[vsnet-grb-info 12675] GRB 121201A: X-shooter redshift

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  14035
SUBJECT: GRB 121201A: X-shooter redshift
DATE:    12/12/02 05:43:10 GMT
FROM:    Antonio de Ugarte Postigo at IAA-CSIC  <deugarte at iaa.es>

R. Sanchez-Ramirez (IAA-CSIC), A. de Ugarte Postigo (IAA-CSIC, DARK/NBI), 
T. Kruehler (DARK/NBI), B. Milvang-Jensen (DARK/NBI), J.P.U. Fynbo (DARK/NBI), 
N. Tanvir (U. Leicester), D. Malesani (DARK/NBI), S. Schulze (PUC & MCSS), 
L. Kaper (U. Amsterdam), H. Flores (Obs. Paris) report on behalf of the X-shooter 
GTO GRB collaboration,

We observed the afterglow of GRB121201A (Yeshov et al., GCN 14025, Kruehler 
et al. GCN 14031) using the X-shooter spectrograph on the VLT (Paranal Observatory, 
Chile). Observations consisted of 4x1200s exposures in the UVB and VIS arms and 
8x600s exposures in the NIR, and started on 2 December 1:17 UT (12.87 hr after the 
burst).

In a preliminary reduction we detect Ly-alpha in emission as well as several 
absorption features (SiIV, CIV, AlII, AlIII) at a common redshift of z=3.385, which we 
identify as the redshift of the GRB.

We acknowledge the excellent support of the VLT staff, in particular G. Carraro.