GCN Circular 30518
Subject
GRB 210724A: Zeiss-1000 of Koshka observatory, optical upper limit
Event
Date
2021-07-26T12:14:12Z (5 years ago)
From
Alexei Pozanenko at IKI, Moscow <apozanen@iki.rssi.ru>
S. Belkin (IKI), A. Novichonok (Petrozavodsk State University, KIAM),
A. Pozanenko (IKI), A. Zhornichenko (KIAM), N. Pankov (HSE) report
on behalf of IKI GRB FuN:
We observed the field of GRB 210724A (D'Avanzo et al. GCN 30497) with
Zeiss-1000 telescope of Koshka observatory starting on July 24 (UT)
20:39:32. We do not detect any object XRT error circle (D'Avanzo et al.
GCN 30497). We also not detect the object at the position of the
afterglow candidate (Ugarte Postigo et al., GCN 30511).
Preliminary photometry of the field is following
Date UT start t-T0 Filter Exp. OT Err. UL(3sigma)
(mid, days) (s)
2021-07-24 20:39:32 0.024919 R 21*60 n/d n/d 18.6
The photometry is based on the nearby USNO-B1.0 stars
USNO-B1.0_id R2
USNO-B1.0_id R2
0837-0267865 15.24
0836-0268753 16.95
0837-0267827 15.54