GCN Circular 13460
Subject
GRB 120712A: VLT/Xshooter redshift
Event
Date
2012-07-13T03:07:57Z (14 years ago)
From
Dong Xu at Weizmann Inst <dong.dark@gmail.com>
D. Xu (WIS), J. P. U. Fynbo (DARK/NBI), V. D'Elia (ASDC, INAF), N. R.
Tanvir (U. Leicester) report on behalf of the X-shooter GRB GTO
collaboration:
We observed the field of GRB 120712A (Page et al., GCN 13454) with the
ESO VLT equipped with the X-shooter spectrograph. Observations started
at 00:06 UT on 2012-07-13 (10.4 hr after the BAT trigger), for a total
exposure time of ~60 min in each of the UVB, VIS, and NIR arms,
covering the wavelength range 3000-25000A.
The spectrum exhibits a relatively broad trough (centered at ~6292A)
which we interpreted as Lyman-alpha break. Redward of this feature the
spectrum shows metals lines such as Mg II, Si II, and Fe II, all at a
common redshift z=4.1745. We also measured the HI column density,
logN(HI)~20.3, from the Lyman-alpha feature.
We acknowledge the excellent support of the ESO observing staff, in
particular Fernando J. Selman.