GCN Circular 43132
Subject
GRB 251214B: UAFO optical upper limit
Event
Date
2025-12-15T18:11:38Z (18 hours ago)
From
Alina Volnova at IKI RAS <alinusss@gmail.com>
Via
Web form
N. S. Pankov (HSE, IKI), A. Kochergin (UAFO IAA), A. A. Volnova (IKI), A. S. Pozanenko (IKI) report on behalf of IKI-GRB-FuN:
We observed the field of the long GRB 251214B detected by Fermi (Fermi team, GCN 43088), Swift (Eyles-Ferris et al., GCN 43089; Evans et al., GCN 43098; Kuin and Eyles-Ferris, GCN 43105; Burrows et al., GCN 43112; Laha et al., GCN 43129), and GECAM-B (Luo et al., GCN 43113) with the RC-500 (0.5m) telescope of Ussuriysk Astrophysical Observatory (UAFO) taking several frames in R-band. The observations started on Dec. 14 at 10:44 UT, i.e., ~ 1.5 hours after the Swift/BAT trigger. In the stacked image we do not detect the optical counterpart reported previously (Eyles-Ferris et al., GCN 43089; Kang et al., GCN 43093; Gress et al., GCN 43095; Fu et al., GCN 43097; Gupta et al., GCN 43100; Watson et al., GCN 43103; Kuin and Eyles-Ferris, GCN 43105; Pérez-Fournon et al., GCN 43123; Volnova et al., GCN 43124; de Ugarte Postigo et al., GCN 43131). Photometry and observational details are the following:
Date UT start t-T0 Exp. Filter Obj. Err. UL Site/Telescope
(mid,days) (n*s) (3sigma)
2025-12-14 10:44:26 0.09073 57*60 R n/d n/d 19.4 UAFO/RC500
The photometry is based on several nearby stars from the USNO-B1 catalogue (R2 magnitudes) and is not corrected for the Galactic extinction.