GCN Circular 29499
Subject
GRB 210204A (ZTF21aagwbjr/AT2021buv): continued CrAO and AbAO optical observations
Event
Date
2021-02-12T23:18:51Z (5 years ago)
From
Alexei Pozanenko at IKI, Moscow <apozanen@iki.rssi.ru>
S. Belkin (IKI), A. Pozanenko (IKI), V. Rumyantsev (CrAO), R. Ya.
Inasaridze (AbAO), N. Pankov (HSE) report on behalf of GRB IKI FuN:
We continued observation of the ZTF21aagwbjr/AT2021buv transient (Kool
et al., GCN 29405) at the redshift of 0.876 (Xu et al., GCN 29432) which
is an afterglow (Kennea et al., GCN 29413; Teja et al., GCN 29414;
Belkin et al., GCNs 29417, 29438; Rossi et al., GCN 29433; Gupta et
al., GCN 29490) of GRB 210204A (Fermi GBM team, GCN 29390; Li et al.,
GCN 29392; Hurley et al., GCN 29408; Waratkar et al., GCN 29410;
Frederiks et al., GCN 29415). Images in R-filter were taken with AS-32
telescope of Abastumani observatory (AbAO) and ZTSh 2.6m telescope of
CrAO observatory on 2021-02-09 and 2021-02-11.
Preliminary photometry of the afterglow in combined images is following
Date UT start t-T0 Filter Exp. OT Err. UL(3s) Telescope
(mid, days) (s)
2021-02-09 18:41:28 5.52572 R 25*120 21.09 0.08 22.6 ZTSh
2021-02-09 19:28:42 5.55610 R 43*60 21.4 0.2 22.5 AS-32
2021-02-11 18:18:20 7.50966 R 50*60 21.8 0.2 22.5 AS-32
2021-02-11 21:32:47 7.64817 R 30*120 21.6 0.3 21.8 ZTSh
The photometry is based on the nearby USNO-B1.0 stars
USNO-B1.0_id R2
1014-0149033 15.43
1014-0149115 17.00
A light curve can be found in
http://grb.rssi.ru/GRB210204A/GRB210204A_lc.png
Our photometry confirms suggested jet-break (Rossi et al. GCN 29433;
Gupta et al., GCN 29490).