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.