TITLE:   GCN CIRCULAR
NUMBER:  823
SUBJECT: GRB000926 - Optical observations
DATE:    00/09/30 21:14:00 GMT
FROM:    Christian Veillet at CFHT  <veillet@cfht.hawaii.edu>

Content-Type: text/plain; charset=us-ascii
Content-Transfer-Encoding: 7bit

GRB000926 - Optical observations

The optical counterpart of GRB000926 has been observed using the
CFH12K CCD mosaic camera at the prime focus of the 3.6-m CFH
Telescope.

One 600s exposure with moderate seeing (image quality 0.8")
has been obtained and a preliminary reduction using the reference 
star of Halpern et al. (GCN #806) with R=17.1 gives the following 
measurement for GRB000926:

Sept. 30.3075  R = 22.19 +/- 0.06

Added to the R-band data points used in the analysis by Hjorth et al.
(GCN #814), to the previous CFHT observation and to the last data
by Fynbo et al. (GCN #820), this new point confirms the change in decay
rate announced in GCN #820.
The decay value is now 2.44 +/- 0.07, using data past Sept 29.2, while
the decay is 1.67 +/- 0.04 with data prior to Sept 29.2.

A graph of the light curve in R with the linear fits can be found at
http://www.cfht.hawaii.edu/~veillet/grb.html

D. Kocevski, D. Donovan and G. Luppino are acknowledged for their 
help in this observation.

This message may be cited.

-- 
************************************************************
Dr. Christian Veillet,       CFHT Senior Resident Astronomer
Phone: (808) 885-3161   http://www.cfht.hawaii.edu/~veillet/
************************************************************