[vsnet-grb-info 28196] GRB 210619B: AbAO optical observations

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  30299
SUBJECT: GRB 210619B: AbAO optical observations
DATE:    21/06/22 12:13:52 GMT
FROM:    Alexei Pozanenko at IKI, Moscow  <apozanen at iki.rssi.ru>

S. Belkin (IKI), A. Pozanenko (IKI), R. Ya. Inasaridze (AbAO), V. R. 
Ayvazian (AbAO),  G. V. Kapanadze (AbAO), N. Pankov (HSE, IKI) report on 
behalf of IKI GRB FuN:

We observed the field of GRB 210619B (D'Avanzo et al., GCN 30261; Zhao 
et al., GCN 30264; Axelsson et al., GCN 30270; Svinkin et al., GCN 
30276; Levin et al., GCN 30283; Kawakubo et al., GCN 30284) with AS-32 
telescope of Abastumani observatory (AbAO) in R-filter on June, 21. The 
optical afterglow (Lipunov et al., GCN 30259; D'Avanzo et al., GCNs 
30261, 30288; Lipunov et al., GCN 30262; Jelinek et al., GCNs 30263, 
30281; Kong, GCN 30265; Pellegrin et al., GCN 30268, Perley et al., GCN 
30271; Zheng and Filippenko, GCN 30273; Blazek et al., GCN 30274; Kann 
et al., GCN 30275; Xin et al., GCN 30277; Shrestha et al., GCN 30280; 
Kumar et al., GCN 30286; Moskvitin et al., GCN 30291;  Romanov, GCN 
30292; Hu et al., GCN 30293; Zhu et al., GCN 30294) is detected in the 
stacked image. Preliminary photometry of the afterglow is following

Date       UT start   t-T0    Filter Exp.    OT     Err.  UL(3sigma)
                        (mid, days)    (s)

2021-06-21 23:16:31   1.98931  R     55*60   20.6  0.3  20.6

The photometry is based on the nearby stars:
USNO-B1.0 R2
1238-0493928 15.08
1238-0494511 15.67