Tidal disruption rate of stars by supermassive black holes obtained by
  direct N-body simulations
  The disruption rate of stars by supermassive black holes (SMBHs) is
calculated numerically with a modified version of Aarseth's NBODY6 code. The
initial stellar distribution around the SMBH follows a S\'{e}rsic n=4 profile
representing bulges and early type galaxies. In order to infer relaxation
driven effects and to increase the statistical significance, a very large set
of N-body integrations with different particle numbers N, ranging from 10^{3}
to 0.5 \cdot 10^{6} particles, is performed. Three different black hole capture
radii are taken into account, enabling us to scale these results to a broad
range of astrophysical systems with relaxation times shorter than one Hubble
time, i.e. for SMBHs up to M_bh \approx 10^{7} M_sun. The computed number of
disrupted stars are driven by diffusion in angular momentum space into the loss
cone of the black hole and the rate scales with the total number of particles
as dN/dt \propto N^{b}, where b is as large as 0.83. This is significantly
steeper than the expected scaling dN/dt \propto ln(N) derived from simplest
energy relaxation arguments. Only a relatively modest dependence of the tidal
disruption rate on the mass of the SMBH is found and we discuss our results in
the context of the M_bh/sigma relation. The number of disrupted stars
contribute a significant part to the mass growth of black holes in the lower
mass range as long as a significant part of the stellar mass becomes swallowed
by the SMBH. This also bears direct consequences for the search and existence
of IMBHs in globular clusters. For SMBHs similar to the galactic center black
hole SgrA*, a tidal disruption rate of 55 \pm 27 events per Myr is deduced.
Finally relaxation driven stellar feeding can not account for the masses of
massive black holes M_bh \geq 10^{7} M_sun. (abridged)
