Relativistic two-component jet evolutions in 2D and 3D

Abstract

Observations of astrophysical jets and theoretical arguments suggest a transverse stratification with two components induced by intrinsic features of the central engine (accretion disk + black hole). We study two-component jet dynamics for an inner fast low density jet, surrounded by a slower, denser, extended jet. We investigate for the first time this two-component jet evolution with very high resolution in 2.5D and 3D. We demonstrate that two-component jets with high kinetic energy flux contribution from the inner jet are subject to the development of a relativistically enhanced, rotation-induced Rayleigh-Taylor type instability. This instability induces strong mixing between both components, decelerating the inner jet and leading to overall jet decollimation. The 3D simulation confirms the dominance of the non-axisymmetric character of this novel explanation for sudden jet deceleration. We note that it can explain the radio source dichotomy as a direct consequence of the efficiency of the central engine in launching the inner jet component. We argue that the FRII/FRI transition, interpreted in our two-component jet scenario, occurs when the relative kinetic energy flux of the inner to the outer jet exceeds a critical ratio.