A possible mechanism for QPOs modulation in neutron star sources

Abstract

It was pointed out by Paczynski (1987) that the X-ray luminosity of accreting neutron stars is very sensitive to the physical properties of the accretion flow close to the innermost stable circular orbit. The X-ray radiation is dominated by that emitted in the boundary layer, where accreted matter hits a star surface. The X-ray luminosity of the boundary layer is proportional to the local accretion rate. In this note, we estimate local accretion rate variations from the disk that undergoes non-stationary axisymmetric perturbations. The perturbations are given by the poloidal-velocity potential. We obtain a simple formula describing the modulation of the accretion rate for the particular case of global vertical disk oscillations that have been recently studied by Abramowicz et al. (2005).

5 pages, 2 figures

References in corpus (2)

• The upper kHz QPO: a gravitationally lensed vertical oscillation
• Oscillations of Thick Accretion Discs Around Black Holes

Cited by in corpus (7)

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• Models of high-frequency quasi-periodic oscillations and black hole spin estimates in Galactic microquasars
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• Difficulties with the QPOs Resonance Model
• Simple analytic formula relating the mass and spin of accreting compact objects to their rapid X-ray variability
• QPOs in microquasars: the spin problem