General Relativistic Simulations of Early Jet Formation in a Rapidly Rotating Black Hole Magnetosphere

To investigate the formation mechanism of relativistic jets in active galactic nuclei and microquasars, we have developed a new general relativistic magnetohydrodynamic code in Kerr geometry. Here we report on the Ðrst numerical simulations of jet formation in a rapidly rotating (a \\ 0.95) Kerr black hole magnetosphere. We study cases in which the Keplerian accretion disk is both corotating and counter-rotating with respect to the black hole rotation, and investigate the Ðrst D50 light-crossing times. In the corotating disk case, our results are almost the same as those in Schwarzschild black hole cases: a gas pressureÈdriven jet is formed by a shock in the disk, and a weaker magnetically driven jet is also gener-ated outside the gas pressureÈdriven jet. On the other hand, in the counter-rotating disk case, a new powerful magnetically driven jet is formed inside the gas pressureÈdriven jet. The newly found magneti-cally driven jet in the latter case is accelerated by a strong magnetic Ðeld created by frame dragging in the ergosphere. Through this process, the magnetic Ðeld extracts the energy of the black hole rotation. Subject headings: accretion, accretion disks È black hole physics È galaxies: jets È magnetic Ðelds È methods: numerical È MHD È relativity 1.

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