[vsnet-grb-info 17278] GRB 151118A iTelescope observation

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  18642
SUBJECT: GRB 151118A iTelescope observation
DATE:    15/11/26 10:03:41 GMT
FROM:    Takanori Sakamoto at AGU  <tsakamoto at phys.aoyama.ac.jp>

Y. Kitaoka, T. Sakamoto, A. Yoshida (AGU) 

We observed the field of GRB 151118A detected by Swift (trigger #664078; 
Amaral-Rogers et al., GCN Circ. 18611) with the iTelescope.Net (http://www.itelescope.net) 
T7 (17" Plane Wave) telescope located at the AstroCamp Observatory (Nerpio, Spain).  
20 images of 60 sec exposures were taken in the R filter starting from November 18 03:45:22 (UT) 
about 38.8 minutes after the trigger and stopped on November 18 04:23:04 (UT).  
We do not detect the optical afterglow both in the individual images and the stacked image 
at the enhanced X-ray afterglow position (Evans et al., GCN Circ. 18614).  The estimated 
five sigma upper limit of the combined image (total exposure of 1200 sec) is ~18.3 using 
the USNO-B1 catalog.