TITLE:   GCN CIRCULAR
NUMBER:  31519
SUBJECT: GRB 220118A: TARGET optical upper limit
DATE:    22/01/23 08:08:05 GMT
FROM:    Takanori Sakamoto at AGU  <tsakamoto@phys.aoyama.ac.jp>

Y. Koyanagi, K. Hasuda, T. Sakamoto (AGU)

We observed the field of GRB 220118A detected by Swift
(Klingler et al., GCN Circ. 31490) with The AGU Robotic
Gravitational-wave Electromagnetic Telescope (TARGET)
equipped with the Veloce RH200 (20 cm OTA) and the large
format CCD camera (ATK11000) located at the Machida field
of Aoyama Gakuin University. 20 images of 60 sec exposures
were taken in the R filter starting from January 18
18:25:04 (UT) about 4.4 minutes after the trigger and
stopped on January 18 18:57:56 (UT). We do not detect the
optical afterglow both in the individual images and the
stacked image at the enhanced XRT position (Goad, et al.
GCN Circ. 31495).  The estimated five sigma upper limit of
the combined image (total exposure of 1200 sec)
is ~16.1 mag using the USNO-B1 catalog.