TITLE:   GCN CIRCULAR
NUMBER:  29166
SUBJECT: GRB 201223A: GWAC-F60A optical afterglow observations
DATE:    20/12/24 06:56:16 GMT
FROM:    Liping Xin at NAOC, SVOM  <xlp@nao.cas.cn>

L. P. Xin(NAOC),  L. H. Li(NAOC), X. H. Han(NAOC), J. Y. Wei(NAOC),  J. Wang(GXU),  
C. Wu(NAOC),  X. G. Wang(GXU), E. W. Liang (GXU), Y. L. Qiu(NAOC), and J. S. Deng(NAOC) report:

We began to observe GRB 201223A (Gropp et al., GCN #29158, 
Wood et al., GCN #29161) with Xinglong GWAC-F60A telescope, China, 
at 17:59:10.1 (UT), 23th. Dec. 2020, about 44 sec after the burst.

A series of  R, I, and B band images were obtained.
The optical afterglow reported by (Lipunov et al., GCN #29157; Gropp et
al., GCN #29158; Zhu et al., GCN #29159; Hu et al.，GCN #29160;
Hosokawa et al., GCN #29164; Filipp Dmitrievich Romanov GCN #29165)
was clear detected in our images. 

The brightness is fading from 15.0 mag to 18.8 mag  in R band
during about 100 sec to 10000 sec after the burst. 
 
The R-band brightness is calibrated to the USNO B1.0 catalog,
(RA=08:50:21.447, DEC=+71:12:12.80, J2000, R2=9.92)

More analysis are still continuing.

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