On the Extended Blazar Sequence for γ-Ray Emitting Active Galactic Nuclei

Abstract

In this paper, we use the distributions of observed γ-ray properties, as well as orientation parameters of a sample of Fermi-LAT AGNs to investigate the hypothesis that γ-NLS1 objects are beamed sources with γ-ray emitting axes inclined at close angles to the line of sight. Based on these parameters we investigate the relationship between γ-NLS1s and other subclasses of γ[-ray emitting jetted AGNs. Results show that γ-NLS1s are more highly beamed than both FSRQs and BL Lacs with mean value of core-dominance parameter R_g ~ 9507. γ-NLS1s and jetted Seyfert galaxies are continuous in distribution of the orientation parameter with average cone angles Φ_m ~ 8° and 44° respectively. Furthermore, the spectral energy distribution of γ-NLS1 is comparable to those of FSRQs and BL Lacs suggestive that γ-NLS1s and blazars form a continuous spectral sequence. There is a significant anti-correlation (r ~ -0.9) between the γ-ray dominance D_g and γ-ray luminosity. There is a strong dependence of D_g on redshift (r ~ -0.7) suggestive that D_g is more sensitive to environmental factors than intrinsic γ-ray luminosity. The results suggest that γ-NLS1s are highly beamed γ-ray sources whose de-beamed counterparts can be found among Seyfert galaxy populations.