TITLE: GCN GRB OBSERVATION REPORT NUMBER: 5489 SUBJECT: GRB 060605, observations using an Integral Field Unit DATE: 06/08/30 10:49:11 GMT FROM: Sylvio Klose at TLS Tautenburg P. Ferrero, S. Klose, D. A. Kann, Thueringer Landessternwarte Tautenburg, P. Boehm, M. M. Roth, AIP Potsdam, S. F. Sanchez, Centro Astronomico Hispano Aleman de Calar Alto, J. Greiner, S. Savaglio, MPE Garching, and N. Masetti, INAF-IASF, Bologna, report: We imaged in 3D the error circle of GRB 060605 using the Integral Field Unit PMAS/PPak (Roth et al. 2005, PASP 117, 620; Kelz et al. 2006, PASP 118, 129) mounted at the Calar Alto 3.5-m telescope. Observations started about 7.5 hours after the burst and were performed with the V300 grating, covering the wavelength region from about 300 to 710 nm. In the spectrum of the optical transient we detect a deep Lyman alpha trough, which was also noted by Peterson & Schmidt 2006 (GCN 5223) and Still et al. 2006 (GCN 5226). We identify absorption lines from Si II, C II and O I at a redshift of z=3.711, which we consider as the redshift of the GRB host galaxy. This message may be quoted.