On the Unification of Low Luminosity Active Galactic Nuclei

Abstract

We have used the distributions of observed radio properties of a subset of AGNs called low luminosity AGNs (LLAGNs) to investigate the relationship between radio-selected BL Lacs (RBLs and XBLs) and Fanaroff-Riley Type I radio galaxies (FRI) in accordance with the unified scheme. Analysis of the core and extended luminosity show that RBLs are more core dominated than XBLs which are also more core dominated than FRI radio galaxies. Distributions of core dominance parameter (R) give Rm ≈ 42.41 ± 10.77, 5.08 ± 1.57, and 0.34 ± 0.0024 for RBLs, XBLs, and FRI, corresponding to mean viewing angles (ϕm) in the range ϕ ≈ 70 − 170, 130 − 240 and 200 − 280 respectively. Regression analysis of the three samples shows that the core to extended luminosity plot (LC − LE) yields a strong correlation of r ≈ 0.67±0.52, 0.85±0.46, and 0.79±0.61 for FRI, RBLs and XBLs at 95% confidence level. Similarly, regression analysis of R and ϕ for FRI, RBLs, and XBLs all yield a strong anti-correlation of r ≈ −0.98±0.02, −0.64±40.52, and 0.75±4.45. These results are consistent with BL Lac/FRI unification and suggest that relativistic beaming of the core and extended emissions is significant in low luminosity AGNs and thus a strong support for the unified scheme.