TITLE:   GCN GRB OBSERVATION REPORT
NUMBER:  4667
SUBJECT: GRB 060204b: Keck/LRIS Afterglow Confirmation
DATE:    06/02/05 00:32:49 GMT
FROM:    S. Bradley Cenko at Caltech  <cenko@srl.caltech.edu>

D-S. Moon and S. B. Cenko (Caltech) report on behalf of a larger
collaboration:

We have imaged the field of GRB060204b (Falcone et al., GCN 4655) with the
Low-Resolution Imaging Spectrometer mounted on the 10-m Keck I telescope.
Observations consisted of 12 x 180 s images taken simultaneously in V and
I, beginning approximately 18 minutes after the burst.  We clearly detect
the afterglow candidate proposed by Guidorzi et. al (GCN 4661).
Furthermore, the object fades by approximately 1.4 magnitudes during our
I-band observations, and we therefore confirm that this object is the
afterglow of GRB060204b.  In our first I-band image, the afterlow had a
magnitude of 19.4 +/- 0.3 (calculated with respect to the USNO-B1
catalog).