GCN Circular 39426
Subject
GRB 250221A: continued Mondy optical observations, brightening afterglow
Date
2025-02-23T11:47:30Z (22 days ago)
From
Alexei Pozanenko at IKI, Moscow <grb.alex@gmail.com>
Via
email
N. Pankov (HSE, IKI), A. Pozanenko (IKI), E. Klunlo (ISZF), A. Volnova
(IKI) report on behalf of IKI GRB FuN:
We observed the optical afterglow (Francile et al., GCN 39395; Watson et
al., GCN 39397; Melandri et al., GCN 39406; Shilling et al., GCN 39409; Guo
et al., GCN 39412; Muenter et al., GCN 39417; Palmerio et al., GCN 39418;
Pankov et al., GCNs 39422,39424; Ghosh et al., GCN 39425) of the Swift GRB
250221A (Caputo et al., GCN 39396) with AZT-33IK telescope of Mondy
observatory starting on 2025-02-22 (UT) 12:29:44 in R filter.
The afterglow is clearly detected. Preliminary photometry of the afterglow
in the stacked image is the following
Date UT start t-T0 Exp. Filter OT Err. UL(3sigma)
2025-02-22 12:29:44 1.38790 18x120 R 19.95 0.05 21.6
The photometry is based on nearby USNO-B1.0 (R2) stars.
Compared to our previous observations (Pankov et al., GCNs 39422,39424) the
afterglow has apparently become brighter.