GCN Circular 23421
Subject
GRB 181110A: VLT/X-shooter redshift
Date
2018-11-11T12:05:33Z (5 years ago)
From
Daniel Perley at Liverpool JMU <d.a.perley@ljmu.ac.uk>
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.