{
  "subject": "GRB 250316A: AbAO AS-32 Optical Upper Limit",
  "circularId": 39760,
  "submittedHow": "web",
  "format": "text/plain",
  "body": "N. Pankov (HSE, IKI), R. Ya. Inasaridze (AbAO), A. Pozanenko (IKI) report on behalf of IKI-GRB-FuN:\n\nWe performed optical observations of the field of GRB 250316A (The Fermi GBM team, GCN 39741; Ronchini et. al, GCN 39744; Evans, GCN 39745; Lipunov et. al, GCN 39747; Kennea et. al, GCN 39750; Bala & Meegan, GCN 39751; Beardmore et. al, GCN 39758) in the R filter with the 0.7-meter AS-32 telescope of the Abastumani Astrophysical Observatory (AbAO). The observations started on (UT) 2025-03-17 00:17:41, i.e. about 0.67 days since trigger. We do not find any new optical source within the error circle of the most probable candidate afterglow Swift XRT #1 (Beardmore et. al, GCN 39758). The preliminary upper limit is as follows:\n\nDate       UT start  t-T0         Exp.    Filter OT  UL(3sigma)\n                     (mid, days)  (s)\n2025-03-17 00:17:41  0.67447      107*60  R      n/d 19.7\n\nThe photometry is based on nearby stars from the USNO-B1.0 catalog (R2 magnitudes) and has not been corrected for the Galactic extinction.",
  "submitter": "Nicolai Pankov at HSE, IKI RAS <colinsergesen@gmail.com>",
  "bibcode": "2025GCN.39760....1P",
  "createdOn": 1742215410185,
  "eventId": "GRB 250316A"
}