GCN Circular 30494
Subject
GRB 210722A: continued Assy optical observations
Event
Date
2021-07-24T12:10:35Z (5 years ago)
From
Alexei Pozanenko at IKI, Moscow <apozanen@iki.rssi.ru>
N. Pankov (HSE, IKI), V. Kim (FAI, Pulkovo Observatory), A. Pozanenko
(IKI), M. Krugov (FAI), S. Belkin (IKI) report on behalf of GRB IKI FuN:
We continue observations of of the field of GRB 210722A (D'Avanzo et
al., GCN 30475; Page et al., GCN 30483; Barthelmy et al. GCN 30489;
Wood et al., GCN30490) with AZT-20 telescope of Assy-Turgen
observatory. We obtained several frames in r' - filter starting on
21-07-23 (UT) 21:34:39. We clearly detect the bright optical afterglow
(D'Avanzo et al., GCN 30475; Zhu et al., GCN 30476; Pankov et al., GCN
30478 & 30488; Kumar et al., GCN 30481; Butler et al., GCN 30484;
Thoene et al., GCN 30487; Jelinek et al., GCN 30492).
Preliminary photometry of the afterglow in the stacked image is following
Date UT start t-T0 Exp. Filter OT Err. UL(3sigma)
(mid, days) (s) (AB)
2021-07-23 21:34:39 1.03677 26*60 r' 20.37 0.07 22.5
The photometry is based on the nearby PS1 stars.
The light curve can still be approximated by a single power law with a
an index of -1.1.