TITLE: GCN CIRCULAR NUMBER: 7818 SUBJECT: GRB 080604: Gemini-North spectroscopy DATE: 08/06/04 20:46:50 GMT FROM: Klaas Wiersema at U of Leicester K. Wiersema (U. of Leicester), J. Graham (STScI), N. Tanvir, E. Rol (U. of Leicester), A. Levan (U. of Warwick) and A. Fruchter (STScI) report on behalf of a larger collaboration: We observed the optical afterglow of GRB 080604 (GCNC 7800, 7801) with Gemini-North, using the GMOS-N instrument. Spectroscopy was performed with the R400 grism, using 4 x 450 seconds integration time, starting at 2008 June 04, 08:58 UT. Several absorption lines of, among others, Fe II (2382,2586,2600), Mg II (2796,2803) and Mg I (2026,2852) are found at a redshift of 1.416. The discrepancy with respect to the redshift reported in GCN 7805 may be due to provisional calibration files used for the HET reduction (Cucchiara priv. comm.). We thank the Gemini staff astronomers for their support in obtaining these observations.