Estimates of Doppler Factors, Outflow Angles, and Bulk Lorentz Factors for a Sample of Compact Radio Sources

Abstract

Two key results are presented in this paper. First, equipartition Doppler factors have been estimated for a sample of 105 sources with previously estimated inverse Compton Doppler factors. The different categories of active galactic nuclei (AGN) have different ranges and typical values of the Doppler factor; lobe dominated AGN tend to have low Doppler factors, core-dominated quasars tend to have large Doppler factors, and BL Lacertae objects span the full range of Doppler factors. These results support the "orientation unified model" for different categories of AGN. The second key result comes from combining equipartition Doppler factors and apparent velocities from superluminal motion studies. There are 43 sources for which apparent speeds and equipartition Doppler factors are available. The bulk Lorentz factor and outflow angle are estimated for each of these 43 sources. Again, typical parameter values for different categories of AGN are quite interesting, and generally agree with expectations based on the orientation unified model.