The Prospects of Finding Tidal Disruption Events with 2.5-Metre Wide-Field Survey Telescope (WFST) Based on Mock Observations

Abstract

Optical time-domain survey has been the dominant means of hunting for rare tidal disruption events (TDEs) in the past decade and remarkably advanced the TDE study. Particularly, the Zwicky Transient Facility (ZTF) has opened the era of population studies and the upcoming Large Synoptic Survey Telescope (LSST) at the Vera Rubin Observatory (VRO) is believed to further revolutionize the field soon. Here we present the prospects of finding TDEs with another powerful survey to be performed by 2.5metre Wide-Field Survey Telescope (WFST). The WFST, located in western China, will be the most advanced facility dedicated to optical time-domain surveys in the northern hemisphere once commissioning. We choose to assess its TDE detectability on the basis of mock observations, which is hitherto closest to reality by taking into consideration of site conditions, telescope parameters, survey strategy and transient searching pipeline. Our mock observations on 440 deg 2 field (CosmoDC2 catalogue) show that 29 ± 6 TDEs can be robustly found per year if observed at 𝑢, 𝑔, 𝑟, 𝑖 bands with 30-second exposure every 10 days, in which a discovery is defined as ≥10 epochal detections in at least two filters. If the WFST survey is fully optimized for discovering TDE, we would expect to identify 392 ± 74 of TDEs every year, with the redshift up to 𝑧 ∼ 0.8, which poses a huge challenge to follow-up resources.