GCN Circular 14437
A. de Ugarte Postigo (IAA-CSIC, DARK/NBI), N. Tanvir (U. Leicester), R. Sanchez-Ramirez (IAA-CSIC), C.C. Thoene (IAA-CSIC), J. Gorosabel (UPV/EHU, IAA-CSIC), and J. P. U. Fynbo (DARK/NBI) report: We obtained spectroscopy of the afterglow of GRB 130420A (Page et al. GCN 14406) with the 10.4m GTC telescope on the 22nd April 2013, starting at 03:42 UT (1.84 days after the burst). The observation consisted of 4x900 s using the R500B grating, with a resolution of R~500 in the range 3600 - 8700 A. The spectrum shows an emission line that we identify as [OII] from the host and several absorption features that correspond to MgII, MgI, FeII and AlIII at a common redshift of 1.297, which we identify as the redshift of the GRB. We also note the presence of an unrelated nearby galaxy (at an angular separation of 2.5") which shows emission lines of [OII], H-beta and [OIII] at a redshift of 0.584. We acknowledge the excellent support of the GTC staff.