GCN Circular 30478
Subject
GRB 210722A: Assy optical detection
Event
Date
2021-07-22T22:49:40Z (4 years ago)
From
Alexei Pozanenko at IKI, Moscow <apozanen@iki.rssi.ru>
N. Pankov (HSE, IKI), M. Krugov (FAI), A. Pozanenko (IKI), V. Kim (FAI,
Pulkovo Observatory), S. Belkin (IKI) report on behalf of GRB IKI FuN:
We observed the field of GRB 210722A (D'Avanzo et al., GCN 30475) with
AZT-20 telescope of Assy-Turgen observatory starting on 2021-07-22 (UT)
21:42:07. We obtained 30 frames in r' - filter before a twilight.
We clearly detect the bright optical afterglow (D'Avanzo et al., GCN
30475; Zhu et al., GCN 30476) in coordinates of 01:48:07.27
-06:20:50.00 with accuracy of 0.1 arcsec in both coordinates. The
coordinates are coincides with UVOT coordinates (D'Avanzo et al., GCN 30475)
Preliminary photometry of the optical afterglow in the first image of 60
s exposure is following
Date UT start t-T0 Exp. Filter OT Err. UL(3sigma)
(mid, days) (s) (AB)
2021-07-22 21:42:07 0.03293 1*60 r' 16.20 0.03 21.1
The photometry is based on the nearby PS1 stars.