{
  "id": "1408.3578",
  "version": "v2",
  "published": "2014-08-15T16:08:39.000Z",
  "updated": "2015-03-03T17:52:18.000Z",
  "title": "Unveiling the Secrets of Metallicity and Massive Star Formation Using DLAs along Gamma-ray Bursts",
  "authors": [
    "A. Cucchiara",
    "M. Fumagalli",
    "M. Rafelski",
    "D. Kocevski",
    "J. X. Prochaska",
    "R. J. Cooke",
    "G. D. Becker"
  ],
  "comment": "28 pages, 4 figures, Accepted on ApJ",
  "categories": [
    "astro-ph.GA",
    "astro-ph.CO",
    "astro-ph.HE"
  ],
  "abstract": "We present the largest, publicly available, sample of Damped Lyman-$\\alpha$ systems (DLAs) along Gamma-ray Bursts (GRB) line of sights in order to investigate the environmental properties of long GRBs in the $z=1.8-6$ redshift range. Compared with the most recent quasar DLAs sample (QSO-DLA), our analysis shows that GRB-DLAs probe a more metal enriched environment at $z\\gtrsim3$, up to $[X/H]\\sim-0.5$. In the $z=2-3$ redshift range, despite the large number of lower limits, there are hints that the two populations may be more similar (only at 90\\% significance level). Also at \\hiz, the GRB-DLA average metallicity seems to decline at a shallower rate than the QSO-DLAs: GRB-DLA hosts may be polluted with metals at least as far as $\\sim 2$kpc from the GRB explosion site, probably due to previous star-formation episodes and/or supernovae explosions. This shallow metallicity trend, extended now up to $z\\sim5$, confirms previous results that GRB hosts are star-forming and have, on average, higher metallicity than the general QSO-DLA population. Finally, our metallicity measurements are broadly consistent with the hypothesis of two channels of GRB progenitors, one of which is mildly affected by a metallicity bias. The metallicity evolution of modeled GRB hosts agrees reasonably well with our data up to intermediate redshift, while more data are needed to constrain the models at $z\\gtrsim 4$.",
  "revisions": [
    {
      "version": "v1",
      "updated": "2014-08-15T16:08:39.000Z",
      "comment": "28 pages, 4 figures",
      "journal": null,
      "doi": null
    },
    {
      "version": "v2",
      "updated": "2015-03-03T17:52:18.000Z"
    }
  ],
  "analyses": {
    "keywords": [
      "massive star formation",
      "gamma-ray bursts",
      "grb hosts agrees reasonably",
      "redshift range",
      "grb explosion site"
    ],
    "publication": {
      "doi": "10.1088/0004-637X/804/1/51",
      "journal": "The Astrophysical Journal",
      "year": 2015,
      "month": "May",
      "volume": 804,
      "number": 1,
      "pages": 51
    },
    "note": {
      "typesetting": "TeX",
      "pages": 28,
      "language": "en",
      "license": "arXiv",
      "status": "editable",
      "inspire": 1311206,
      "adsabs": "2015ApJ...804...51C"
    }
  }
}