TITLE: GCN CIRCULAR NUMBER: 20404 SUBJECT: LIGO/Virgo G268556: GWAC_F60B (60cm) follow-up two events of EWE001 and EWE002 DATE: 17/01/09 12:50:04 GMT FROM: Chao Wu at NAOC J.Y. Wei (NAOC), L.P. Xin (NAOC)， X.M. Meng (NAOC)， X.H. Han (NAOC), N.Leroy (LAL), S. Antier (LAL), C. WU (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), S. Basa (LAM), B.B. Wu (IHEP), Jean-Luc Atteia (IRAP), D. Götz (CEA), C. Lachaud (APC) on behalf of the SVOM Gravitational Astronomy group report: We took images on the location of two events of EWE001 and EWE002 (Liu et al LVC Circ. 20382) with our GWAC_F60B (60cm) telescope, which is dedicated to identify transient candidates found by GWAC (a part of ground instrument of SVOM mission) at Xinglong Observatory, China. Observation were obtained in R band for 15 X 900s expoures during 16:49:29 and 22:02:03 (UTC) on Juanary 8, 2017. The two events(objects) are corresponding to known objects in USNO-B1.0 catalog. ----------------------------------------------------------------------- EWE001: mag_R = 16.98 mag_R2(in USNO) = 15.35 EWE002: mag_R=16.77 mag_R2(in USNO) = 16.57 ------------------------------------------------------------------------ The photometric uncertainty is ~ 5%. The comparison star is object with mag_R2 =16.17 (09:13:19.611 61:05:44.13 J2000).