GENERAL-RELATIVISTIC MAGNETOHYDRODYNAMIC SIMULATIONS OF JETS FROM BLACK-HOLE ACCRETION DISKS - 2-COMPONENT JETS DRIVEN BY NONSTEADY ACCRETION OF MAGNETIZED DISKS

The radio observations have revealed the compelling evidence of the ex istence of relativistic jets not only from active galactic nuclei but also from ''microquasars'' in our Galaxy. In the cores of these object s, 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 deve loped the general relativistic magnetohydrodynamic code. Using the cod e, we present a model of these relativistic jets, in which magnetic fi elds penetrating the accretion disk around a black hole play a fundame ntal role of inducing nonsteady accretion and ejection of plasmas. Acc ording to our simulations, a jet is ejected from a close vicinity to a black hole (inside 3r(s), where r(s) is the Schwarzschild radius) at a maximum speed of similar to 90% of the light velocity (i.e., a Loren tz factor of similar to 2). The jet has a two-layered shell structure consisting of a fast gas pressure-driven jet in the inner part and a s low magnetically driven jet in the outer part, both of which are colli mated by the global poloidal magnetic field penetrating the disk. The former jet is a result of a strong pressure increase due to shock form ation in the disk through fast accretion flow (''advection-dominated d isk'') inside 3r(s), which has never been seen in the nonrelativistic calculations.