Orientation and Beaming Effects in active galactic nuclei: Implication for radio galaxy - Blazar Evolution

The orientation and evolution based on unified scheme for jetted extragalactic radio sources posits that BL Lacertae objects (BLs), flat-spectrum radio quasars (FSRQs) and normal radio galaxies (RGs) represent increasingly misaligned populations of active galactic nuclei (AGNs). Using compiled radio, X-ray and γ-ray data of 397 blazars and 110 RGs from the Fermi Large Area Telescope (Fermi-LAT) catalogue, we computed the viewing angles, γ-ray core-dominance parameter and γ-ray emission components in order to study the consequences of orientation and relativistic beaming effects on γ-ray properties of RGs, BLs and FSRQs. Our results show continuous distributions of core-dominance parameters (X-ray, RX and γ-ray, Rγ) from RGs at low values, largest viewing angles to FSRQs at high values and BLs subsets with the least values. The difference on the plane is significantly larger for FSRQs and BLs than for RGs, indicating an evolutionary link between them. A two-sample Wilcoxon rank-sum and Kolmogorov-Smirnov tests carried out on our data suggest that the probabilities of the distribution of RX and Rγ of RGs and blazar types to come from the same parent distribution are pWRS ∼ 0 and pK−S 0.60) between log Rr - log RX for the combined sample types. Furthermore, a significant anti-correlation (r ∼ -0.80) exists in the log Rγ - log Lγ,un plot which is indicative of evolutionary sequence via relativistic beaming model. These results imply that the evolutionary track of jetted AGNs is RGs - BLs FSRQs