TITLE: GCN GRB OBSERVATION REPORT NUMBER: 588 SUBJECT: GRB000301C optical observations DATE: 00/03/05 17:27:05 GMT FROM: Christian Veillet at CFHT 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/ ************************************************************