  Motivated by the fact that the universe is dominated by dark matter and dark
energy, we consider rotating black holes surrounded by perfect fluid dark
matter and study the accretion process in thin disk around such black holes.
Here, we are interested in how the presence of dark matter affects the
properties of the electromagnetic radiation emitted from a thin accretion disk.
For this purpose, we use the Novikov-Thorne model and obtain the
electromagnetic spectrum of an accretion disk around a rotating black hole in
perfect fluid dark matter and compare with the general relativistic case. The
results indicate that for small values of dark matter parameter we considered
here, the size of the innermost stable circular orbits would decrease and thus
the electromagnetic spectrum of the accretion disk increases. Therefore, disks
in the presence of perfect fluid dark matter are hotter and more luminous than
in general relativity. Finally, we construct thin accretion disk images around
these black holes using the numerical ray-tracing technique. We show that the
inclination angle has a remarkable effect on the images, while the effect of
dark matter parameter is small.
