VLASS tidal disruption events with optical flares I: the sample and a comparison to optically-selected TDEs

TL;DR

This study uses VLASS to identify six radio-selected TDEs with optical counterparts, revealing trends in host galaxy and optical properties that differ from optically-selected TDEs, and constrains their occurrence rate.

Contribution

First sample of radio-selected TDEs with optical counterparts, providing insights into their properties and potential selection biases compared to optically-selected TDEs.

Findings

Radio-selected TDEs have faint, cool optical flares.

Host galaxies of radio-selected TDEs tend to have low SMBH masses.

Radio-selected TDEs exhibit more energetic radio emission regions.

Abstract

In this work, we use the Jansky VLA Sky Survey (VLASS) to compile the first sample of six radio-selected tidal disruption events (TDEs) with transient optical counterparts. While we still lack the statistics to do detailed population studies of radio-selected TDEs, we use these events to suggest trends in host galaxy and optical light curve properties that may correlate with the presence of radio emission, and hence can inform optically-selected TDE radio follow-up campaigns. We find that radio-selected TDEs tend to have faint and cool optical flares, as well as host galaxies with low SMBH masses. Our radio-selected TDEs also tend to have more energetic, larger radio emitting regions than radio-detected, optically-selected TDEs. We consider possible explanations for these trends, including by invoking super-Eddington accretion and enhanced circumnuclear media. Finally, we constrain the radio-emitting TDE rate to be $\gtrsim 10$ Gpc$^{-3}$ yr$^{-1}$.