[vsnet-grb-info 6946] GRB 081118: VLT redshift

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  8531
SUBJECT: GRB 081118: VLT redshift
DATE:    08/11/19 05:42:21 GMT
FROM:    Paolo D'Avanzo at INAF-OAB  <paolo.davanzo at brera.inaf.it>

V. D'Elia (INAF-OAR),  C. C. Thoene (INAF-OAB), A. De Ugarte Postigo 
(ESO), P. D'Avanzo, S. Covino (INAF-OAB), S. Piranomonte (INAF-OAR), R. 
Salvaterra (INAF-OAB), G. Chincarini (Univ. Bicocca) report on behalf of 
the MISTICI collaboration:

We observed the optical afterglow candidate of GRB 081118 (D'Avanzo et 
al. GCN 8528; Loew et al. GCN 8529) with the ESO-VLT equipped with the 
FORS2 camera starting on Nov 19.1166 (about 12 hours after the burst) in 
spectroscopic mode. We took 2x30 min spectra covering the range 
4300-9000 Angstrom (based on a preliminary wavelength calibration) with 
a resolution of R=440.

We detect a broad absorption feature around lambda_obs = 4350 Angstrom. 
Interpreting this feature as Ly-alpha absorption the inferred redshift 
is z = 2.58. At this redshift we also detect the SiII (1260), SiII 
(1304), CII (1334), SiIV (1393,1402) doublet, SiII (1526), CIV 
(1548,1550) doublet, FeII (1608), AlII (1670), SiII (1808) and AlIII 
(1854).

We acknowledge support from the ESO staff.