{
  "subject": "EP260610a: SVOM/VT optical upper limits",
  "submittedHow": "web",
  "submitter": "Huali Li at at NAOC, SVOM <lhl@nao.cas.cn>",
  "format": "text/plain",
  "bibcode": "2026GCN.44896....1L",
  "body": "H. L. Li, L. P. Xin, C. Wu, Y. L. Qiu, J. R. Xu,, Y. N. Ma, Z. H. Yao, X. H. Han, J. Wang, Y. Xu, P. P. Zhang, W. J. Xie, Y. J. Xiao, H. B. Cai, J. S. Deng, J. Y. Wei (NAOC), J. T. Palmerio (CEA/Irfu) report on behalf of the SVOM/VT team.\n\nSVOM/VT performed a ToO observation of the field of EP260610a triggered by Einstein Probe (Wu et al., GCN 44889). The observation started at 2026-06-10T05:47:51 UTC, i.e., about 1.18 hours post trigger in the VT_B (400-650 nm) and VT_R (650-1000 nm) channels simultaneously.\n\nNo uncatalogued optical source was detected at the FXT source position (Wu et al., GCN 44889) in our stacked images, compared to the Legacy Survey. The 3-sigma upper limits are:\n\nMid_time    Band    Exposure Time   Magnitude (AB) \n2.27 h      VT_B       83*50 s       > 23.8 mag\n2.27 h      VT_R       84*50 s       > 23.4 mag\n\nThe magnitudes are in the AB system and are not corrected for Galactic extinction.\nOur non-detection is consistent with the observation from COLIBRÍ (Postigo et al., GCN 44890).\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": 1781102401361,
  "eventId": "EP260610a",
  "circularId": 44896
}