On the Lorentz factor of superluminal sources

We investigate the properties of features seen within superluminal sources often referred to as components. Our result indicates a fairly strong correlation of r ~ 0.5 for quasars, r ~ 0.4 for galaxies and r ~ 0.7 for BL Lac objects in our sample between component sizes and distances from the stationary core. The assumption of free adiabatic expanding plasma enables us to constrain the Lorentz factor for superluminal sources. Our estimated Lorentz factor of γ ~ 9-13 for quasars, γ ~ 7-11 for galaxies and γ ~ 4-9 for BL Lac objects indicates that BL Lacs have the lowest range of Lorentz factors.