TITLE: GCN CIRCULAR NUMBER: 10042 SUBJECT: GRB 091018: VLT/X-shooter spectra DATE: 09/10/19 16:24:15 GMT FROM: Antonio Deugarte at IAA-CSIC A. de Ugarte Postigo (OAB-INAF), P. Goldoni (APC/Univ. Paris 7 and SAp/CEA), C.C. Thoene (OAB-INAF), N. Tanvir (Univ. Leicester), P. Jakobsson (Univ. of Iceland), S.D. Vergani (APC/Univ. Paris 7), H. Flores (Paris Obs.) D. Malesani (DARK/NBI), A. Levan (Univ. Warwick) and J.P.U. Fynbo (DARK/NBI) report on behalf of the X-shooter GRB collaboration: X-shooter observed the afterglow of GRB 091018 (Stamatikos et al. CGN 10034) starting at 23:58 UT of the 18th Oct 2009. The observation consisted of 4 x 600s exposures, having a mean epoch of October 19.0148 UT, 3.53 hours after the burst. In the spectra we detect the continuum in the complete range from 3000 to 24800 Angstroms. On a preliminary analysis we find several absorption features including AlII (1670), AlIII (1854, 1862), FeII (2260, 2344, 2374, 2382, 2586, 2600) MnII (2576, 2594, 2606), MgII (2797, 2803), MgI (2852), CaII (3934, 3969) at a common redshift of 0.9710 +/- 0.0003, consistent with the observation reported by Chen et al. (GCN 10038). There is also a tentative detection of [OII], [OIII] and H-alpha emission lines from the host galaxy at the same redshift. Further analysis is ongoing. We thank the ESO observing staff, in particular A. Smette, C. Martayan and C. Cid.