[vsnet-grb-info 14094] GRB 131030A: Spectroscopy from 10.4m GTC

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  15408
SUBJECT: GRB 131030A: Spectroscopy from 10.4m GTC
DATE:    13/10/30 22:51:59 GMT
FROM:    Antonio de Ugarte Postigo at IAA-CSIC  <deugarte at iaa.es>

A. de Ugarte Postigo (IAA-CSIC, DARK/NBI), C.C. Thoene (IAA-CSIC),
R. Sanchez-Ramirez (IAA-CSIC), J. Gorosabel (IAA-CSIC), 
J.P.U. Fynbo (DARK/NBI), N.R. Tanvir (U. Leicester) and 
C.A. Alvarez Iglesias (ULL/IAC) report on behalf of a larger collaboration:

We have observed the afterglow of GRB131030A (Troja et al. GCN 15402) 
with the 10.4m GTC telescope at Roque de los Muchachos Observatory (Spain)
starting at 21:50 UT (54 min after the burst). We used the R2000B grism that covers
the range from 3950 to 5700 A at a resolution of ~2200.  

A single 600s exposure reduced with archive calibrations shows a strong trace 
with absorption features of AlIII, ZnII, CrII, NiII, FeII, NiII* and FeII* at a common redshift 
of z=1.295, which we identify as the redshift of the GRB. An additional intervening 
system is seen at z=1.164, with lines of AlIII, FeII and MnII.