2024RAA....24k5006W

In spite of the importance of studying the cosmic generation of heavy elements through the r-process, the detection of a kilonova resulting from the merger of a neutron star binary is still a challenging task. In this paper, we show that the Visible Telescope (VT) onboard the ongoing SVOM space mission is powerful for identifying kilonova candidates associated with short gamma-ray bursts up to a distance of 600 Mpc. A significant color variation, turning blue and then turning red, is revealed by calculating the light curves in both red and blue channels of VT by a linear combination of an afterglow and an associated kilonova. The maximum color variation is as high as ∼0.5-1 mag, which is far larger than the small photometry error of ∼0.2 mag of VT for a point source with a brightness of 23 mag. Up to a distance of 600 Mpc, ∼1-2 kilonova candidates per year are predicted to be identified by VT.