Ratio of the Co-Moving Luminosity in the Jet to the Unbeamed Luminosity of Blazars

Abstract

In a relativistic beaming model, the emissions are composed of two components, namely, the boosted and the unbeamed ones. But how much is from each part is unclear. However, in the radio band, the de-beamed radio luminosity \(\left( {L_{jet}^{db}} \right)\) in the jet has been assumed to be proportional to the unbeamed luminosity (Lub) in the co-moving frame, i.e., \(f = \frac{{L_{jet}^{db}}} {{{L_{ub}}}}\). The value of the ratio, f is not easy to determine, but it is associated with the core-dominance (R), bulk velocity (β), and viewing angle (θ) . In this paper, used the beaming model, the Doppler factors, and superluminal motion (SM) velocity, the ratio, f is determined for 41 sources. Results show that f mainly satisfies, log f = −3.5 to 2 for the whole sample. If we consider BL Lacertae objects (BLs) and flat spectral radio quasars (FSRQs) separately, we found that the averaged value is log f = −1.59±0.19 for FSRQs and log f = 0.11±0.49 for BLs. This results can perhaps explain why there are emission lines and strong beaming effect in FSRQs and there is no (or very weak) emission lines in BLs.KeywordsAGNSuperluminal MotionRelativistic Beaming Model