Study Of The Bardeen-Petterson Effect In The Magnetized Disc Around AGN

Tilted orbits about a rotating compact object experience a torque due to the general relativistic Lense-Thirring effect (Lense-Thirring 1918), which causes the plane of the orbit to precess. For a fluid accretion disk, the differential precession with radius causes stresses and dissipation. Bardeen-Petterson concluded in 1975 that a tilted disk around Kerr black hole suffer a gravitomagnetic torque that tends to twist and warp the disk. The torque produced by the nonspherically symmetric gravitational field of the hole. The gas flows of the accretion disk are forced to produce Lense-Thirring precession align with the spin of the black hole and the precession is . is the angular momentum of the black hole. The precession varies with the radius causes the tilted accretion disk to warp into the equatorial plane of the rotating hole. From then, it is called Bardeen-Petterson effect.Active Galactic Nuclei (AGN) is a important research of astrophysics, it can reflect the acts of the in the active state. Active Galactic Nuclei is composed of the massive black hole and the accretion disk. The jet is formed in the internal region in the accretion disk, along its normal direction. Because the accreted matter moves with a tilt angle to the rotating axis of the black hole, the accretion disk become distorted by the Lense-Thirring effect and the viscous in vertical plane. So the spatial orientation of the jet varies with the axis of the internal region of the disk. The direction of the jet remains unchanged over yr and this explanation of a natural site is that the internal region of the disc is well perpendicular to the black hole's spin axis (Bardeen-Petterson effect on the region's internal calibration).The important role of magnetic field in the process of accretion: Lynden-Bell (1969) and Shakura - Sunyaev (1973) proposed that the magnetic field play an important role in the angular momentum transfer ([9], [40]), Lightman & Eardley (1975) and Field & Rogers (1993) analyzed the magnetic effect's contribution of angular momentum transport with the thin accretion disk models ([58], [59]). Pariev et al then offered the magnetized accretion disk model in 2003 and in the model: the magnetic pressure of the small scale magnetic fields dominant over the thermal and radiation pressure. Considering the important role of magnetic field in the process of accretion, this paper analyzes the Bardeen-Petterson effect of the magnetized accretion disc of AGN.In the calculation process, this paper uses magnetized SSD models simulating the accretion disc of AGN and analyzes the Bardeen-Petterson effect in the internal region of the disc under the condition of axisymmetric accretion. Results from the analysis are found: The magnitude of Tilt |W| monotonically increasing with radius r, at the same time increasing with the central black hole mass-M and the magnetic field B.Finally, this paper analyzes the condition under which the Bardeen-Petterson effect can appear within the internal region of the accretion disk around Kerr black hole and analyzes the scope for the application of the Bardeen-Petterson effect.