Population of gamma-ray sources in The Third Fermi LAT catalog

The Third Fermi LAT catalog (3FGL) is the most important astronomical catalog of gamma-ray sources, a long-lasting reference for high-energy astrophysics. As of today, perhaps surprisingly, more than a third of 3FGL sources lack a classification, not being identified nor even associated to sources at other wavelengths. Therefore finding a tool that could aid in the identification would be very helpful. To this purpose, we selected data from 3FGL, processed and analyzed them for the various categories of objects. In a first exploratory part of our investigation, we built histograms for galactic latitudes, photon fluxes, energy fluxex, spectral indices, variability indices and redshift of our samples, and tried interpreting the distributions. Secondly, we also built broad-band color-color diagrams that we used as diagnostic tools to verify the nature of already associated objects, and particularly to test those of the unidentified sources.