{
  "body": "L.P. Xin, H.L. Li, Y. L. Qiu, C. Wu, Z.H. Yao, Y. Xu, P.P. Zhang, J. Wang, Y.N. Ma, X.H. Han, H.B. Cai, J.Y. Wei, W.J. Xie (NAOC), Y.H. Cheng (SWIFAR, YNU), B.T. Wang (YNAO, CAS), J. T. Palmerio (CEA)\nreport on behalf of the SVOM/VT team:\n\nSVOM performed a Target of Opportunity observation of GRB 250329B (Xie et al., GCN 39925), starting at 2025-03-29T15:00:16 UT, ~2.85 hours after the SVOM/Eclairs trigger, in the VT_B (400nm-650nm) and VT_R (650nm-1000nm) channels simultaneously.\n\nNo any source was detected in the stacked images within the errorbox of the X-ray Swift/XRT [source #1]( https://www.swift.ac.uk/SVOM/SVOM_FIELD00008/) .\n\nThe 3 sigma limits in VT_R is 23.1 mag (AB) at the middle time of 4.0 hours after the burst.\n\nThis result is consistent with the reports (Xin et al., GCN 39926, Chen et al., GCN 39929).\n\nDeeper or redder follow-ups are encouraged to investigate the nature of the burst.\n\nThe 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.",
  "createdOn": 1743275629053,
  "subject": "GRB 250329B:  SVOM/VT optical upper limit",
  "submittedHow": "web",
  "eventId": "GRB 250329B",
  "bibcode": "2025GCN.39931....1X",
  "format": "text/plain",
  "circularId": 39931,
  "submitter": "Liping Xin at NAOC, SVOM <xlp@nao.cas.cn>"
}