V. D'Elia (INAF-OAR/ASI-ASDC), D. Xu (NAOC/CAS), D. Malesani, J. P. U. Fynbo (DARK/NBI), H. Flores (GEPI/Paris obs), K. Wiersema (U. of Leicester) and D. Watson (DARK/NBI) report on behalf of a larger collaboration:
We observed the afterglow of GRB 160314A (D'Elia et al., GCN 19182) with ESO's Very Large Telescope UT2 equipped with X-shooter.
Our observations started at 00:15:42 UT on 2016 March 15, about 12h 45m after the Swift trigger, and consisted of four spectra of 1200 s each. The X-shooter spectra cover the range between 3000 and 21000 AA, and were obtained at a seeing of around 0.7�.
A preliminary analysis of the spectrum shows several emission features at the position of the optical transient (Siegel and D'Elia, GCN 19187; Malesani et al. GCN 19191), which we interpret as emission lines of Halpha, Hbeta, Hgamma, [O III], [O II], [S III] and [N II] from the host galaxy at redshift 0.726. Weak absorption features due to Fe II levels are marginally detected at the same redshift.
We acknowledge the fast and efficient support provided by Paranal staff. In particular we thank Boris Haeussler, Giovanni Carraro, Jose Velasquez, Willem-Jan de Wit and Henri Boffin for their excellent job. We also thank Jens Hoeijmakers for postponing his visitor programme allowing us to perform this observation.