{
  "bibcode": "2025GCN.39250....1R",
  "eventId": "GRB 250207A",
  "body": "Amit K. Ror, Anshika Gupta, Kiran, Shashi B. Pandey, Kuntal Mishra (ARIES)\nreport:\n\nWe observed the field of GRB 250207A detected by the Swift Burst Alert\nTelescope (Swift team, Ferro et al. 2025; GCN 39182) with the 1.3m\nDevasthal Fast Optical Telescope (DFOT), located at the Devasthal\nObservatory of the Aryabhatta Research Institute of Observational Sciences\n(ARIES), India. The observations were started on 2025-02-07 at 13:41:42 UT,\ni.e., ~ 0.52 days after the Swift-BAT trigger. We have taken multiple\nframes with an exposure time of 300 s in the R filter. We stacked the\nimages after the alignment. We detected an optical afterglow in our stacked\nimage within the error box of the enhanced Swift-XRT position by Osborne et\nal. 2025 (GCN 39217). We obtain the following preliminary magnitude in the\nstacked image:\n\nDate Start_UT T_start-T0 (days) Filter  Exp time (s)  Magnitude\n=========================================================\n2025-02-07 13:41:42     ~0.52     R     300s*4     21.12 +/- 0.15\n\nOur detection is consistent with Angulo et al. 2025 (GCN 39186); Kuin et\nal. 2025 (GCN 39199); Brivio et al. 2025 (GCN 39202); Jelinek et al. 2025\n(GCN 39209) and Ferro et al. 2025 (GCN 39212).\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 catalogue. This circular may be cited.\n",
  "submitter": "Amit Kumar Ror at ARIES <mitturor77894@gmail.com>",
  "circularId": 39250,
  "createdOn": 1739111106328,
  "subject": "GRB 250207A: 1.3m DFOT Optical observations",
  "submittedHow": "email"
}