TITLE: GCN CIRCULAR NUMBER: 13441 SUBJECT: GRB 120711A Gemini-S likely redshift DATE: 12/07/11 12:46:35 GMT FROM: Nial Tanvir at U.Leicester N. R. Tanvir, K. Wiersema (U. Leicester), A. J. Levan (U. Warwick), D. Fox (Penn State), A. Fruchter (STScI) and D. Krogsrud (Gemini) report on behalf of a larger collaboration: We observed the afterglow of GRB 120711A (Gotz et al. GCN 12434; Lacluyze et al. GCN 12430) using the GMOS-S spectrograph on Gemini-South. Observations began at 2012-7-11 10:08 UT, about 7.5 hr post-burst. The data were obtained at high air-mass and on the boundary of twilight, so the signal-to-noise is rather poor. Nevertheless, in the spectrum we identify lines of MgII (2797/2804A) and FeII (2374/2383/2587/2600A) at a common redshift of z=1.405. This therefore provides a robust lower-limit to the redshift of the GRB. Furthermore, given the lack of other absorption features, in particular any matching a redshift z~3 (Elliott et al. GCN 13438), we tentatively identify z=1.405 as the most likely GRB redshift.