Hostname: page-component-586b7cd67f-2plfb Total loading time: 0 Render date: 2024-11-29T12:52:11.885Z Has data issue: false hasContentIssue false

Millisecond Time Variations of X-Ray Binaries

Published online by Cambridge University Press:  25 May 2016

J. H. Swank*
Affiliation:
NASA/GSFC Greenbelt, MD 20771, U.S.A.

Abstract

Core share and HTML view are not available for this content. However, as you have access to this content, a full PDF is available via the ‘Save PDF’ action button.

Millisecond time-scales are natural for some neutron star and black hole processes, although possibly difficult to observe. The Rossi X-Ray Timing Explorer (RXTE) has found that for the neutron stars in low-mass X-ray binaries (LMXB) there are flux oscillations at high frequencies, with large amplitudes. Z sources and bursters tend to exhibit oscillations in the range 300-1200 Hz. Persistent emission may exhibit one or both of two features. In bursts from different bursters, a nearly coherent pulsation is seen, which may be the rotation period of the neutron star. For some the frequency equals the difference between the two higher frequencies, suggesting a beat frequency model, but in others it is twice the difference. The sources span two orders of magnitude in accretion rate, yet the properties are similar. The similar maximum frequencies suggests that it corresponds to the Kepler orbit frequency at the minimum stable orbit or the neutron star surface, either of which would determine the neutron star masses, radii and equation of state. Theories of accretion onto black holes predict a quasi-periodic oscillation (QPO) related to the inner accretion disk. The two microquasar black hole candidates (BHCs) have exhibited candidates for this or related frequencies.

Type
Session 3: Diagnostics of High Gravity Objects with X- and Gamma Rays
Copyright
Copyright © Kluwer 1998 

References

1. Strohmayer, T. E., Zhang, W., Swank, J. H., Smale, A. P., Titarchuk, L., & Day, C. (1996) Millisecond X-Ray Variability from an Accreting Neutron Star System, Ap. J. Letters , 469, L9.Google Scholar
2. Remillard, R. E., Morgan, E. H., McClintock, J. E., Baiyln, C. D., Orosz, J. A., & Greiner, J. (1997) Multifrequency Observations of the Galactic Microquasars GRS 1915+105 and GRO J1655-40, Proceedings of 18th Texas Symposium on Relativistic Astrophysics , Eds. Olinto, A., Frieman, J., and Schramm, D., World Scientific Press.Google Scholar
3. van der Klis, M. (1997) Kilohertz Quasi-Periodic Oscillations in Low-Mass X-Ray Binaries, Proc. NATO ASI “The Many Faces of Neutron Stars” , in press.CrossRefGoogle Scholar
4. Strohmayer, T. E., Zhang, W., & Swank, J. H. (1997) 363 Hz Oscillations during the Rising Phase of Bursts from 4U 1728-34: Evidence for Rotational Modulation, Ap. J. Letters , 487, L77.Google Scholar
5. Miller, M. C., Lamb, F. K., & Psaltis, D. (1998) Sonic-Point Model for High-Frequency QPOs in Neutron Star Low-Mass X-Ray Binaries, Ap. J. Suppl. , in press.Google Scholar
6. Nowak, M. A., Wagoner, R. V., Begelman, M. C., & Lehr, D. E. (1997) The 67 Hz Feature in the Black Hole Candidate GRS 1915+105 as a Possible Diskoseismic Mode, Ap. J. Letters , 477, L91.Google Scholar
7. Zhang, W., Strohmayer, T., & Swank, J. H. (1997) Neutron Star Masses and Radii as inferred from Kilohertz Quasi-Periodic Oscillations, Ap. J. Letters , 482, L167.CrossRefGoogle Scholar
8. Kaaret, P., Ford, E. C., & Chen, K. Strong-Field General Relativity and Quasiperiodic Oscillations in X-Ray Binaries, Ap. J. Letters , 480, L27.Google Scholar
9. Zhang, S. N., Cui, W., & Chen, W. (1997) Black Hole Spin in X-Ray Binaries: Observational Consequences, Ap. J. Letters , 482, L155.Google Scholar