GCN Circular 22274
Subject
GRB 171222A: Nanshan-1m optical afterglow detection
Event
Date
2017-12-23T14:00:59Z (8 years ago)
From
Dong Xu at NAOC/CAS <dxu@nao.cas.cn>
X. Zhang, P. Zong, J.H. Liu (XAO), H.X. Feng, Z.P. Zhu, D. Xu (NAOC),
H.B. Niu, J.Z. Liu, A. Esamdin, L. Ma, Y. Zhang (XAO) report on behalf
of a larger collaboration:
We observed the field of GRB 171222A (Racusin et al., GCN 22265) using
the 1m telescope located at Nanshan, Xinjiang, China. We obtained 6x300s
R-band frames, starting at 18:14:36 UT on 2017-12-22, i.e., 1.83 hr
after the BAT trigger.
An uncatalogued and fading optical transient (OT) is detected at the XRT
position (Osborne et al., GCN 22266) as well as the NOT position (Perley
et al., GCN 22269) in our images. Preliminary photometry results are as
follows:
Tmid-T0 Exposure Filter Mag(R) MagErr(R)
(hr) (s)
1.87 1x300 R 20.86 0.21
2.68 3x300 R 21.47 0.22
7.87 2x300 R 21.72 0.22
Photometry is calibrated with nearby USNO-B1.0 stars (R2 magnitudes),
and errors are only statistical values. We thus conclude that this OT is
the optical afterglow of GRB 171222A.