GCN Circular 10038
Hsiao-Wen Chen, Jennifer Helsby (UChicago), Stephen Shectman, Ian Thompson, Jeffrey Crane (Carnegie Observatory) report on behalf of a larger collaboration: "We observed the afterglow of GRB091018 reported by Stamatikos et al. (GCN 10034) and confirmed by Schaefer et al. (GCN10036) using the MagE echellette spectrograph on the Magellan Clay Telescope. The observations started at UT 00:28 on October 19, 2009, ~ 3.5 hours after the inital trigger. We obtained 2x900s exposures. Our preliminary reduction shows that the afterglow spectrum displays strong absorption transitions due to MgII, FeII, MnII at redshift z=0.971, which we tentatively identify as the host redsdhift of the GRB. Further analysis is underway. This message may be cited."