GCN Circular 22804
Subject
GRB 180618A: Xinglong-2.16m optical upper limit
Date
2018-06-20T13:02:02Z (6 years ago)
From
Dong Xu at NAOC/CAS <dxu@nao.cas.cn>
Z.P. Zhu, D. Xu, J.B. Zhang (NAOC), X. Zhang, J.H. Liu (XAO), Z.B. Dai
(YNAO) report:
We observed the field of GRB 180618A (LaPorte et al., GCN 22790) using
the 2.16-m telescope located at Xinglong, Hebei, China, equipped with
the BFOSC camera. We obtained 6x600s R-band frames, starting at 12:43:22
UT on 2018-06-19, i.e., 1.50 days after the BAT trigger.
The previously detected optical afterglow of the GRB (e.g., LaPorte et
al., GCN 22790; Guidorzi et al., GCN 22792; Tyurina et al., GCN 22797)
was not present in our stacked image, down to a limiting magnitude of
R~21.4 mag, calibrated with the SDSS field.