Title:
Tidal Stream Circularization by Supermassive Schwarzschild Black Holes

Abstract:
A star that wanders within the tidal radius of a supermassive black hole (SMBH) 
will be torn apart by the tidal field of the SMBH. Approximately 50% of the tidal debris 
will become gravitationally bound to the black hole and evolve into a tidal stream. 
This tidal stream must dissipate substantial energy if it is to form 
a quasi-circular accretion disk at the circularization radius from 
which gas can be accreted onto the SMBH, powering a luminous tidal 
disruption event (TDE). This energy dissipation may occur in an inelastic collision 
when the stream intersects with itself. The timing and efficiency of energy dissipation 
at this collision point depends crucially on the kinematics of the tidal stream 
including relativistic apsidal precession. We develop a semi-analytic model 
to estimate the energy dissipated at the collision point as a function of SMBH mass 
and stellar orbital angular momentum and the resulting delays to disk circularization.