[vsnet-grb-info 27597] GRB 210323A: Nanshan/NEXT optical upper limit

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  29700
SUBJECT: GRB 210323A: Nanshan/NEXT optical upper limit
DATE:    21/03/23 23:09:33 GMT
FROM:    Dong Xu at NAOC/CAS  <dxu at 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 210323A (Gropp et al., GCN 29699) using the 
NEXT-0.6m telescope located at Nanshan, Xinjiang, China. Observations 
automatically started at 22:03:49 UT on 2021-03-23 (i.e., 91 s after the 
BAT trigger), and 3x40 s, 4x60 s and 12x90 s frames were obtained in the 
Sloan r-filter.

No optical source is detected in our stacked image at the XRT position 
(Gropp et al., GCN 29699), down to a limiting magnitude of r~20.4, 
calibrated with nearby PanSTARRS stars.