "volume": 443,
      "number": 1,
      "pages": 658
    },
    "note": {
      "typesetting": "TeX",
      "pages": 6,
      "language": "en",
      "license": "arXiv",
      "status": "editable",
      "inspire": 1300735,
      "adsabs": "2014MNRAS.443..658D"
    }
  }
}