[vsnet-grb-info 26743] GRB 201103B (ZTF20acozryr/AT2020yxz): Nanshan/NEXT-0.6m optical observations

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  28846
SUBJECT: GRB 201103B (ZTF20acozryr/AT2020yxz): Nanshan/NEXT-0.6m optical observations
DATE:    20/11/06 02:36:07 GMT
FROM:    Dong Xu at NAOC/CAS  <dxu at nao.cas.cn>

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

We observed the optical transient, ZTF20acozryr/AT2020yxz, an likely 
orphan GRB optical afterglow when discovered by ZTF (Coughlin et al., 
GCN 28841) and later confirmed by the IPN localisation as the optical 
afterglow of GRB 201103B (Svinkin et al., GCN 28844), using the 
NEXT-0.6m optical telescope located at Nanshan, Xinjiang, China. 
Observations started at 17:33:06 UT on 2020-11-05 and a series of 120s 
exposures were obtained in the Sloan r-filter.

Considering the IPN trigger time, 18:06:47 UT on 2020-11-03, as the 
onset of the burst, preliminary photometry results are as follows:

T_mid_obs (UT) T_mid_grb(day)  Mag   MagErr
2020-11-05T17:43:35    1.984      20.5    0.3
2020-11-05T18:31:28    2.017      20.8    0.2

calibrated with nearby PS1 stars.

Compared with the ZTF photometry, such a decay is consistent with that 
of a conventional GRB optical afterglow.