[vsnet-grb-info 27056] GRB 201223A: Nanshan/NEXT early optical afterglow detection

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  29159
SUBJECT: GRB 201223A: Nanshan/NEXT early optical afterglow detection
DATE:    20/12/23 18:58:50 GMT
FROM:    Dong Xu at NAOC/CAS  <dxu at nao.cas.cn>

Z.P. Zhu (NAOC, HUST), S.Y. Fu, X. Liu, D. Xu (NAOC), X. Gao (Urumqi 
No.1 Senior High School), J.Z. Liu (XAO) report:

We observed the field of GRB 201223A (Gropp et al., GCN 29158) using the 
NEXT-0.6m optical telescope located at Nanshan, Xinjiang, China. 
Observations automatically started at 18:01:14 UT on 2020-12-23, i.e., 
168 s after the BAT trigger. We obtained a series of 2x40s, 4x60s and 
12x90s frames in the Sloan r-filter, and observations are ongoing.

An uncatalogued decaying optical transient is detected at the Swift/UVOT 
position (Gropp et al., GCN 29158), which is thus concluded to be the 
optical afterglow of burst. The afterglow has r = 15.67 +/- 0.01 mag in 
our first image, calibrated with nearby PS1 stars.