TITLE: GCN CIRCULAR NUMBER: 11977 SUBJECT: GRB 110422A: tentative redshift from TNG DATE: 11/04/26 15:51:06 GMT FROM: Daniele Malesani at Dark Cosmology Centre, Niels Bohr Inst D. Malesani (DARK/NBI), D. Fugazza (INAF/Brera), P. D'Avanzo (INAF/Brera), V. D'Elia (ASI/ASDC), A. Melandri (INAF/Brera), S. Piranomonte (INAF/Roma), J.P.U. Fynbo (DARK/NBI), M. Cecconi (INAF/TNG), G. Mainella (INAF/TNG), report on behalf of a larger collaboration: We observed the afterglow of GRB 110422A (Mangano et al., GCN 11957; Klunko et al., GCN 11958) with the Italian TNG located in La Palma. A single 700 s spectroscopic exposure could be taken due to rising humidity (see also Melandri et al., GCN 11963). Observations started on 2011 April 22.998 UT (8.25 hr after the GRB). The adopted grism was LR-B, covering the wavelength range 3600-8200 AA. We detect a clear absorption feature at 4290 AA. Interpreting this as the (unresolved) CIV doublet yields a redshift of z = 1.77. At the same redshift we find a few other lines which we interpret as due to Si IV and Fe II. We thus propose z = 1.77 to be the redshift of GRB 110422A.