Dark matter velocity dispersion effects on CMB and matter power spectra
  Effects of velocity dispersion of dark matter particles on the CMB TT power
spectrum and on the matter linear power spectrum are investigated using a
modified CAMB code. Cold dark matter originated from thermal equilibrium
processes does not produce appreciable effects but this is not the case if
particles have a non-thermal origin. A cut-off in the matter power spectrum at
small scales, similar to that produced by warm dark matter or that produced in
the late forming dark matter scenario, appears as a consequence of velocity
dispersion effects, which act as a pressure perturbation.
