GCN Circular 30504
Subject
GRB 210722A: Nanshan/NEXT further optical observations
Event
Date
2021-07-25T07:56:29Z (4 years ago)
From
Dong Xu at NAOC/CAS <dxu@nao.cas.cn>
S.Y. Fu (NAOC), Z.P. Zhu (NAOC, HUST), X. Liu, D. Xu (NAOC), X. Gao
(Urumqi No.1 Senior High School), J.Z. Liu (XAO) report:
We continued to observe the field of GRB 210722A (D'Avanzo et al., GCN
30475) using the NEXT-0.6m telescope located at Nanshan, Xinjiang,
China. We obtained 15x200 s frames in the Sloan r-band, starting at
20:41:20 UT on 2021-07-24, i.e., 1.99 days after the burst.
The previously reported optical afterglow (e.g., D'Avanzo et al., GCN
30475; Zhu et al., GCN 30476) is not detected in our stacked image, down
to a limiting magnitude of r~21.0, calibrated with the nearby PanSTARRS
field.