Numerical Simulation of Relativistic Jet Formation in Black Hole Magnetosphere

Abstract

The radio jets ejected from active galactic nuclei (AGNs) sometimes show proper motions with apparent velocity exceeding the speed of light (e.g., Hughes, 1991). This phenomenon, called superluminal motion, is explained as relativistic jets propagating in a direction almost toward us, and has been thought to be ejected from the close vicinity of hypothetical supermassive black holes powering AGNs (Rees, 1966). Recently, similar superluminal motion has been discovered in some compact radio/X-ray sources (i.e., “microquasars”) in our Galaxy, such as GRS 1915+105 (Mirabel & Rodriguez, 1994), which are considered to be black hole candidates. In spite of the vast differences in luminosity and the sizes of microquasar in our Galaxy (e.g., GRS 1915+105, whose luminosity is 3 × 10³⁸ erg/s and size < 10⁶ cm) and those of AGNs (luminosity ~ 10⁴⁷ erg/s and the size < 10¹⁴ cm), both objects are believed to be powered by gravitational energy released during the accretion of plasmas onto black holes. The mass of black holes, M _BH, is estimated to be < 10 solar mass for microquasars, and ~ 10⁸ solar mass for AGNs. If we normalize the length by the Schwarzschild radius r _S = 2GM _BH/c ², both objects become similar and thus can be understood in a unified model as in the following.