TITLE: GCN CIRCULAR NUMBER: 23421 SUBJECT: GRB 181110A: VLT/X-shooter redshift DATE: 18/11/11 12:05:33 GMT FROM: Daniel Perley at Liverpool JMU D. A. Perley (LJMU), D. B. Malesani (DAWN/NBI and DARK/NBI), J. P. U. Fynbo (DAWN/NBI and DAWN/DTU), K. E. Heintz (Univ. Iceland), D. A. Kann (HETH/IAA-CSIC), V. D'Elia (SSDC), L. Izzo (HETH/IAA-CSIC), and N. R. Tanvir (Univ. Leicester) report: We observed the optical counterpart of GRB 181110A (Evans et al. GCN 23413; Yamanaka et al., GCN 23414; Murata et al. GCN 23415) with the ESO-VLT UT2 equipped with the X-shooter spectrograph. We acquired four 600 second spectra on UT 2018-11-11 between 00:36 and 01:21, approximately 16 hours after the GRB. The optical afterglow was R~20.4 at this time. Continuum is detected in the reduced spectrum across the entire spectral range of the instrument (blue limit of 3000 Angstroms). Several weak absorption features are also detected: in particular, we identify Mg II and Fe II at a common redshift of z=1.505, identifying this as the most likely redshift of the GRB. An additional intervening system is also identified from (probable) Mg II absorption at z=0.28. We acknowledge the ESO observing staff at Paranal, including Stephane Brillant and Eleonora Sani.