GCN Circular 40049
Subject
GRB 250402A: Mondy optical observations
Event
Date
2025-04-04T14:24:06Z (5 months ago)
From
Alexei Pozanenko at IKI, Moscow <grb.alex@gmail.com>
Via
email
E. Mazaeva (IKI), E. Klunko (ISTP), N. Pankov (HSE), A. Pozanenko (IKI)
report on behalf of IKI GRB-FuN:
We observed GRB 250402A (Chen et al. GCN 40014) with the AZT-33IK telescope
starting on 2025-04-03 (UT) 18:11:28. We found the optical counterpart (Xin
et al., GCN 40015; Pérez-Fournon et al., GCN 40020; Schneider et al., GCN
40022; Magnani et al., GCN 40023) at the position reported by Xin et al.,
GCN 40015.
Preliminary photometry of the optical counterpart is the following
Date UT start t-T0 Filter Exp. OT Err. UL(3sigma)
(mid, days) (s)
2025-04-03 18:11:28 0.81567 R 29*120 21.9 0.2 22.3
The photometry is based on the nearby PS1 stars (R mag by Lupton
transformations).