TITLE: GCN CIRCULAR NUMBER: 16229 SUBJECT: GRB 140508A: NOT photometry and spectroscopy DATE: 14/05/09 02:30:41 GMT FROM: Daniele Malesani at Dark Cosmology Centre, Niels Bohr Inst D. Malesani, D. Xu (DARK/NBI), P. D'Avanzo (INAF/OAB), E. Palazzi (INAF/IASF Bologna), D. Perna (Obs. Paris) report on behalf of a larger collaboration: We observed the optical afterglow candidate of GRB 140508A (Yu & Goldstein GCN 16224; Hurley et al., GCN 16225; Singer et al., GCN 16226) with the Nordic Optical Telescope (NOT) equipped with ALFOSC. The observation consisted of a 1800 s spectrum covering the wavelength range between 3200 and 9100 AA, carried out at a mean time of 20.63 hr after the GRB. The afterglow is detected in the acquisition image (20.13 hr after the GRB) with r = 19.07+-0.03 (AB) calibrated against SDSS stars. Compared with the measurement by Singer et al. (GCN 16226), our measurement yields a power-law decay slope alpha ~ 1, consistent with the value reported by these authors. We detect several absorption features which we intepret as due to Fe II 2600 and Mg II 2796, 2803 at a common redshift of z = 1.03. This can be considered as a firm lower limit to the GRB redshift, and is consistent with the constraint by Moskvitin et al. (GCN 16228).