Years Delayed X-ray Afterglows of TDEs Originated from Wind-Torus
  Interactions
  Tidal disruption events (TDEs) occurred in active galactic nuclei (AGNs) are
a special class of sources with outstanding scientific significance. TDEs can
generate ultrafast winds, which should almost inevitably collide with the
preexisting AGN dusty tori. We perform analytical calculations and simulations
on the wind-torus interactions and find such a process can generate
considerable X-ray afterglow radiation several years or decades later after the
TDE outburst. This provides a new origin for the years delayed X-rays in TDEs.
The X-ray luminosity can reach 10^{41-42} erg/s, and the light curve
characteristics depend on the parameters of winds and tori. We apply the model
to two TDE candidates, and provide lower limits on the masses of the disrupted
stars, as well as rigorous constraints on the gas densities of tori. Our
results suggest that the observations of the time delay, spectral shape,
luminosity and the light curve of the X-ray afterglow can be used to constrain
the physical parameters of both TDE winds and tori, including the wind
velocity, wind density and torus density.
