Black Hole : Extraction of Rotational Energy by a Magnetic Field and Relativistic Jet Formation

Abstract

Relatrvistic jets have now been discovered in several different classes of astrophysical objects, including active galactic nuclei, microquasars, and gamma-ray bursts. Since such extremely high speed jets are never ejected from any ordmary object, it is believed that the objects with extremely strong gravity-black holes - exist and are responsible for the jet ejection. The energy of such jet may be supphed from the energy of black hole itself. However, the black hole swallows every matenal, information, and energy, even light around it. How does the black hole radiate the power? Recent numerical experiments show the rotational energy of the black hole can be extracted by the large-scale magnetic field naturally and Alfven wave is induced to propagate outward along the magnetic field lines. In this article, we outline the unusual phenomena around the rotating black hole.