GCN Circular 29341
Subject
GRB 210120A(MASTER OT J105242.66+152355.0 / AT2021axc): Mondy optical observations
Event
Date
2021-01-21T09:08:59Z (5 years ago)
From
Alexei Pozanenko at IKI, Moscow <apozanen@iki.rssi.ru>
S. Belkin (IKI), A. Pozanenko (IKI), N. Pankov (HSE), E. Klunko (ISTP)
report on behalf of GRB IKI FuN:
We observed the MASTER OT J105242.66+152355.0 / AT2021axc (Lipunov et
al., GCN 29339) in the field of Fermi GRB 210120A (Fermi GBM Team, GCN
29334; Biltzinger et al. GCN 29335) with AZT-33IK telescope of Sayan
observatory (Mondy) starting on 2021-01-20 (UT) 20:57:41. The candidate
in optical afterglow (Lipunov et al., GCN 29339) is well detected in our
R-filter stacked image at R = 22.14 +/- 0.27 with 3 sigma upper limit of
the field for point-like source R=22.3. We confirm fading nature of the
transient and support it for afterglow candidate of GRB 210112A.
Preliminary photometry of the optical transient in the stacked image is
following
Date UT start t-T0 Filter Exp. OT Err. UL(3sigma)
(mid, days) (s)
2021-01-20 20:57:41 0.59510 R 30*120 22.14 0.27 22.3
The photometry is based on the nearby USNO-B1.0 stars
USNO-B1.0_id R2
1053-0195054 16.13
1053-0195003 18.57