%0 Journal Article
%T On the Ly-alpha emission from gamma-ray burst host galaxies: evidence for low metallicities
%A J. P. U. Fynbo
%A P. Jakobsson
%A P. Moller
%A J. Hjorth
%A B. Thomsen
%A M. I. Andersen
%A A. S. Fruchter
%A J. Gorosabel
%A S. T. Holland
%A C. Ledoux
%A H. Pedersen
%A J. E. Rhoads
%A M. Weidinger
%A R. A. M. J. Wijers
%J Physics
%D 2003
%I arXiv
%R 10.1051/0004-6361:20030931
%X We report on the results of a search for Ly-alpha emission from the host galaxy of the z=2.140 GRB 011211 and other galaxies in its surrounding field. We detect Ly-alpha emission from the host as well as from six other galaxies in the field. The restframe equivalent width of the Ly-alpha line from the GRB 011211 host is about 21 AA. This is the fifth detection of Ly-alpha emission out of five possible detections from GRB host galaxies, strongly indicating that GRB hosts, at least at high redshifts, are Ly-alpha emitters. This is intriguing as only about 25% of the Lyman-Break selected galaxies at similar redshifts have Ly-alpha emission lines with restframe equivalent width larger than 20 AA. Possible explanations are i) a preference for GRB progenitors to be metal-poor as expected in the collapsar model, ii) an optical afterglow selection bias against dusty hosts, and iii) a higher fraction of Ly-alpha emitters at the faint end of the luminosity function for high-z galaxies. Of these, the current evidence seems to favour i).
%U http://arxiv.org/abs/astro-ph/0306403v1