AGN jet physics and apparent opening angles

Abstract

We present a new method to measure Γθj in flux-limited samples of active galactic nuclei (AGN) jets, where Γ is the bulk Lorentz factor and θj is the jet’s half-opening angle. The Γθj parameter is physically important for models of jet launching, and also determines the effectiveness of jet instabilities and magnetic reconnection. We measure Γθj by analyzing the observed distribution of apparent opening angles in very long baseline interferometry (VLBI) flux-limited samples of jets, given some prior knowledge of the active galactic nuclei (AGN) radio luminosity function. We then apply this method to the MOJAVE flux-limited sample of radio loud objects and find Γθj ≈ 0.1 ±0.03, which implies that AGN jets are subject to a variety of physical processes that require causal connection.