Diffuse $\gamma$-ray emission from misaligned active galactic nuclei
  We calculate the diffuse $\gamma$-ray emission due to the population of
misaligned AGN (MAGN) unresolved by the Large Area Telescope (LAT) on the {\it
Fermi} Gamma-ray Space Telescope ({\it Fermi}). A correlation between the
$\gamma$-ray luminosity and the radio-core luminosity is established and
demonstrated to be physical by statistical tests, as well as compatible with
upper limits based on {\it Fermi}-LAT data for a large sample of radio-loud
MAGN. We constrain the derived $\gamma$-ray luminosity function by means of the
source count distribution of the MAGN detected by the {\it Fermi}-LAT. We
finally estimate the diffuse $\gamma$-ray flux due to the whole MAGN population
which ranges from 10% up to nearly the entire measured Isotropic Gamma-Ray
Background (IGRB). We evaluate also the room left to galactic DM at high
latitudes ($>10^\circ$), by taking into account the results on the MAGN
together with the other significant galactic and extragalactic $\gamma$-rays
emitting sources.
