Kinematical Diagrams for Conical Relativistic Jets

Journal of astrophysics and astronomy

Pronoy Sircar2³  Samir Dhurde3²  Gopal-Krishna1¹ 

[1] National Centre for Radio Astrophysics, Tata Institute of Fundamental Research, Pune University Campus, Post Bag No. 3, Pune 411 007, India.$$;Inter-University Centre for Astronomy & Astrophysics, Pune University Campus, Post Bag No. 4, Pune 411 007, India.$$;Department of Physics, Indian Institute of Technology, Kanpur, India.$$

关键词: Blazars: general;    galaxies: active;    quasars;    jets;    nuclei;    radio continuum.;   

DOI  :  

学科分类：天文学(综合)

来源: Indian Academy of Sciences

【 摘 要 】

We present diagrams depicting the expected inter-dependences of two key kinematical parameters of radio knots in the parsec-scale jets of blazars, deduced from VLBI observations. The two parameters are the apparent speed (𝑣app = c𝛽app) and the effective Doppler boosting factor (𝛿eff) of the relativistically moving radio knot. A novel aspect of these analytical computations of 𝛽–𝛿 diagrams is that they are made for parsecscale jets having a conical shape, with modest opening angles (𝜔 up to 10°), in accord with the VLBI observations of the nuclei of the nearest radio galaxies. Another motivating factor is the recent finding that consideration of a conical geometry can have important implications for the interpretation of a variety of radio observations of blazar jets. In addition to uniform jet flows (i.e., those having a uniform bulk Lorentz factor, 𝛤), computational results are also presented for stratified jets where an ultra-relativistic central spine along the jet axis is surrounded by a slower moving sheath, possibly arising from a velocity shear.

【 授权许可】

Unknown