Abstract
The dramatic discovery with the Rossi X-Ray Timing Explorer satellite of remarkably coherent ∼300–1200 Hz oscillations in the X-ray brightness of some sixteen neutron stars in low-mass binary systems has spurred theoretical modeling of these oscillations and investigation of their implications for the neutron stars and accretion flows in these systems. High-frequency oscillations are observed both during thermonuclear X-ray bursts and during intervals of accretion-powered emission and appear to be a characteristic feature of disk-accreting neutron stars with weak magnetic fields. In this review we focus on the high-frequency quasi-periodic oscillations (QPOs) seen in the accretion-powered emission. We first summarize the key properties of these kilohertz QPOs and then describe briefly the models that have been proposed to explain them. The existing evidence strongly favors beat-frequency models. We mention several of the difficulties encountered in applying the magnetospheric beat-frequency model to the kilohertz QPOs. The most fully developed and successful model is the sonic-point beat-frequency model. We describe the work on this model in some detail. We then discuss observations that could help to distinguish between models. We conclude by noting some of the ways in which study of the kilohertz QPOs may advance our understanding of dense matter and strong gravitational fields.
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
