Doppler factors, Lorentz factors and viewing angles for quasars, BL Lacertae objects and radio galaxies
arXiv:0811.4278 · doi:10.1051/0004-6361:200811150
Abstract
We have calculated variability Doppler boosting factors, Lorentz factors, and viewing angles for a large sample of sources by using total flux density observations at 22 and 37 GHz and VLBI data. We decomposed the flux curves into exponential flares and determined the variability brightness temperatures of the fastest flares. By assuming the same intrinsic brightness temperature for each source, we calculated the Doppler boosting factors for 87 sources. In addition we used new apparent jet speed data to calculate the Lorentz factors and viewing angles for 67 sources. We find that all quasars in our sample are Doppler-boosted and that the Doppler boosting factors of BL Lacertae objects are lower than of quasars. The new Lorentz factors are about twice as high as in earlier studies, which is mainly due to higher apparent speeds in our analyses. The jets of BL Lacertae objects are slower than of quasars. There are some extreme sources with very high derived Lorentz factors of the order of a hundred. These high Lorentz factors could be real. It is also possible that the sources exhibit such rapid flares that the fast variations have remained undetected in monitoring programmes, or else the sources have a complicated jet structure that is not amenable to our simple analysis. Almost all the sources are seen in a small viewing angle of less than 20 degrees. Our results follow the predictions of basic unification schemes for AGN.
12 pages, 14 figures, Accepted for publication in A&A
References in corpus (12)
- Sub-milliarcsecond Imaging of Quasars and Active Galactic Nuclei III. Kinematics of Parsec-Scale Radio Jets
- Relativistic Beaming and the Intrinsic Properties of Extragalactic Radio Jets
- Multiwaveband Polarimetric Observations of 15 Active Galactic Nuclei at High Frequencies: Correlated Polarization Behavior
- Statistical analyses of long-term variability of AGN at high radio frequencies
- Long-term radio variability of AGN: flare characteristics
- Superluminal non-ballistic jet swing in the quasar NRAO 150 revealed by mm-VLBI
- A Multi-epoch VLBI Survey of the Kinematics of Caltech-Jodrell Bank Flat-Spectrum Sources, Part II: Analysis of the Kinematics
- Relativistic Jets in The Radio Reference Frame Image Database I: Apparent Speeds from the First Five Years of Data
- Wavelet analysis of a large sample of AGN at high radio frequencies
- MOJAVE: Monitoring of Jets in AGN with VLBA Experiments. IV. The Parent Luminosity Function of Radio-Loud Blazars
- The soft X-ray properties of AGN from the CJF sample; A correlation analysis between soft X-ray and VLBI properties
- The Lorentz factor distribution and luminosity function of relativistic jets in AGNs