EDP Sciences
Free access
Volume 381, Number 1, January I 2002
Page(s) 357 - 360
Section Physical and chemical processes
DOI http://dx.doi.org/10.1051/0004-6361:20011448

A&A 381, 357-360 (2002)
DOI: 10.1051/0004-6361:20011448

Magnetically accelerated particles in an anisotropic disk radiation field

Y. D. Xu

Physics Department, Shanghai Jiaotong University, 200030 Shanghai, PR China

(Received 20 July 2001 / Accepted 5 October 2001)

We consider the magnetic acceleration of charged particles in rotating magnetospheres of active galactic nuclei (AGNs). The accelerating particle loses its kinetic energy due to the inverse Compton scattering with the photons emitted from the disk. The disk radiation is anisotropic, so that the inverse Compton energy loss of the particle depends sensitively on the direction of motion of the particle. We find that the maximum Lorentz factor the accelerating electron can attain near the light cylinder is mainly determined by the direction of motion of the electron. In the cases of $L_{\rm disk}/L_{\rm Edd}\leq 10^{-2}$, the maximum Lorentz factor of a magnetically accelerated electron can be as high as a few thousand, if the electron is moving close to the normal direction to the disk. The maximum Lorentz factor becomes relatively low if $L_{\rm disk}/L_{\rm Edd}>10^{-2}$.

Key words: galaxies: active, nuclei -- acceleration of particles -- accretion disks

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