Accretion disk luminosity for black holes surrounded by dark matter with
  anisotropic pressure
  We investigate the luminosity of the accretion disk for a static black hole
surrounded by dark matter with anisotropic pressure. We calculate all basic
orbital parameters of test particles in the accretion disk, such as angular
velocity, angular momentum, energy and radius of the innermost circular stable
orbit as functions of the dark matter density, radial pressure and anisotropic
parameter, which establishes the relationship between the radial and tangential
pressures. We show that the presence of dark matter with anisotropic pressure
makes a noticeable difference in the geometry around a Schwarzschild black
hole, affecting the radiative flux, differential luminosity and spectral
luminosity of the accretion disk.
