TITLE:   GCN CIRCULAR
NUMBER:  21762
SUBJECT: LIGO/Virgo G299232: SVOM/2.16-m Optical Telescope Observations of Swift UVOT Transient
DATE:    17/08/30 09:25:32 GMT
FROM:    Chao Wu at NAOC  <wuchao.lamost@gmail.com>

X.M. Meng (NAOC), L.P. Xin (NAOC), S. Antier (LAL), C. Wu (NAOC),
N. Leroy (LAL), X.H. Han (NAOC), J.Y. Wei (NAOC), L. Huang (NAOC),
Y. Xu (NAOC), H.B. Cai (NAOC), J. Wang (NAOC), X.M. Lu (NAOC),
Y.L. Qiu (NAOC), J.S. Deng (NAOC), L. Cao (NAOC), S. Wang (NAOC),
L. Jia (NAOC), S.C. Zou (NAOC), S.F. Liu (NAOC), Q.C. Feng (NAOC),
H.L. Li (NAOC), D.W. Xu (NAOC), Y.J. Xiao (NAOC), W.L. Dong (NAOC),
Y.T. Zheng (NAOC), E.W.Liang (GXU), X.G.Wang (GXU), Y.G. Yang (HBNU),
B. Cordier (CEA), S.N. Zhang (NAOC), D. Dornic (CPPM), B.B. Wu (IHEP),
D. Turpin (IRAP), A. Klotz (IRAP), C.Lachaud (APC),
on behalf of the SVOM Gravitational Astronomy group report:

We made a follow-up observation for the reported source in
Emery et al. (GCN 21733)  at  2017-08-29 at  18:40:30  UTC,
with the BFOSC (Beijing Faint Object Spectrograph and Camera)
on the 2.16-m telescope at Xinglong Observatory, China.

No new source was detected in the stacked image with an total
exposure time of 2*600 sec, down to an upper limit of R~22
mag for 3 sigma, calibrated to the nearby SDSS DR9 r magnitudes.

Our results are consistent with the previous reports by
Tomasella et al. (GCN 21745); Pozanenko et al. (GCN 21754);
Copperwheat et al. (GCN 21755); Jonker et al. (GCN 21756);
Butler et al. (GCN 21757), Emery et al., (21758) that
the source was fading greatly,  compared to the brightness
reported in Emery et al. (GCN 21733) .

We thank the staff of 2.16m telescope in Xinglong observatory,
especially Huijuan Wang and Feng Xiao.