GCN Circular 30476
Subject
GRB 210722A: Nanshan/NEXT optical afterglow observations
Date
2021-07-22T21:58:22Z (3 years ago)
From
Dong Xu at NAOC/CAS <dxu@nao.cas.cn>
Z.P. Zhu (NAOC, HUST), S.Y. Fu, D. Xu, X. Liu (NAOC), X. Gao (Urumqi
No.1 Senior High School), J.Z. Liu (XAO) report:
We observed the field of GRB 210722A (D'Avanzo et al., GCN 30475) using
the NEXT-0.6m telescope located at Nanshan, Xinjiang, China. We obtained
a series of 40 s, 60 s, 90 s frames in the Sloan r-band, starting at
20:56:45 UT on 2021-07-22, i.e., 123 s after the BAT trigger, among
which part of the frames are useless due to the cloudy weather.
An uncatalogued optical transient is detected at the Swift/UVOT position
(D'Avanzo et al., GCN 30475) with varying brightness, and thus confirms
it as the optical afterglow of the burst. Preliminary analysis of the
beginning photometry is as follows:
Tmid-T0(sec) Mag MagErr
143 14.33 0.01
361 13.94 0.01
452 14.01 0.01
All magnitudes are calibrated with the nearby PS1 field.