A Radio Flare Associated with the Nuclear Transient Erasst J234403-352640: an Outflow Launched by a Potential Tidal Disruption Event

We present an extensive radio monitoring campaign of the nuclear transienteRASSt J234403-352640 with the Australia Telescope Compact Array, one of themost X-ray luminous TDE candidates discovered by the SRG/eROSITA all-skysurvey. The observations reveal a radio flare lasting more than 1000 d,coincident with the X-ray, UV, optical, and infra-red flare of this transientevent. Through modelling of the 10 epochs of radio spectral observationsobtained, we find that the radio emission is well-described by an expandingsynchrotron emitting region, consisting of a single ejection of materiallaunched coincident with the optical flare. We conclude that the radio flareproperties of eRASSt J234403-352640 are consistent with the population ofradio-emitting outflows launched by non-relativistic tidal disruption events,and that the flare is likely due to an outflow launched by a tidal disruptionevent (but could also be a due to a new AGN accretion event) in a previouslyturned-off AGN.