Years Delayed Gamma-ray and Radio Afterglows Originated from TDE Wind-Torus Interactions

Tidal disruption events (TDEs) that occur in active galactic nuclei (AGNs) with dusty tori are a special class of sources. TDEs can generate ultrafast and large opening-angle winds, which will almost inevitably collide with the preexisting AGN dusty tori a few years later after the TDE outburst. The wind-torus interactions will drive two kinds of shocks: the bow shocks at the windward side of the torus clouds, and the cloud shocks inside the torus clouds. In a previous work, we proved that the shocked clouds will give rise to considerable X-ray emissions which can reach $10^{41-42}~{\rm erg s^{-1}})$ (so called years delayed \emph{X-ray afterglows}). In this work, we focus on the radiations of high energy particles accelerated at both shocks. Benefitting from the strong radiation field at the inner edge of the torus, the inverse Compton scattering of AGN photons by relativistic electrons at bow shocks dominates the overall gamma-ray radiation. The gamma-ray luminosity can reach an outstanding level of $10^{41}~{\rm erg s^{-1}}) (L_{\rm kin}/10^{45}{\rm erg s^{-1}})$, where $L_{\rm kin}$ is the kinetic luminosity of TDE wind. The radio emission is dominated by relativistic electrons at bow shocks via synchrotron radiation, and can reach $10^{35-37}~{\rm erg s^{-1}}) (L_{\rm kin}/10^{45}{\rm erg s^{-1}})$ at 1-10 GHz if the magnetic field is 100-1000 mGauss. The neutrino production rate is dominated by pp collisions inside the torus cloud, which is in the order of $10^{40}~{\rm erg s^{-1}})$. Our scenario provides a prediction of the years delayed afterglows in radio/X-ray/gamma-ray band for TDE and reveals their connections, Moreover, it suggests a novel method for exploring the clouds around the central black hole and the power of TDE winds.