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P. C. Fragile, G. J. Mathews, J. R. Wilson (University of Notre Dame)
The Bardeen-Petterson effect around a rapidly rotating compact object causes the inner portion of a tilted accretion disk to warp into the equitorial plane of the rotating body. The resulting accretion flow is separated into two distinct regions - an inner aligned accretion disk and an outer tilted accretion disk. The transition between these two regions occurs at a characteristic radius that depends on the mass and angular momentum of the central object. We propose that accreting material passing from the outer disk to the inner disk may generate quasi-periodic brightness oscillations such as have been observed in a number of X-ray binaries. We show that the predictions of this model are consistent with some of the moderate frequency (1-300 Hz) QPOs observed in both black-hole and neutron-star X-ray binaries.
This work was supported by the NSF under grant PHY-97-22086.