[vsnet-grb-info 16993] GRB 150910A: Reshift from 10.4m GTC+OSIRIS

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  18274
SUBJECT: GRB 150910A: Reshift from 10.4m GTC+OSIRIS
DATE:    15/09/11 00:17:10 GMT
FROM:    Antonio de Ugarte Postigo at IAA-CSIC  <deugarte at iaa.es>

Antonio de Ugarte Postigo (IAA-CSIC, DARK/NBI), Christina Thoene (IAA-CSIC), 
Gianluca Lombardi (IAC, ULL, GRANTECAN), and Alberto Perez (GRANTECAN) 
report on behalf of a larger collaboration:

We have observed the afterglow of GRB 150910A (Pagani et al., GCN 18264) 
using the 10.4 m GTC telescope equipped with OSIRIS. Our observation began 
at 23:11 UT (14.1 hr after the burst) and consisted of 3x900s exposures using the 
R1000B grism. The spectrum covers the wavelength range between 3700 and 
7800 AA.

The acquisition image shows the afterglow at a magnitude of r=20.65+/-0.07 as 
compared to SDSS stars.

The first spectrum shows a continuum throughout the full spectral range, with 
several absorption features that correspond to AlII, AlIII, FeII, MgII and MgI at a 
common redshift of 1.360, which we interpret as the reshift of the GRB.