GCN Circular 260
Christian Veillet reports: The optical transient (OT) associated with the gamma ray burst GRB990123 has been observed with the new wide field camera CFH12k at the prime focus of the 3.6-m CFH Telescope for two additional nights on 1999 Feb. 8.6 and 9.6 by C. Veillet in the course of the French GRB follow-up program at CFHT (M. Boer, CESR, C. Veillet, CFHT) with the assistance of J. Anderson (University of Victoria - Canada), as a continuation of the observations reported in GCN 253 from the three previous nights. Using only the last three nights (image quality better than 1 arc-second), photometric measurements in B, V and R using the star #18 published by Nilakshi et al. (GCN 252) give the following results: R = 23.41 (0.1) on 1999 Feb. 8.6 - 130 mn total integration time V = 24.05 (0.1) on 1999 Feb. 8.6 - 50 mn total integration time B = 24.46 (0.15) on 1999 Feb. 9.6 - 30 mn total integration time The V magnitude is in good agreement with the HST estimate of the OT+galaxy magnitude (V~24 GCN 255). As suspected from the first published image based on the first three nights (GCN 253) with the first two of poor image quality, the surrounding galaxy is now clearly resolved. A composite image in R and contour maps of the GRB area and of a nearby comparison star are available at the Web site http://www.cfht.hawaii.edu/~veillet/grb990123.html This message may be cited.