On Post-starburst Galaxies Dominating Tidal Disruption Events

A starburst induced by a galaxy merger may create a relatively thin central stellar disk at radius ≤100 pc. We calculate the rate of tidal disruption events (TDEs) by the inspiraling secondary supermassive black hole (SMBH) through the disk. With a small enough stellar velocity dispersion ($\sigma /{v}_{c}\leqslant 0.1$) in the disk, it is shown that 105–106 TDEs of solar-type main-sequence stars per post-starburst galaxy (PSB) can be produced to explain their dominance in producing observed TDEs. Although the time it takes to bring the secondary SMBH to the disk apparently varies in the range of ∼0.1–1 Gyr since the starburst, depending on its landing location and subsequently due to dynamical friction with stars exterior to the central stellar disk in question, the vast majority of TDEs by the secondary SMBH in any individual PSB occur within a time span shorter than ∼30 Myr. Five unique testable predictions of this model are suggested.