{
  "bibcode": "2022GCN.31793....1G",
  "body": "Rahul Gupta, Amit Ror, Amit Kumar, Dimple, Ankur Ghosh, Amar Aryan, Krishan\nChand, S. B. Pandey, and Kuntal Misra (ARIES) report:\n\n\nWe observed the Swift-BAT and Fermi-GBM Sub-Threshold detected GRB 220325A (\nFerro et al., GCN 31787; Wood, GCN 31791) with 1.3m Devasthal Fast\nOptical Telescope\n(DFOT) located at Devasthal observatory of Aryabhatta Research Institute of\nObservational Sciences (ARIES), India. The observations were started on\n2022-03-25 at ~ 22:15 UT, i.e., ~ 5 hours after the BAT trigger. We have\ntaken multiple frames having an exposure time of 300 sec in the R filter.\nWe stacked the images after the alignment. We did not detect any new\noptical source\nwithin the Swift XRT uncertainty circle (Osborne et al., GCN 31790) in our\nstacked image.\n\nWe obtain the following 3-sigma upper limit in the stacked image.\n\nDate Start_UT T_start-T0 (hour) Filter  Exp time (sec)  Limiting magnitude\n====================================================\n2022-03-25 22:15   ~5                 R        300*20            > 21.7\n\n\nThe magnitude is not corrected for the Galactic extinction in the direction\nof the burst. Photometric calibration is performed using the standard stars\nfrom the USNO-B1.0 catalog.\n\nThis circular may be cited.",
  "circularId": 31793,
  "createdOn": 1648287316000,
  "email": "rahulbhu.c157@gmail.com",
  "subject": "GRB 220325A: 1.3m DFOT Optical upper limit",
  "submitter": "Rahul Gupta at ARIES, India  <rahulbhu.c157@gmail.com>",
  "eventId": "GRB 220325A"
}