TITLE: GCN GRB OBSERVATION REPORT NUMBER: 3924 SUBJECT: GRB 050904: photometric redshift DATE: 05/09/05 18:55:57 GMT FROM: Daniele Malesani at SISSA-ISAS,Trieste,Italy L.A. Antonelli, A. Grazian (INAF/OAR), P. D'Avanzo (INAF/OABr), V. Testa (INAF/OAR), S. Covino, G. Tagliaferri, G. Chincarini (INAF/OABr), A. Fernandez-Soto (Univ. Valencia), D. Malesani (SISSA), F. Fiore and L. Stella (INAF/OAR) report on behalf of the MISTICI collaboration: "We observed the field of GRB 050904 (Cummings et al., GCN 3910; Mineo et al., GCN 3920) with the ESO VLT-UT1, in the J, H, and K bands (with ISAAC) and in the I band (with FORS2). The afterglow (Haislip et al., GCN 3913; D'Avanzo et al., GCN 3921) is detected in all filters, including the I band. We derive for this source a photometric redshift z = 6.10 (+0.37, -0.12; 90% confidence) by adopting a chi square minimization technique (Fontana et al., 2000, AJ, 120, 2206). This is in agreement with the result of Haislip et al. (GCN 3919). This message can be cited."