TITLE: GCN CIRCULAR NUMBER: 40535 SUBJECT: The EP-WXT trigger 01709176612: SVOM/VT optical observations DATE: 25/05/23 12:16:31 GMT FROM: Liping Xin at NAOC, SVOM <xlp@nao.cas.cn> L. P. Xin, Y. L. Qiu, H. L. Li, C. Wu, Z. H. Yao, Y. N. Ma, X. H. Han, J. Wang, H. Q. Cheng (NAO, CAS), Q. C. Shui (IHEP, CAS), Y. J. Song, Z. X. Ling (NAO, CAS) report on behalf of the SVOM and EP mission teams: SVOM performed a Target of Opportunity observation of he EP-WXT trigger 01709176612 (Song et al., GCN 40523, Chen et al.,, GCN 40534). SVOM/VT began observing the field at 2025-05-22T06:57:11 UTC, 60.32 min after the trigger in the VT_B (400nm-650nm) and VT_R (650nm-1000nm) channels simultaneously. The exposure time for each frame is 70 seconds. The WISEA J122501.45-521614.6 identified as the counterpart of the trigger (Evans et al., GCN 40528, Chen et al., GCN 40534) was saturated in all VT_R band images, but showed a fading for roughly 0.5 mag from saturated to about 13.3 mag (AB) in VT_B band during our 2 orbit observations. The optical variation in VT_B is consistent with the stellar flare (Chen et al., GCN 40534). The Space Variable Objects Monitor (SVOM) is a China-France joint mission led by the Chinese National Space Administration (CNSA, China), National Center for Space Studies (CNES, France) and the Chinese Academy of Sciences (CAS, China), which is dedicated to observing gamma-ray bursts and other transient phenomena in the energetic universe. VT was jointly developed by Xi'an Institute of Optics and Precision Mechanics (XIOPM), CAS and National astronomical observatories (NAOC),CAS. View this GCN Circular online at https://gcn.nasa.gov/circulars/40535. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0LW...