GCN Circular 13493
Subject
VLT/FORS2 redshift of GRB120716A
Date
2012-07-19T08:40:51Z (12 years ago)
From
Arne Rau at MPE <arau@mpe.mpg.de>
Jochen Greiner, Arne Rau, Patricia Schady (all MPE), Ivo Saviane (ESO),
and Brad Cenko ( UC Berkeley) report on behalf of a larger collaboration.
We observed the afterglow candidate of GRB 120716A (Hurley et al., GCN
13454; Cenko et al. GCN 13489; Xu et al, GCN 13490; Schady et al. CGN
13492) with the ESO VLT equipped with the FORS2 spectrograph.
Observations with the 600B grism, covering a spectral range of
350-610nm) started at ~06:54 UT on July 19th 2012 (~58.2 hr after the
gamma-ray trigger) and lasted for ~ 1.5hr.
The spectrum shows a prominent, broad absorption trough centered at
~4250A, interpreted as Lyman-alpha, together with numerous metal lines
(SiII, OI, SiIV, CIV) at longer wavelength. We find a common redshift of
these features of z=2.48.