General Relativistic Magnetohydrodynamic Simulations of Jets from Black Hole Accretion Disks: Two-Component Jets Driven by Nonsteady Accretion of Magnetized Disks

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Abstract
The radio observations have revealed the compelling evidence of the existence of relativistic jets not only from active galactic nuclei but also from "microquasars" in our Galaxy. In the cores of these objects, it is believed that a black hole exists and that violent phenomena occur in the black hole magnetosphere, forming the relativistic jets. To simulate the jet formation in the magnetosphere, we have newly developed the general relativistic magnetohydrodynamic code. Using the code, we present a model of these relativistic jets, in which magnetic fields penetrating the accretion disk around a black hole play a fundamental role of inducing nonsteady accretion and ejection of plasmas. According to our simulations, a jet is ejected from a close vicinity to a black hole (inside 3rS, where rS is the Schwarzschild radius) at a maximum speed of ~90% of the light velocity (i.e., a Lorentz factor of ~2). The jet has a two-layered shell structure consisting of a fast gas pressure-driven jet in the inner part and a slow magnetically driven jet in the outer part, both of which are collimated by the global poloidal magnetic field penetrating the disk. The former jet is a result of a strong pressure increase due to shock formation in the disk through fast accretion flow ("advection-dominated disk") inside 3rS, which has never been seen in the nonrelativistic calculations.