GCN Circular 29523
Subject
GRB 210217A: NEXT early optical afterglow observations
Date
2021-02-18T00:20:00Z (3 years ago)
From
Dong Xu at NAOC/CAS <dxu@nao.cas.cn>
Z.P. Zhu (NAOC, HUST), S.Y. Fu, X. Liu, D. Xu (NAOC), X. Gao (Urumqi
No.1 Senior High School), J.Z. Liu (XAO) report:
We observed the field of GRB 210217A (Simpson et al., GCN 29521) using
the NEXT-0.6m optical telescope located at Nanshan, Xinjiang, China.
Observations automatically started at 23:27:06 UT on 2021-02-17, i.e.,
84 s after the BAT trigger. A series of 3x40 s, 4x60 s and 10x90 s
frames in the Sloan r-filter have been obtained, and observations are
ongoing.
An uncatalogued decaying optical transient is detected at the Swift/UVOT
position (Simpson et al., GCN 29521), which is thus concluded to be the
optical afterglow of burst. The afterglow has r = 18.6 +/- 0.2 mag in
our first image, calibrated with nearby PS1 stars.