Gravitational excitation of high frequency QPOs

Publication date: Oct 2008

Abstract:
We discuss the possibility that high-frequency QPOs in neutron-star binary

systems may result from forced resonant oscillations of matter in the

innermost parts of the accretion disc, excited by gravitational perturbations

coming from asymmetries of the neutron star or from the companion star. We

find that neutron-star asymmetries could, in principle, be effective for

inducing both radial and vertical oscillations of relevant amplitude while

the binary companion might possibly produce significant radial oscillations

but not vertical ones. Misaligned neutron-star quadrupole moments of a size

advocated elsewhere for explaining limiting neutron star periods could be

large enough also for the present purpose.

Authors:
Stuchlík, Z.; Konar, S.; Miller, J. C.; Hledík, S.;