[vsnet-grb-info 10158] GRB 110128A: VLT/X-shooter redshift

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  11607
SUBJECT: GRB 110128A: VLT/X-shooter redshift
DATE:    11/01/28 12:26:53 GMT
FROM:    Nial Tanvir at U.Leicester  <nrt3 at star.le.ac.uk>

M. Sparre, A. de Ugarte Postigo, J. P. U. Fynbo , D. Malesani,
B. Milvang-Jensen (Dark/NBI), S. D. Vergani, H. Flores (GEPI/Obs. de Paris), 
P. Goldoni (APC/Univ. Paris 7 and SAp/CEA), and
N. R. Tanvir (U. Leicester) report on behalf of the X-shooter GRB GTO
collaboration:

We observed the optical afterglow of GRB 110128A (Grupe et al., GCN
11603; de Ugarte Postigo et al., GCN 11605) with the ESO VLT equipped
with X-shooter.

Observations lasted for two hours, with a mean time 2011 Jan 28.345 UT
(6.55 hr after the GRB). Sky transparency was non optimal, but the
seeing was around 0.9".

We detect a broad damped Lyman alpha feature, and other absorption
lines of OI, CII, SiIV, CIV, SiII and FeII at a common redshift of z=2.339. 
We also find an absorption feature at about 4960A which we tentatively
identify as an intervening CIV system at z=2.20.

We acknowledge excellent support from the astronomers at the VLT,
Dieter Nuernberger and Alvaro Alvarez.