TITLE: GCN GRB OBSERVATION REPORT NUMBER: 5535 SUBJECT: VLT redshift of GRB 060906 DATE: 06/09/06 18:17:49 GMT FROM: Paul Vreeswijk at ESO Paul Vreeswijk (ESO/Cerro Calan), Pall Jakobsson (Hertfordshire), Cedric Ledoux (ESO), Christina Thoene, Johan Fynbo (DARK) report on behalf of a larger collaboration: We observed the optical afterglow (Cenko et al., GCN 5529) of GRB 060906 detected by Swift (Racusin et al., GCN 5528) with ESO's Very Large Telescope UT2 (Kueyen) at Paranal, Chile. One single FORS1 spectrum with an exposure time of 10min. was taken in twilight, with the 300V grism and a 1" slit, providing a wavelength coverage of 3800-8900 at a resolution of 12 A. We detect a damped Ly alpha line and various other absorption features such as Si II, Si II*, O I, C II, Si IV at a redshift of z=3.685. It's a pleasure to thank the excellent support of the Paranal staff, and in particular that of Claudio Melo, Chris Lidman and Linda Schmidtobreick.