TITLE: GCN CIRCULAR NUMBER: 37074 SUBJECT: GRB 240805B: JinShan optical afterglow detection DATE: 24/08/06 15:03:47 GMT FROM: Dong Xu at NAOC/CAS dxu@nao.cas.cn
Z.P. Zhu, X. Liu, J. An, S.Y. Fu, S.Q. Jiang, L.B. He, D. Xu (NAOC), J.Z. Liu (XAO) report on behalf of a large collaboration:
We reported JinShan optical upper limits (GCN 37050) at the Swift/XRT position of GRB 240805B (Williams et al., GCN 37043).
Later on, the Enhanced Swift-XRT position was available (Goad et al., GCN 37053), which has a quite positional shift compared to the early position (Williams et al., GCN 37043).
Checking the Enhanced Swift-XRT position in the JinShan images, we find the optical afterglow (e.g., Moskvitin et al., GCN 37055; Du et al., GCN 37062) is detected in the r-/i-/z- bands. Thus, the updated preliminary results are as follows:
Telescope Tmid-T0/hr Filter Exptime Mag(AB) MagErr 50D 1.683 g 20x180s >21.5 - 100C 0.582 r 5x200s 20.03 0.06 100C 0.868 i 5x200s 18.79 0.02 100C 1.318 z 7x300s 18.79 0.02
We acknowledge the excellent support from S.W. Luo, M.M. Yang, Z.K. Feng, Q.C. Zhao and L.F. Huo for enabling these observations.
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