The metallicity and dust content of a redshift 5 gamma-ray burst host galaxy

Research output: Contribution to journalJournal articleResearchpeer-review

  • M. Sparre
  • O. E. Hartoog
  • T. Krühler
  • K. Wiersema
  • V. D'Elia
  • T. Zafar
  • P. M. J. Afonso
  • S. Covino
  • A. de Ugarte Postigo
  • H. Flores
  • P. Goldoni
  • J. Greiner
  • P. Jakobsson
  • L. Kaper
  • S. Klose
  • A. J. Levan
  • B. Milvang-Jensen
  • M. Nardini
  • S. Piranomonte
  • J. Sollerman
  • R. Sánchez-Ramírez
  • S. Schulze
  • N. R. Tanvir
  • S. D. Vergani
  • R. A. M. J. Wijers
Observations of the afterglows of long gamma-ray bursts (GRBs) allow the study of star-forming galaxies across most of cosmic history. Here we present observations of GRB 111008A from which we can measure metallicity, chemical abundance patterns, dust-to-metals ratio and extinction of the GRB host galaxy at z=5.0. The host absorption system is a damped Lyman-alpha absorber (DLA) with a very large neutral hydrogen column density of log N(HI)/cm^(-2) = 22.30 +/- 0.06, and a metallicity of [S/H]= -1.70 +/- 0.10. It is the highest redshift GRB with such a precise metallicity measurement. The presence of fine-structure lines confirms the z=5.0 system as the GRB host galaxy, and makes this the highest redshift where Fe II fine-structure lines have been detected. The afterglow is mildly reddened with A_V = 0.11 +/- 0.04 mag, and the host galaxy has a dust-to-metals ratio which is consistent with being equal to or lower than typical values in the Local Group.
Original languageEnglish
JournalAstrophysical Journal
Issue number2
Pages (from-to)150-161
Number of pages12
Publication statusPublished - 20 Apr 2014

ID: 128853056