[vsnet-grb-info 25900] GRB 200613A: CrAO optical observations

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  28000
SUBJECT: GRB 200613A: CrAO optical observations
DATE:    20/06/20 11:51:17 GMT
FROM:    Alexei Pozanenko at IKI, Moscow  <apozanen at iki.rssi.ru>

S. Belkin (IKI), A. Pozanenko (IKI),  V. Rumyantsev (CrAO),  A. Volnova 
(IKI), E. Mazaeva (IKI) report on behalf of larger GRB follow-up 
collaboration:

We observed the  GRB 200613A (Fermi GBM team, GCN 27926; Bissaldi et 
al., GCN 27930; Ohno et al., GCN 27931; Yamaoka Ohno et al., GCN 27964)  
with ZTSH 2.6m telescope of CrAO observatory starting on 2020-06-19 (UT) 
18:58:23.  The optical afterglow (e.g., Kann et al., GCN 27935; 
Pozanenko et al., GCN 27937; Izzo et al., GCN 27939; Zhu et al., GCN 
27943; Marshall, GCN 27944; Liu et al., GCN 27949; Belkin et al., GCN 
27958) is detected in a stacked image. Preliminary photometry of the 
afterglow is following

Date       UT start  t-T0    Filter Exp.   OT    Err. UL
                     (mid, days)     (s)
2020-06-19 18:58:23  6.58142 R      29*120 21.06 0.09 23.6

The photometry is based on nearby SDSS star
SDSS-DR12_id      R(Lupton)
J101207.75+454443.4 17.877

A light curve of the afterglow of  GRB 200613A can be found in 
http://grb.rssi.ru/GRB200613A/GRB200613A_lc_v2.png