GCN Circular 30384
Subject
GRB 210704A: Assy optical afterglow candidate
Event
Date
2021-07-05T20:32:34Z (4 years ago)
From
Alexei Pozanenko at IKI, Moscow <apozanen@iki.rssi.ru>
V. Kim (FAI, Pulkovo Observatory), A. Pozanenko (IKI), M. Krugov (FAI),
S. Belkin (IKI), N. Pankov (HSE, IKI) report on behalf of GRB IKI FuN:
We observed the field of GRB 210704A Fermi-LAT (Berretta et al. 2021,
GCN 30375), AGILE/MCAL (Ursi et al. 2021, GCN 30372), AstroSat/CZTI
(Prasad et al. 2021, GCN 30378), Swift/XRT (D'Ai et al. GCN 30379), and
Fermi-GBM (Malacaria et al. GCN 30380) with AZT-20 telescope of
Assy-Turgen observatory starting on 2021-07-05 (UT) 17:42:41.27.
In a stacked image we detect only one object near enhanced XRT position
(D'Ai et al. GCN 30379). Coordinates of the object are (J2000)
10:36:04.88 +57:12:58.5 with uncertainty of 0.5 arcsec in both coordinates.
Preliminary photometry of the object is following
Date UT start t-T0 Exp. Filter OT Err. UL(3sigma)
(mid, days) (s)
2021-07-05 17:42:41.27 0.94407 66*60 r' 22.25 0.13 23.0
The photometry is based on the nearby SDSS-DR12 stars.
The object is not presented in the SDSS DR12, nor in PS1 catalogue. We
suggest the object is the afterglow of GRB 210704A.