[vsnet-grb-info 8533] GRB 091018: VLT/X-shooter spectra

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  10042
SUBJECT: GRB 091018: VLT/X-shooter spectra
DATE:    09/10/19 16:24:15 GMT
FROM:    Antonio Deugarte at IAA-CSIC  <deugarte at iaa.es>

A. de Ugarte Postigo (OAB-INAF), P. Goldoni
(APC/Univ. Paris 7 and SAp/CEA), C.C. Thoene
(OAB-INAF), N. Tanvir (Univ. Leicester),
P. Jakobsson (Univ. of Iceland), S.D. Vergani
(APC/Univ. Paris 7), H. Flores (Paris Obs.)
D. Malesani (DARK/NBI), A. Levan (Univ.
Warwick) and J.P.U. Fynbo (DARK/NBI) report
on behalf of the X-shooter GRB collaboration:

X-shooter observed the afterglow of GRB 091018
(Stamatikos et al. CGN 10034) starting at 23:58 UT
of the 18th Oct 2009. The observation consisted of
4 x 600s exposures, having a mean epoch of October
19.0148 UT, 3.53 hours after the burst. In the spectra
we detect the continuum in the complete range from
3000 to 24800 Angstroms. On a preliminary analysis
we find several absorption features including AlII
(1670), AlIII (1854, 1862), FeII (2260, 2344, 2374,
2382, 2586, 2600) MnII (2576, 2594, 2606), MgII
(2797, 2803), MgI (2852), CaII (3934, 3969) at a
common redshift of 0.9710 +/- 0.0003, consistent with
the observation reported by Chen et al. (GCN 10038).
There is also a tentative detection of [OII], [OIII] and
H-alpha emission lines from the host galaxy at the
same redshift. Further analysis is ongoing.

We thank the ESO observing staff, in particular A.
Smette, C. Martayan and C. Cid.