[vsnet-grb-info 20713] GRB 180620A: Xinglong-2.16m optical observations

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  22811
SUBJECT: GRB 180620A: Xinglong-2.16m optical observations
DATE:    18/06/20 19:20:31 GMT
FROM:    Dong Xu at NAOC/CAS  <dxu at nao.cas.cn>

Z.P. Zhu, D. Xu, J.B. Zhang (NAOC), X. Zhang, J.H. Liu (XAO) report

We observed the field of GRB 180620A (Evans et al., GCN 22790) using the 
2.16-m telescope located at Xinglong, Hebei, China, equipped with the 
BFOSC camera. We obtained 3x600s R-band frames, starting at 12:39:01 UT 
on 2018-06-20, i.e., 4.068 hrs after the BAT trigger.

The GRB's optical afterglow (Evans et al., GCN 22790; Butler et al., GCN 
22799; Elenin et al., GCN 22800; Tyurina et al., GCN 22801; Guidorzi et 
al., GCN 22803) is clearly detected in each frame. Preliminary 
photometry shows the afterglow has decayed to m(R)~20.0, calibrated with 
nearby USNO B1 stars.

We acknowledge the excellent support from the Xinglong staff, 
particularly Xiao Feng and Huijuan Wang, in obtaining these observations.