The History of Tidal Disruption Events in Galactic Nuclei
  The tidal disruption of a star by a massive black hole (MBH) is thought to
produce a transient luminous event. Such tidal disruption events (TDEs) may
play an important role in the detection and characterization of MBHs and probe
the properties and dynamics of their nuclear stellar clusters (NSCs) hosts.
Previous studies estimated the recent rates of TDEs in the local universe.
However, the long-term evolution of the rates throughout the history of the
universe has been hardly explored. Here we consider the TDE history, using
evolutionary models for the evolution of galactic nuclei. We use a 1D
Fokker-Planck approach to explore the evolution of MBH-hosting NSCs, and obtain
the disruption rates of stars during their evolution. We complement these with
an analysis of TDEs history based on N-body simulation data, and find them to
be comparable. We consider NSCs that are built-up from close-in star-formation
(SF) or from SF/clusters-dispersal far-out, a few pc from the MBH. We also
explore cases where primordial NSCs exist and later evolve through additional
star-formation/cluster-dispersal processes. We study the dependence of the TDE
history on the type of galaxy, as well as the dependence on the MBH mass. These
provide several scenarios, with a continuous increase of the TDE rates over
time for cases of far-out SF and a more complex behavior for the close-in SF
cases. Finally, we integrate the TDE histories of the various scenarios to
provide a total TDE history of the universe, which can be potentially probed
with future large surveys (e.g. LSST).
