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.KeywordsBlack HoleAccretion DiskActive Galactic NucleusPoloidal FieldNonrelativistic CaseThese keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.

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