{
  "subject": "GRB 220117B: TARGET optical upper limit",
  "eventId": "GRB 220117B",
  "bibcode": "2022GCN.31518....1K",
  "createdOn": 1642925189000,
  "circularId": 31518,
  "submitter": "Takanori Sakamoto at AGU  <tsakamoto@phys.aoyama.ac.jp>",
  "email": "tsakamoto@phys.aoyama.ac.jp",
  "body": "Y. Koyanagi, K. Hasuda, T. Sakamoto (AGU)\n\nWe observed the field of GRB 220117B detected by Swift\n(Melandri et al., GCN Circ. 31468) with The AGU Robotic\nGravitational-wave Electromagnetic Telescope (TARGET)\nequipped with the Veloce RH200 (20 cm OTA) and the large\nformat CCD camera (ATK11000) located at the Machida field\nof Aoyama Gakuin University. 18 images of 60 sec exposures\nwere taken in the R filter starting from January 17\n20:08:41 (UT) about 3.2 minutes after the trigger and\nstopped on January 17 20:41:42 (UT). We do not detect the\noptical afterglow both in the individual images and the\nstacked image at the enhanced XRT position (Evans, et al.\nGCN Circ. 31473).  The estimated five sigma upper limit of\nthe combined image (total exposure of 1080 sec)\nis ~15.3 mag using the USNO-B1 catalog."
}