GCN Circular 29252
Subject
GRB 210104A: Nanshan/NEXT optical powerlaw decay
Date
2021-01-05T03:04:27Z (4 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 210104A (Troja et al., GCN 29233) using the
NEXT-0.6m optical telescope located at Nanshan, Xinjiang, China.
Observations started at 11:59:19 UT (i.e., 0.538 hr post-burst) on
2021-01-04 and ended at 22:34:07 UT (i.e., 11.11 hr post-burst) on
2021-01-04, and a series of 120 s, 200 s, 300 s Sloan r-band frames were
obtained.
Preliminary analysis of the data shows that afterglow is decaying as
F_rband ~ t^(-\alpha), where \alpha = 0.73 since the very beginning of
our observations.
If the afterglow continues to decay in this way, it would be of r ~ 20.3
mag at 1 day post-burst, and still bright enough for optical spectroscopy.