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GCN Circular 588

Subject
GRB000301C optical observations
Date
2000-03-05T17:27:05Z (25 years ago)
From
Christian Veillet at CFHT <veillet@cfht.hawaii.edu>
GRB000301c optical observations


The candidate for the optical transient (OT) associated with the gamma ray burst
GRB000301c has been observed in imaging mode with MOS on the 3.6-m CFH Telescope
in the course of the French GRB follow-up program at CFHT (M. Boer, CESR,
C. Veillet, CFHT).

An R image has been taken with a good seeing (better then 0.8 arcsecond).
Relative photometry with respect to the reference star A (GCN573) using 
GCN583 photometry is as following

R = 20.86 +/- 0.04   2000 March 5.63 (UTC)

It is significantly different from the prediction based on a temporal decay 
slope alpha = -1.07 +/- 0.09 (GCB581) and seems to confirm the flattening of the 
decay rate suggested in the same circular. More data would be welcome though!


The relative photometry in B and R published in GCN575 becomes, using GCN583
data:
B = 21.11 +/- 0.04   2000 March 3.50 (UTC)
R = 20.27 +/- 0.04   2000 March 3.51 (UTC)
and B-R = 0.84 +/- 0.06 at the same date, to be compared with 0.77 +/- 0.06 
on March 4.52 (GCN585).


D. Elbaz and H. Flores are acknowledged for their help in these observations.

This message may be cited.


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