TITLE: GCN CIRCULAR NUMBER: 14685 SUBJECT: GRB 130518A: 10.4m GTC/OSIRIS redshift DATE: 13/05/20 15:32:04 GMT FROM: Alberto Castro-Tirado at Inst.de Astro. de Andalucia R. Sánchez-Ramírez (IAA-CSIC), J. Gorosabel (UPV-EHU, IAA-CSIC), A. J. Castro-Tirado (IAA-CSIC), J. Cepa and G. Gómez-Velarde (IAC), on behalf of a larger collaboration, report: We observed the location of the Fermi GRB 130518A (Xiong et al. GCNC 14674, Omodei et al. GCNC 14675) -also detected by Swift and Konus (Cummings et al. GCNC 14676, Golenetskii et al. GCNC 14677)- with the OSIRIS spectrograph mounted at the 10.4m GTC located at Roque de los Muchachos Observatory (La Palma, Spain). Observations began on May 20.1995 UT (i.e. 38.9 hr post burst). The optical afterglow (Evans et al. GCNC 14678, Troja et al. GCNC 14579) is well detected with the blue (R1000B) grism and in the resulting spectrum we see a strong, broad damped-Lya absorption feature at ~4100A, combined with many metal lines including SII, SiII, CII, SiIV, CIV, FeII, AlII and AlIII at a common redshift of z=2.49. We thank E. Troja and the RATIR Team for providing the ID-chart. [GCN OPS NOTE(20may13): Per author's request, (a) the "40.9 hr post burst" was changed to "38.9 hr post burst", and (b) the "We thank E. Troja" was changed to "We thank E. Troja and the RATIR Team".]