GCN Circular 30669
Subject
GRB 210820A: Nanshan/NEXT optical upper limit
Date
2021-08-21T04:01:10Z (3 years ago)
From
Dong Xu at NAOC/CAS <dxu@nao.cas.cn>
S.Y. Fu (NAOC), Z.P. Zhu (NAOC,HUST), X. Liu, D. Xu (NAOC), X. Gao
(Urumqi No.1 Senior High School), J.Z. Liu (XAO) report:
We observed the field of GRB 210820A (Beardmore et al., GCN 30664) using
the NEXT-0.6m telescope located at Nanshan, Xinjiang, China. We obtained
10x200 s frames in the Sloan r-band, starting at 21:17:58 UT on
2021-08-20, i.e., 3.67 hr after the BAT trigger.
No optical source is detected in our stacked image at the Swift/UVOT
position (Beardmore et al., GCN 30664), down to a limiting magnitude of
r~21.3, calibrated with the nearby PanSTARRS field.