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
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