a damped Ly$\alpha$ absorber (log $(N_{\mathrm{H\,{\sc I}}}/$cm$^{-2})=21.90\pm0.10$) with a low metallicity (\[X/H$]=-1.21\pm0.16$), likely associated with the interstellar medium of the GRB host galaxy ($z=2.641$).\
author:
- 'A. De Cia$^{1}$, P. Jakobsson$^{1}$, G. Björnsson$^{1}$, P. M. Vreeswijk$^{1,2}$, V. S. Dhillon$^{3}$,'
- 'T. R. Marsh$^{4}$, R. Chapman$^{1,5}$, J. P. U. Fynbo$^{2}$, C. Ledoux$^{6}$, S. P. Littlefair$^{3}$,'
- |
    D. Malesani$^{2}$, S. Schulze$^{1}$, A. Smette$^{6}$, T. Zafar$^{2}$ and E. H. Gudmundsson$^{1}$.\
    $^{1}$ Centre for Astrophysics and Cosmology, Science Institute, University of Iceland, Dunhaga 5, IS-107 Reykjavik, Iceland\
    $^{2}$ Dark Cosmology Centre, Niels Bohr Institute, University of Copenhagen, 2100 Copenhagen Ø, Denmark\
    $^{3}$ Department of Physics and Astronomy, University of Sheffield, Sheffield S3 7RH, UK\
    $^{4}$ Department of Physics, University of Warwick, Coventry CV4 7AL, UK\
    $^{5}$ Centre for Astrophysics Research, University of Hertfordshire, College Lane, Hatfield AL10 9AB, UK\
    $^{6}$ European Southern Observatory, Alonso de Córdova 3107, Vitacura, Casilla 19001, Santiago 19, Chile\
date: 'Accepted 2010 Mm gg. Received 2010 Mm gg; in original form 2010 Mm gg'
title: 'Probing GRB environments with time variability: ULTRASPEC fast imaging of [^1]'
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gamma-rays: bursts - instrumentation: detectors - dust, extinction - ISM: kinematics - ISM: abundances

Introduction
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[ l l c c 