{
  "submitter": "SVOM_group <svomgroup@bao.ac.cn>",
  "eventType": [
    "GRB",
    "Optical Transient"
  ],
  "submittedHow": "web",
  "format": "text/markdown",
  "circularId": 45900,
  "subject": "GRB 261011A: SVOM/VT optical observation from VHF data",
  "createdOn": 1791733601783,
  "eventId": "GRB 261011A",
  "body": "C. Wu (NAOC), L. P. Xin, Y. L. Qiu (NAOC), J. T. Palmerio (CEA/Irfu), Massimiliano Lincetto (CPPM), Damien Dornic (CPPM), on behalf of the SVOM/VT team.\n\nAfter the trigger by SVOM/ECLAIRs (sb26101102) at 2026-10-11T13:49:04 UTC(T0), SVOM performed an automatic slew on the burst location ( Huang et al., GCN 45895).\n\nFrom a preliminary analysis of the 1-bit subimage and source list downloaded via the VHF network, the candidate reported by Swift/UVOT (Cenko et al., GCN 45896), Neill et al. (GCN 45897), Fu et al. (GCN 45898), Izzo et al. (GCN 45899) was clearly detected in VT VHF data. Details are presented below.\n\nThis candidate was detected in both VT_R and VT_B. Its  magnitudes are:\n\n| date-obs (UTC)      | mid-time   (t-T0) | exposure | VT_B mag(AB)  | VT_R mag(AB) | \n| ------------------- | ----------------- | -------- | ------------- | ------------ | \n| 2026-10-11T13:56:30 | 7.4  min          | 6x50 s   | 17.27 ± 0.10  | 16.260 ± 0.008 | \n| 2026-10-11T14:02:20 | 13.3 min          | 6x50 s   | 18.13 ± 0.10  | 17.17 ± 0.10  | \n\n\nMagnitudes were not corrected for Galactic reddening.\n\nThe Space-based multi-band astronomical Variable Objects Monitor (SVOM) is a China-France joint mission led by the Chinese National Space Administration (CNSA), French Space Agency (CNES), and the Chinese Academy of Sciences (CAS), which is dedicated to observing gamma-ray bursts and other transient phenomena in the energetic universe.\nSVOM/VT was jointly developed by Xi'an Institute of Optics and Precision Mechanics (XIOPM), CAS and National astronomical observatories (NAOC), CAS.\n"
}