Magnetization of jets in luminous blazars
  Luminosities of many powerful blazars are strongly dominated by $\gamma$-rays which most likely result from Comptonization of radiation produced outside a jet. This observation sets certain constraints on composition and energetics of the jet as well as the surrounding quasar environment. We study the dependence of a Compton dominance on a jet magnetization (the magnetic-to-matter energy flux) and on the location of the 'blazar zone'. Calculations are performed for two geometries of broad-emission-line and hot-dust regions: spherical and planar. The jet magnetization corresponding to the large observed Compton dominance is found to be $\sim 0.1 (\theta_{\rm j} \Gamma)^2$ for spherical geometries and $\sim 0.01 (\theta_{\rm j} \Gamma)^2$ for planar geometries, where $\theta_{\rm j}$ is the jet half-opening angle and $\Gamma$ is the jet Lorentz factor. This implies that jets in luminous blazars are matter dominated and that this domination is particularly strong for the flattened geometry of external radiation sources. 
Mateusz Janiak, Marek Sikora, Rafa{\l} Moderski
astro-ph.HE