GCN Circular 44732
Subject
EP250526a: SVOM/VT optical upper limits
Event
Date
2026-05-29T02:52:08Z (17 hours ago)
From
Huali Li at at NAOC, SVOM <lhl@nao.cas.cn>
Via
Web form
J. R. Xu, H. L. Li, C. Wu, Y. L. Qiu, L. P. Xin, 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, L. Lan, J. S. Deng, J. Y. Wei (NAOC) and J. Palmerio (CEA/Irfu) report on behalf of the SVOM/VT team.
SVOM/VT performed ToO observations to the field of EP260526a triggered by Einstein Probe (Yang et al., GCN 44712). The observation started at 2026-05-27T05:44:54 UTC, 20.022 hours post trigger in the VT_B (400-650 nm) and VT_R (650-1000 nm) channels simultaneously.
No uncatalogued sources were detected in stacked images within the error box of EP-FXT (Yang et al, GCN 44721) and EP-WXT (Yang et al, GCN 44712), compared to the Legacy Survey. The 3 sigma limit magnitudes are derived as follows:
Mid time | Band | Exposure Time | 3 sigma upper limit
21.53 h VT_B 57*50 s > 23.5 mag
21.53 h VT_R 57*50 s > 23.3 mag
Our non-detection is consistent with the observations from COLIBRÍ (Becerra et al., GCN 44710) and LCO (van Hoof et al., GCN 44713).
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.