2013MNRAS.431.1914G

We have recently proposed a new simplified scenario where blazars are classified as flat spectrum radio quasars (FSRQs) or BL Lacs according to the prescriptions of unified schemes, and to a varying combination of Doppler-boosted radiation from the jet, emission from the accretion disc, the broad line region and light from the host galaxy. Here we extend our approach, previously applied to radio and X-ray surveys, to the γ-ray band and, through detailed Monte Carlo simulations, compare our predictions to Fermi-Large Area Telescope (LAT) survey data. Our simulations are in remarkable agreement with the overall observational results, including the percentages of BL Lacs and FSRQs, the fraction of redshift-less objects and the redshift, synchrotron peak and γ-ray spectral index distributions. The strength and large scatter of the oft-debated observed γ-ray-radio flux density correlation are also reproduced. In addition, we predict that almost 3/4 of Fermi-LAT BL Lacs, and basically all of those without redshift determination, are actually FSRQs with their emission lines swamped by the non-thermal continuum and as such should be considered. Finally, several of the currently unassociated high Galactic latitude Fermi sources are expected to be radio-faint blazars displaying a pure elliptical galaxy optical spectrum.