Catching jetted tidal disruption events early in millimetre

Abstract

Relativistic jets can form from at least some tidal disruption events (TDEs) of (sub-)stellar objects around supermassive black holes. We detect the millimetre (MM) emission of IGR J12580+0134 - the nearest TDE known in the galaxy NGC 4845 at the distance of only 17 Mpc, based on Planck all-sky survey data. The data show significant flux jumps after the event, followed by substantial declines, in all six high-frequency Planck bands from 100 to 857 GHz. We further show that the evolution of the MM flux densities is well consistent with our model prediction from an off-axis jet, as was initially suggested from radio and X-ray observations. This detection represents the second TDE with MM detections; the other is Sw J1644+57, an on-axis jetted TDE at redshift of 0.35. Using the on- and off-axis jet models developed for these two TDEs as templates, we estimate the detection potential of similar events with the Large Millimeter Telescope (LMT) and the Atacama Large Millimeter/ submillimeter Array (ALMA). Assuming an exposure of 1 h, we find that the LMT (ALMA) can detect jetted TDEs up to redshifts z ∼ 1 (2), for a typical disrupted star mass of ∼1 M⊙. The detection rates of on- and off-axis TDEs can be as high as ∼0.6 (13) and 10 (220) yr-1, respectively, for the LMT (ALMA). We briefly discuss how such observations, together with follow-up radio monitoring, may lead to major advances in understanding the jetted TDEs themselves and the ambient environment of the circumnuclear medium.