TITLE:   GCN CIRCULAR
NUMBER:  26904
SUBJECT: GRB 200127A: Nanshan-0.6m optical upper limit
DATE:    20/01/28 02:37:47 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 200127A (Moss et al., GCN 26895) using the 
NEXT-0.6m telescope located at Nanshan, Xinjiang, China. Observations 
started at 23:26:58 UT on 2020-01-27 (i.e., 8.71 h after the BAT 
trigger), and 7x300 s Sloan r-band frames were obtained.

No optical afterglow is detected within the enhanced Swift-XRT error 
circle (Evans et al., GCN 26902) in our stacked image, down to a 
limiting magnitude of r ~ 20.5, calibrated with the nearby PanSTARRS field.