A. de Ugarte Postigo (HETH/IAA-CSIC and DARK/NBI),
N. R. Tanvir (U. Leicester), D. Xu (NAOC), JPU.Fynbo
(DAWN/NBI and DAWN/DTU) report on behalf of the
We observed the optical counterpart of the Swift GRB 190114A
(LaPorte et al. GCN 23677, Siegel et al. GCN 23678) with the
ESO Very Large Telescope UT 2 (Kueyen) equipped with the
X-shooter spectrograph, covering the wavelength range
3500-24000 AA. Observations started on 2019 Jan 14 03:25 UT
(approx 15 min after the GRB).
The spectrum exhibits many absorption features, including
Lya, SII, OI, OI*, SiII, SiII*, CII, CII*, NiII, SiIV, CIV, FeII, FeII*,
AlII, AlIII, ZnII, MgII, MgI, and CaII at a common redshift of
z=3.3765. We conclude that this is the redshift of the GRB. We also
identify an intervening system at a redshift of z=2.6232, characterised
by strong features due to MgII, FeII and AlII.
We acknowledge the expert support from the ESO observing
staff, in particular Elizabeth Bartlett, Trystyn Berg and Juan Carlos
Olivares, and the visiting astronomer, Boris Gaensicke.