[AAVSO-HEN] GRB 090118 (BATSS): GRT Optical Observation

[grb at aavso.org]

The following is a GCN Circular circulated via the AAVSO network.
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TITLE:   GCN CIRCULAR
NUMBER:  8830
SUBJECT: GRB 090118 (BATSS): GRT Optical Observation
DATE:    09/01/19 21:50:01 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 the possible GRB 090118 detected by the BAT Slew Survey 
(Copete et al., GCN #8825) with the 14-inch Goddard Robotic Telescope (GRT) 
located at the Goddard Geophysical and Astronomical Observatory  
(http://cddisa.gsfc.nasa.gov/ggao/).   

Thirteen set of 30 sec and 60 sec exposures were taken in the R filter 
starting from Jan. 19 00:38:11 (UT) about 10.5 hr after the trigger.  We 
do not detect the optical afterglow both in the individual images and the 
combined image within the BATSS error circle and also the X-ray source 
found by the Swift/XRT (Rowlinson et al., GCN #8828).  
The estimated three sigma upper limit of the combined image (total 
exposure of 1170 sec) is ~17.6 mag using the USNO-B1 catalog.