[AAVSO-HEN] GRB 081222: Gemini-N confirmation of redshift z=2.77

[grb at aavso.org]

The following is a GCN Circular circulated via the AAVSO network.
For an archive and more information on circulars visit:
http://lheawww.gsfc.nasa.gov/docs/gamcosray/legr/bacodine/gcn3_archive.html

TITLE:   GCN CIRCULAR
NUMBER:  8718
SUBJECT: GRB 081222: Gemini-N confirmation of redshift z=2.77
DATE:    08/12/23 20:14:39 GMT
FROM:    John Graham at STScI  <graham at stsci.edu>

J. F. Graham (STScI/JHU), N. R. Tanvir (U. Leicester), A. S. Fruchter 
(STScI), K. Wiersema (U. Leicester), A. J. Levan (U. Warwick) report on 
behalf of a larger collaboration:

We observed the afterglow of GRB 081222 with Gemini-North/GMOS Nod & 
Shuffle spectroscopy beginning 22 Dec 2008 06:38 UT, approximately 105 
minutes post-burst. From absorption lines of SiII, CIV, and FeII, we 
confirm the redshift reported in GCN 8713 (Cucchiara et al.) of z=2.77. 
We also find tentative evidence for a lower redshift system at z=2.74.

We thank the Gemini staff, in particular Ricardo Schiavon, for 
conducting these observations.