[vsnet-grb-info 13100] GRB 130420A: Redshift from 10.4m GTC

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  14437
SUBJECT: GRB 130420A: Redshift from 10.4m GTC
DATE:    13/04/22 18:33:44 GMT
FROM:    Antonio de Ugarte Postigo at IAA-CSIC  <deugarte at iaa.es>

A. de Ugarte Postigo (IAA-CSIC, DARK/NBI), N. Tanvir (U. Leicester), 
R. Sanchez-Ramirez (IAA-CSIC), C.C. Thoene (IAA-CSIC), 
J. Gorosabel (UPV/EHU, IAA-CSIC), and J. P. U. Fynbo (DARK/NBI) report:

We obtained spectroscopy of the afterglow of GRB 130420A (Page 
et al. GCN 14406) with the 10.4m GTC telescope on the 22nd April 2013,
starting at 03:42 UT (1.84 days after the burst). The observation consisted of 
4x900 s using the R500B grating, with a resolution of R~500 in the range 3600 
- 8700 A.

The spectrum shows an emission line that we identify as [OII] from the host 
and several absorption features that correspond to MgII, MgI, FeII and AlIII at
a common redshift of 1.297, which we identify as the redshift of the GRB.

We also note the presence of an unrelated nearby galaxy (at an angular 
separation of 2.5") which shows emission lines of [OII], H-beta and [OIII] at a 
redshift of 0.584.

We acknowledge the excellent support of the GTC staff.