{
  "id": "1502.03449",
  "version": "v1",
  "published": "2015-02-11T21:01:02.000Z",
  "updated": "2015-02-11T21:01:02.000Z",
  "title": "The Initial Mass Function of Early-type Galaxies: no correlation with [Mg/Fe]",
  "authors": [
    "F. La Barbera",
    "I. Ferreras",
    "A. Vazdekis"
  ],
  "comment": "5 pages, 2 figures, 2 tables. MNRAS Letters, in press",
  "categories": [
    "astro-ph.GA"
  ],
  "abstract": "The Initial Mass Function (IMF) of early-type galaxies (ETGs) has been found to feature systematic variations by both dynamical and spectroscopic studies. In particular, spectral line strengths, based on gravity-sensitive features, suggest an excess of low-mass stars in massive ETGs, i.e. a bottom-heavy IMF. The physical drivers of IMF variations are currently unknown. The abundance ratio of alpha elements, such as [Mg/Fe], has been suggested as a possible driver of the IMF changes, although dynamical constraints do not support this claim. In this letter, we take advantage of the large SDSS database. Our sample comprises 24,781 high-quality spectra, covering a large range in velocity dispersion (100<sigma0<320 km/s) and abundance ratio (-0.1<[Mg/Fe]<+0.4). The large volume of data allows us to stack the spectra at fixed values of sigma0 and [Mg/Fe]. Our analysis -- based on gravity-sensitive line strengths -- gives a strong correlation with central velocity dispersion and a negligible variation with [Mg/Fe] at fixed sigma0. This result is robust against individual elemental abundance variations, and seems not to raise any apparent inconsistency with the alternative method based on galaxy dynamics.",
  "revisions": [
    {
      "version": "v1",
      "updated": "2015-02-11T21:01:02.000Z"
    }
  ],
  "analyses": {
    "keywords": [
      "initial mass function",
      "early-type galaxies",
      "correlation",
      "individual elemental abundance variations",
      "abundance ratio"
    ],
    "note": {
      "typesetting": "TeX",
      "pages": 5,
      "language": "en",
      "license": "arXiv",
      "status": "editable"
    }
  }
}