TITLE:   GCN CIRCULAR
NUMBER:  26883
SUBJECT: GRB 200125A: Nanshan-0.6m optical upper limit
DATE:    20/01/26 02:55:33 GMT
FROM:    Dong Xu at NAOC/CAS  <dxu@nao.cas.cn>

X. Liu, D. Xu, Z.P. Zhu, B.Y. Yu, Y. Ma (NAOC), X. Gao (Urumqi No.1 
Senior High School) report:

We observed the field of GRB 200125A (Lien et al., GCN 26876) using the 
NEXT-0.6m telescope located at Nanshan, Xinjiang, China. Observations 
started at 23:06:52 UT on 2020-01-25 (i.e., 11.59 h after the BAT 
trigger), and 10x300 s Sloan r-band frames were obtained.

No optical afterglow is detected within the enhanced Swift-XRT error 
circle (Beardmore et al., GCN Circ. 26878) in our stacked image, down to 
a limiting magnitude of r ~ 21.0, calibrated with the nearby PanSTARRS 
field.