{
  "bibcode": "2025GCN.39427....1P",
  "createdOn": 1740311471808,
  "submitter": "Alexei Pozanenko at IKI, Moscow <grb.alex@gmail.com>",
  "circularId": 39427,
  "body": " N. Pankov (HSE, IKI), V. Kim (FAI), M. Krugov (FAI), Y. Aimuratov (FAI),\nA. Volnova(IKI), A. Pozanenko (IKI) report on behalf of IKI GRB FuN:\n\nWe observed the optical afterglow (Francile et al., GCN 39395; Watson et\nal., GCN 39397; Melandri et al., GCN 39406; Shilling et al., GCN 39409; Guo\net al., GCN 39412; Muenter et al., GCN 39417; Palmerio et al., GCN 39418;\nPankov et al., GCNs 39422,39424; Ghosh et al., GCN 39425) of the Swift GRB\n250221A (Caputo et al., GCN 39396) with AZT-20 telescope of Assy-Turgen\nobservatory starting on 2025-02-22 (UT) 15:01:45 in r' filter.\n\nThe afterglow is clearly detected. Preliminary photometry of the afterglow\nin the stacked image is the following\n\nDate UT start t-T0 Exp. Filter OT Err. UL(3sigma)\n\n2025-02-22 15:01:45 1.49280 45x60 r' 20.50 0.05 22.7\n\nThe photometry is based on nearby PS1 stars.\nCompared to our previous observations (Pankov et al., GCNs 39422, 39424,\n39426) we can confirm the afterglow brightening. We can estimate the time\nof the maximum earlier than 2025-02-22 (UT) 12:29:44\n",
  "subject": "GRB 250221A: continued Assy optical observations, brightening afterglow confirmation",
  "eventId": "GRB 250221A",
  "submittedHow": "email"
}