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

TL;DR

This study evaluates the potential of the 2.5-metre Wide-Field Survey Telescope (WFST) in detecting tidal disruption events (TDEs) through mock observations, indicating it could significantly enhance TDE discovery rates in the northern hemisphere.

Contribution

It provides a realistic assessment of WFST's TDE detection capabilities based on detailed mock observations considering site conditions and survey strategies.

Findings

WFST could detect approximately 29 TDEs annually with current survey parameters.

Optimized WFST survey could identify around 392 TDEs per year up to redshift 0.8.

Detection relies on multiple epochal observations across several filters.

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 2.5-metre 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 $29\pm6$ 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 $\geq$10 epochal detections in at least two filters. If the WFST survey is fully optimized for discovering TDE, we would expect to identify $392\pm74$ of TDEs every year, with the redshift up to $z\sim0.8$, which poses a huge challenge to follow-up resources.