[vsnet-grb-info 12565] GRB 121027A - Gemini South spectroscopy

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  13929
SUBJECT: GRB 121027A - Gemini South spectroscopy
DATE:    12/10/29 23:01:55 GMT
FROM:    Nial Tanvir at U.Leicester  <nrt3 at star.le.ac.uk>

N. R. Tanvir, K. Wiersema (U. Leicester), A. J. Levan (U. Warwick),
R. L. C. Starling (U. Leicester), S. Margheim, T. Hayward (Gemini) report:

We observed the counterpart of GRB 121027A (Starling et al.
GCN 13911; Levan et al. GCN 13920; Sudilovsky et al. GCN13926 ) 
with the GMOS-S spectrograph at Gemini-South, beginning at 
Oct 29 2012 05:42 UT.  The spectrum covers a wavelength range of
roughly 5200A to 7900A, and was obtained in rather
poor conditions.  Our provisional reduction shows a generally featureless
trace, with only one significant absorption feature, at about 7770A.
If we identify this feature with the MgII doublet at 2796/2803A
(the poor S/N and low resolution make it unclear whether or not the
observed line is a doublet), it would imply a redshift of z=1.77.
Whilst this is perhaps the most likely identification, further observations
are encouraged to test this possibility.