GCN Circular 13213
A. Cucchiara (UCSC/UCO Lick), on behalf of a larger collaboration reports: On April 4.58 UT (~60 minutes after the BAT trigger) we observed the field of GRB 120404A (Stratta et al., GCN 13208) using GMOS Spectrograph on the Gemini-North 8-m telescope. The optical afterglow is clearly detected in our r-band acquisition image. We performed 2x900s spectroscopic observations of the optical afterglow using the B600 grating centered at 6500 Angstrom (covering the range 5100-7900 A). The spectrum reveals several absorption features, including FeII2586,2600, MgII2796,2803 at a common redshift of 1.633. Other features indicate at least one MgII intervening system at z=1.101 We therefore suggest that the redshift of GRB 120404A is z=1.633. We thank the Gemini-North staff for their prompt support.