Relativistic Beaming and Orientation Effects in BL Lacertae Objects

Journal of astrophysics and astronomy

A. E. Chukwude²  A. A. Ubachukwu²  F. C. Odo1¹ 

[1] National Centre for Energy Research and Development, University of Nigeria, Nsukka, Nigeria$$;Department of Physics & Astronomy, University of Nigeria, Nsukka, Nigeria$$

关键词: Galaxies: BL Lacertae objects: general.;   

DOI  :  

学科分类：天文学(综合)

来源: Indian Academy of Sciences

【 摘 要 】

We use the correlation between the core-to-lobe radio luminosity ratio (𝑅) and the linear size (𝐷) of a sample of BL Lacertae objects to investigate the relativistic beaming and radio source orientation paradigm for high peaked and low-peaked BL Lacs (X-ray and radio selected BL Lacs respectively) and to constrain relativistic beaming model for this extreme class of active galactic nuclei. We show that the 𝑅 - 𝐷 distributions of the BL Lac populations contradict blazar orientation sequence, with the X-ray selected BL Lacs (XBLs) being more consistent with the beaming and orientation model. On the premise that Fanaroff-Riley Type I radio galaxies are the unbeamed parent population of these objects, we derive the bulk Lorentz factor of the jets, 𝛾 ∼ 7-20 corresponding to a critical cone angle for optimum boosting, 𝜙c of ∼ 1° - 4°, while on average, these objects are inclined at 5° - 12° to the line-of-sight. The implications of these results for the blazar unification sequence are discussed.

【 授权许可】

Unknown