Total Flux Density Variations in Extragalactic Radio Sources. 3. Doppler Boosting211 Factors, Lorentz Factors and Viewing Angles for Active Galactic Nuclei

摘要

We have calculated Doppler boosting factors D(var) for a sample of active211u001egalactic nuclei (AGN) using total flux density variation monitoring data at 22 211u001eGHz and 37 GHz. We compare our Doppler factors with other results and conclude 211u001ethat even if the average D(var) for a class of sources is very similar to all 211u001eothers, the variability Doppler factors for individual objects are more accurate 211u001eand reliable. An important application of precise Doppler factors is presented, 211u001enamely calculating the Lorentz factors Gamma and the viewing angles theta of 211u001erelativistic outflows in AGN. We find that high polarization quasars are the most 211u001eDoppler boosted objects while low polarization quasars and BL Lac objects are 211u001eless boosted. The two groups of quasars show different characteristics due to a 211u001edifferent combination of the Lorentz factor and the viewing angle rather than 211u001eeither different Gamma or theta alone.