TITLE: GCN CIRCULAR NUMBER: 10233 SUBJECT: GRB 091127: redshift confirmation with X-shooter DATE: 09/12/02 23:41:17 GMT FROM: Antonio Deugarte at IAA-CSIC C.C. Thoene (INAF-OAB), P. Goldoni (APC/Univ. Paris 7 and SAp/CEA) S. Covino (INAF-OAB), L.A. Antonelli (INAF-OAR), D. Malesani, J.P.U. Fynbo (DARK/NBI), A.J. Levan (U. Warwick), P. Jakobsson (U. Iceland), H. Flores (Paris Obs.), B. Milvang-Jensen, J. Hjorth, D. Watson (DARK/NBI), K. Wiersema, N. R. Tanvir (Univ. Leicester), A. de Ugarte Postigo (INAF-OAB) report on behalf of the X-shooter GRB collaboration: We observed the afterglow of GRB 091127 (Troja et al. GCN 10191, Smith et al. GCN 10192) with X-shooter at the VLT starting at 03:17 UT on Dec 2, 2009. The observation consisted of 4x1500s exposures, with a mean epoch 4.2 days after the burst when the magnitude of the afterglow was R ~ 21 mag (Haislip et al. GCN 10230). We detect the continuum in the range from 3400 to 24800 Angstrom. The S/N in the blue part of the spectrum is low due to the effect of the nearby Moon. In a preliminary analysis using an archival wavelength calibration we detect several emission features superimposed on the afterglow continuum, namely [OII] (3727, 3729), H-beta (4863), [OIII] (4960, 5007) and H-alpha (6563) at a common redshift of 0.49034 +/- 0.00018. This redshift is consistent with the observations reported by Cucchiara et al. (GCN 10202). We do not detect any obvious absorption features at that redshift. We thank the ESO observing staff, in particular H. Korhonen and S. Stefl.