{
  "createdOn": 1701955211171,
  "bibcode": "2023GCN.35302....1R",
  "submitter": "Amit Kumar Ror at ARIES <mitturor77894@gmail.com>",
  "body": "Amit K. Ror, Rahul Gupta, Amar Aryan, and Shashi B. Pandey (ARIES) report:\n\nWe observed the field of GRB 231205B detected by Swift (Evans et al. 2023,\nGCN 35269) with the 1.3m Devasthal Fast Optical Telescope (DFOT), located\nat the Devasthal Observatory of the Aryabhatta Research Institute of\nObservational Sciences (ARIES), India. The observations were started on\n2023-12-06 at 13:19:13 UT, i.e., ~ 0.86 days after the BAT trigger. We have\ntaken multiple frames with an exposure time of 300 s in the R filter. We\nstacked the images after the alignment. We did not detect optical afterglow\nin our stacked image within the enhanced Swift-XRT observation error box\n(Osborne et al., 2023, GCN 35275). We obtain the following preliminary\n3-sigma upper limit in the stacked image:\n\n\nDate Start_UT T_start-T0 (days) Filter  Exp time (s)  Limiting magnitude\n=========================================================\n2023-12-06 13:19:13    ~0.86     R     300*36     > 22.6\n\n\nOur non-detection is consistent with Odeh et al. 2023, GCN 35270;\nStrausbaugh et al. 2023, GCN 35278; Jiang et al. 2023, GCN 35280; Jiang et\nal. 2023, GCN 35281; Gendre et al. 2023, GCN 35282; Sasada et al. 2023, GCN\n35284; Adami et al. 2023, GCN 35286; Komesh et al. 2023, GCN 35287; Brivio\net al. 2023, GCN 35289; Malenakova et al. 2023, GCN 35292; and Pankov et\nal. 2023, GCN 35299\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. This circular may be cited.\n",
  "subject": "GRB 231205B: 1.3m DFOT Optical upper limit",
  "eventId": "GRB 231205B",
  "circularId": 35302,
  "submittedHow": "email"
}