On the unified view of extragalactic sources based on their broadband emission properties

Abstract

Our understanding of the unification of jetted AGNs has advanced greatly as the size of extragalactic sources increased. In the present paper, based on the large sample of radio sources, we compiled 680 blazars (279 FSRQs and 401 BL Lacs) from the 3FGL sample and 64 Seyfert galaxies (3 Narrow-line, 34 and 27 regular Seyfert 1 and Seyfert 2 respectively) from the INTEGRAL survey to statistically test the relationship between Seyfert galaxies and the blazar samples of FSRQs and BL Lacs. We compute the synchrotron (SS), Compton (CS) and inverse Compton (IC) continuous spectra from the low energy components of radio to X-ray, radio to gamma-ray and the high energy component of X-ray to gamma-ray bands, respectively. Results show from the distributions of the continuous spectra that Seyfert galaxies form the tail of the distributions, suggestive of similar underlying history and evolution. A two-sample Kolmogorov-Smirnov test (K.S test) of the continuous spectra showed that Seyfert galaxies differ from BL Lacs and FSRQs in the low energy components of the spectra, while there is no clear difference between them in the high energy component, which implies that high energy emissions in Seyfert galaxies, BL Lacs and FSRQs may be as a result of the same emission mechanism. There is a regular sequence of the distributions on SS/CS and IC/CS planes in each individual subsample. Linear regression analyses of our sample yield significant positive correlations (r greater than 0.60) between SS/CS and IC/CS data. This upturns into an anti-correlation (r greater than -0.60) in IC/SS data. These results are not only consistent with unified scheme for blazars but also show that Seyfert galaxies can be unified with the classical radio-loud AGNs counterparts.