TITLE:   GCN CIRCULAR
NUMBER:  7791
SUBJECT: GRB 080603: Gemini-North redshift
DATE:    08/06/03 15:29:48 GMT
FROM:    Daniel Perley at U.C. Berkeley  <dperley@astro.berkeley.edu>

D. A. Perley, J. S. Bloom (UC Berkeley), and J. X. Prochaska (UCO/Lick) 
report on behalf of a larger collaboration:

Following the KAIT detection (Chornock et al., GCN 7789) of the 
afterglow candidate of GRB 080603 (Paizis et al., GCN 7790; Gomboc et 
al., GCN 7788) we began a spectroscopic sequence at Gemini-North using 
GMOS.  We acquired 2x1200s longslit exposures starting at UT 13:24.  We 
detect very strong resonance lines of MgII and FeII and the 
fine-structure transitions of FeII which establish the redshift of the 
GRB to be z=1.6880.  In addition, we identify intervening MgII 
absorption systems at z=1.5635 (90% c.l.) and z=1.271 (100% c.l.)

In addition, in a single acquisition exposure starting at UT 13:05:05 
(107 minutes after the trigger) the object has a magnitude (relative to 
USNO B1.0) of R~19.7, suggesting it has not faded significantly since 
the observations of Gomboc et al. (GCN 7788).

We thank Richard McDermid and the Gemini staff and for support.