GCN Circular 31213
Subject
GRB 211211A: Nanshan/NEXT optical observations
Event
Date
2021-12-12T11:42:12Z (4 years ago)
From
Dong Xu at NAOC/CAS <dxu@nao.cas.cn>
S.Q. Jiang (NAOC), 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 211211A detected by Fermi (Fermi GBM team,
GCN 31201) and Swift (D'Ai et al., GCN 31202) using the NEXT-0.6m
optical telescope located at Nanshan, Xinjiang, China. Observations
started at 23:01:09 UT on 2021-12-11, i.e., 9.85 hr after the BAT
trigger, and 10x200 s frames in the Sloan r-filter as well as 12x200 s
frames in the Sloan z-filter were obtained.
The optical afterglow candidate of the GRB reported by KAIT (Zheng &
Filippenko, GCN 31203), consistent with the enhanced Swift-XRT position
(Beardmore et al., GCN 31205), is detected in our stacked r- and z-band
images. Preliminary photometry is as follows:
T_mid-T0 (hr) Mag MagErr Filter
10.34 20.29 0.07 r
10.68 19.9 0.3 z
both calibrated with nearby PS1 stars.
We note that the NEXT's r-band magnitude is comparable to that of KAIT
in the clear band, although the time interval of the two observations is
~10 hr.