[vsnet-grb-info 5335] GRB 071031: VLT high-resolution spectroscopy

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  7023
SUBJECT: GRB 071031: VLT high-resolution spectroscopy
DATE:    07/10/31 03:19:47 GMT
FROM:    Daniele Malesani at Niels Bohr Inst,Dark Cosmology Center  <malesani at astro.ku.dk>

C. Ledoux (ESO), P. Jakobsson (Univ. Herfordshire), A.O. Jaunsen (Univ. 
Oslo), C.C. Thoene, P.M. Vreeswijk, D. Malesani, J.P.U. Fynbo, J. Hjorth 
(DARK), report on behalf of a larger collaboration:

We observed the optical afterglow of GRB 071031 (Stroh et al., GCN 7020; 
Kruehler et al., GCN 7021; Haislip et al., GCN 7022) with the ESO VLT. 
Observations were triggered automatically in rapid response mode 
starting on 2007 Oct 31 at 01:16 UT (9.3 min after the trigger). We 
secured high- and low-resolution spectroscopy with UVES and FORS2, 
respectively.

 From the detection of a DLA and several metallic lines, including 
fine-structure transitions, we determine the redshift to be z=2.692, 
consistently in the UVES and FORS2 spectra. Further analysis is ongoing.

We acknowledge excellent support from the observing staff at Paranal, in 
particular Stan Stefl and Rachel Gilmour.