{
  "bibcode": "2022GCN.31519....1K",
  "body": "Y. Koyanagi, K. Hasuda, T. Sakamoto (AGU)\n\nWe observed the field of GRB 220118A detected by Swift\n(Klingler et al., GCN Circ. 31490) 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. 20 images of 60 sec exposures\nwere taken in the R filter starting from January 18\n18:25:04 (UT) about 4.4 minutes after the trigger and\nstopped on January 18 18:57:56 (UT). We do not detect the\noptical afterglow both in the individual images and the\nstacked image at the enhanced XRT position (Goad, et al.\nGCN Circ. 31495).  The estimated five sigma upper limit of\nthe combined image (total exposure of 1200 sec)\nis ~16.1 mag using the USNO-B1 catalog.",
  "circularId": 31519,
  "createdOn": 1642925285000,
  "email": "tsakamoto@phys.aoyama.ac.jp",
  "subject": "GRB 220118A: TARGET optical upper limit",
  "submitter": "Takanori Sakamoto at AGU  <tsakamoto@phys.aoyama.ac.jp>",
  "eventId": "GRB 220118A"
}