T.H. Lu, X. Liu (NAOC), Z.P. Zhu (NAOC, HUST), S.Q. Jiang, S.Y. Fu, D.
Xu (NAOC), X. Gao (Urumqi No.1 Senior High School), J.Z. Liu (XAO) report:
We observed the field of GRB 221216A detected by Swift (Dichiara et al.,
GCN 33067) using the NEXT-0.6m telescope located at Nanshan, Xinjiang,
China. We obtained a series of frames in the Sloan r-band and z-band,
starting at 11:23:09 UT on 2022-12-16, i.e., 109s after the BAT trigger.
No optical source is detected in our stacked images at the XRT position
(Dichiara et al., GCN 33067), with upper limits as follows:
T_mid-T0 (min) Filter Upper limit(3-sigma)
14.26 r >17.5
14.90 z >16.5
calibrated with the nearby SkyMapper field and not corrected for