Skip to main content
Testing. You are viewing the public testing version of GCN. For the production version, go to
New Announcement Feature, Code of Conduct, Circular Revisions. See news and announcements

GCN Circular 253

GRB19990123 observations
1999-02-08T17:31:10Z (25 years ago)
Christian Veillet at CFHT <>
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 three consecutive
nights on 1999 Feb 5.6, 6.6 and 7.6 by C. Veillet in the course
of the French GRB follow-up program at CFHT (M. Boer, CESR, C. Veillet, CFHT). 

A composite image of the field around the OT has been made
from eighteen 10min exposures (six per night).  Using the standards
published by Nilakshi et al. (GCN 252), the mean R magnitude
of the OT averages to R = 23.45 (0.1) on 1999 Feb 6.6. 
Images of the field, with a detection limit of R=25.0 (3 sigma),
can be seen at the Web site
No object is detected in a radius of 5" centered on the OT. 
This message may be cited.
Looking for U.S. government information and services? Visit