GCN Circular 42217
Subject
GRB 251003A: Mondy optical upper limit
Event
Date
2025-10-13T14:51:03Z (5 months ago)
From
Alina Volnova at IKI RAS <alinusss@gmail.com>
Via
Web form
A. Volnova (IKI), N. Pankov (HSE, IKI), E. Klunko (ISTP), A. Pozanenko (IKI) report on behalf of IKI-GRB-FuN:
We performed optical observations of the field of GRB 251003A, detected by Fermi (Fermi team, GCNC 42069) and Swift (Beardmore et al., GCNC 42070), in the R-filter with the AZT-33IK 1.5m telescope of the Sayan Solar Observatory (Mondy). The observations began on 2025-10-06 13:10 UT, i.e. ~3.5 days since the trigger and consisted of 90 exposures by 80 s each. The optical source reported previously (Aceituno et al., GCN 42072; Méndez et al., GCN 42073; Strausbaugh et al., GCN 42074; Freeberg et al., GCN 42085; Sanchez-Ramirez et al., GCN 42086; Worssam et al., GCN 42094; Schneider et al., GCN 42095; Mo et al., GCN 42106; Konno et al., GCN 42126) is not detected in the stacked frame. The preliminary photometry is based on nearby USNO-B stars (R2 magnitudes) and is the following:
Date UT start t-T0 Exp. Filter OT Err. UL
(mid, days) (n*s) (3sigma)
2025-10-06 13:10:16 3.50116 90*80 R n/d n/d 22.0