GCN 44781: EP260602a: SVOM/VT optical candidate

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 EP260602a triggered by Einstein Probe (Li et al., GCN 44770). The observation started at 2026-06-02T15:37:33 UTC, 7.44 hours post trigger in the VT_B (400-650 nm) and VT_R (650-1000 nm) channels simultaneously.

An uncatalogued optical source was detected within WXT's error box (Li et al., GCN 44770) in both VT channels, compared to the Legacy Survey. The position is at R.A., Dec. = 240.862173, 50.563348  degrees, equivalent to:
R.A. (J2000) =  +16:03:26.92
Dec. (J2000) =  +50:33:48.05
with an uncertainty of 0.5 arcsec.

The following measurements are in the AB magnitude without correction for Galactic extinction:

Mid time | Band | Exposure Time | Brightness
9.49 h    VT_B     93*50 s        23.2  +/- 0.3  mag
9.51 h    VT_R     84*50 s        21.17 +/- 0.15 mag

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.