Kinematics of AGN and Quasar Jets

TL;DR

This paper reviews VLBA observations of AGN and quasar jets, discussing their kinematics, acceleration, and potential for future multi-wavelength studies with upcoming space missions.

Contribution

It provides a comprehensive overview of jet kinematics, acceleration zones, and the implications for relativistic beaming models, highlighting future observational opportunities.

Findings

Jet Lorentz factors extend up to about 30.

Evidence of acceleration up to 1 kpc downstream.

Some jets show curved or precessing trajectories.

Abstract

The major multi-epoch VLBA programs are described and discussed in terms of relativistic beaming models. Broadly speaking the observed kinematics are consistent with models having a parent population which is only mildly relativistic but with Lorentz factors extending up to about 30. While the collimation and acceleration appears to mainly occur close to the central engine, there is evidence of accelerations up to 1 kpc downstream. Generally the motion appears to be linear, but in some sources the motion follows a curved trajectory. In other sources, successive features appear to be ejected in different directions possibly the result of a precessing nozzle. The launch of GLAST in 2008 will offer new opportunities to study the relation between radio and gamma-ray activity, and possibly to locate the source of the gamma-ray emission. VSOP-2 will give enhanced resolution and will facilitate the study of the two-dimensional structure of relativistic jets, while RadioAstron will provide unprecedented resolution to study the fine scale structure of the jet base.