TITLE:   GCN CIRCULAR
NUMBER:  13494
SUBJECT: GRB 120716A: Redshift confirmation from VLT/X-shooter
DATE:    12/07/19 16:56:53 GMT
FROM:    Valerio D'Elia at ASDC  <delia@asdc.asi.it>

V. D'Elia (ASDC/INAF-OAR), P. Goldoni (APC,CEA/Irfu),
D. Xu (WIS), T. Kruehler, J. P. U. Fynbo, D. Malesani (DARK/NBI), O.E.  
Hartoog (UvA, Netherland), N. R. Tanvir (U. of Leicester)  
report  on behalf of the X-shooter GRB GTO collaboration:

We observed the GRB 120716A (Hurley et. al GCN 13487) optical counterpart
(Cenko et al. GCN 13489, Xu et al. GCN 13490, Schady et al. GCN 13492) with
X-shooter at the VLT (Paranal, Chile). Observations started on 19 July  
at 8:40 UT
(2.6 days after the burst) and consisted of a total observing
time of 3600 s in each of the UVB, VIS and NIR arms, covering the range
between 3000 and 18000 A.

The spectrum shows a broad absorption trough at ~4250A which we interpret
as due to Lyman-alpha. At the same redshift z=2.486 we detect plenty of metal
absorption lines, such as (CII, SiII, OI, FeII, CIV, SiIV), fine  
structure (CII*, SiII* FeII*) and metastable (NiII) lines.
We thus confirm the redshift reported by Greiner et al. (GCN 13493).


We acknowledge excellent support from the ESO staff, in particular Dimitri
Gadotti, Lorena Faundez, Fernando Selman and Jonathan Smoker.

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