[vsnet-grb-info 7204] GRB 090102: GRT Optical Observation

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  8778
SUBJECT: GRB 090102: GRT Optical Observation
DATE:    09/01/04 17:13:41 GMT
FROM:    Takanori Sakamoto at NASA/GSFC  <takanori.sakamoto-1 at nasa.gov>

T. Sakamoto (UMBC/GSFC), D. Donato (ORAU/GSFC), N. Gehrels (GSFC),  
T. Okajima (JHU/GSFC), T. N. Ukwatta (GWU/GSFC), Y. Urata (Saitama U),  
C. Wallace (FGCU) 
  
We observed the field of GRB 090102 detected by Swift (trigger #338895;  
Mangano et al., GCN #8762) with the 14-inch Goddard Robotic Telescope (GRT)  
located at the Goddard Geophysical and Astronomical Observatory  
(http://cddisa.gsfc.nasa.gov/ggao/).   
 
Ten set of 5 sec and five set of 10 sec and 30 sec exposures were taken in  
the R filter starting from Jan. 2 03:11:58 (UT) about 16.2 min after  
the trigger.  We do not detect the optical afterglow (Klotz et al.,  
GCN #8761, Mangano et al., GCN #8762) both in the individual  
images and the combined image.  The estimated three sigma upper limit  
of the combined image (total exposure of 250 sec) is ~17.9 mag using 
the USNO-B1 catalog.