Departament d'Astronomia i Astrofísica
Universitat de València

    Parallel, grid-adaptive simulations of relativistic jets

Zakaria Meliani

Katholieke Universiteit Leuven, Bèlgica

Seminari del departament d'Astronomia i AstrofĂ­sica

Dijous 18 novembre 2010



The two types of Fanaroff-Riley radio loud galaxies, FRI and FRII, exhibit strong jets but with different properties. These differences may be associated to the central engine and/or the external medium. In this seminar I will present two models. I will start to discuss the dichotomy FRI/FRII accroding to the properties of the central engine, In this model we linked the AGN classification FRI and FRII to the transverse stratification of the jet. Indeed, theoretical arguments support this transverse stratification of jets with two components induced by intrinsic features of the central engine (accretion disk + black hole). We demonstrate that two-component jets with a relatively low kinetic energy flux contribution from the outer disk-jet are subject to the development of a relativistically enhanced, rotation-induced Rayleigh-Taylor type non-axisymmetric instability. This instability induces strong mixing between both components, decelerating the inner jet and leading to overall jet decollimation. In the second part, I will present the model that we proposed to explain HYbrid MOrphology Radio Sources (HYMORS), thereby invoking density discontinuities and variation in the initial open angle of jet. We explore how one-sided jet deceleration and a transition to FR I type can occur in HYMORS, which start as FR II (and remain so on the other side). The result of these work is that the FRII/FRI transition, can be associated to the central engine that induces transverse stratification of the jet and/or can be associated to the central engine (jet open angle) + external medium (density jump)