| 1. |
- Abramowicz, Marek A, 1945, et al.
(author)
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A note on the slope-shift anticorrelation in the neutron star kHz QPOs data
- 2005
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In: n Proceedings of RAGtime 6/7: Workshops on black holes and neutron stars. - 807248334X
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Conference paper (peer-reviewed)abstract
- Observations show that the upper νU and lower νL of the ``twin peak'' high frequency QPOs in neutron star sources vary along lines νU = AνL + B in a frequency-frequency plot, and that their ratios νU/νL cluster near the value 3/2. This behaviour is well consistent with the predictions of the non-linear resonance model for QPOs. In this Note, we further explore our recent finding that the coefficients A, B of the frequency-frequency lines for individual sources are anticorrelated. In the (A,B) plane, they occupy rather a narrow region along the line A = 3/2 - B/600 Hz. We show that this observational property of QPOs also follows from the resonance model
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| 2. |
- Abramowicz, Marek A, 1945, et al.
(author)
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The Twin Peak QPOs in Neutron Star and Black Hole Sources: What is explained, and What is not
- 2007
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In: Revista Mexicana de Astronomía y Astrofísica (Serie de Conferencias). ; 27, s. 8-17
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Conference paper (peer-reviewed)abstract
- The resonance model proposed in 2000 by Kluzniak and Abra-mo-wicz, explains the twin peak, high frequency, quasi periodic oscillations (HF QPOs) observed in the X-ray flux from black hole and neutron stars, as a non-linear resonance in modes of oscillations of accretion flows in strong gravity. While several important physical questions remain unanswered, recent observations of HF QPOs provide direct evidence of non-linear resonances. This article gives an up to date (May 2006) review of what has been explained, and what has not been explained, by the resonance model.
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| 3. |
- Kluzniak, W., et al.
(author)
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QPOs and Resonance in Accretion Disks
- 2007
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In: Revista Mexicana de Astronomía y Astrofísica (Serie de Conferencias). ; 27, s. 18-25
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Conference paper (peer-reviewed)abstract
- We review arguments suggesting that millisecond variability detected in the X-ray flux of LMXBs has its origin in oscillation modes of the accretion disk. The twin high-frequency QPOs observed in microquasars seem to be related to the twin kHz QPOs in neutron-star systems, and both phenomena are likely the result of a non-linear resonance in the accretion disk that is possible only in strong-field gravity. A presumed 3:2 eigenfrequency ratio of the resonant modes corresponds to the 3:2 QPO frequency ratio clearly detected in black-hole systems, as well as to the more complex distribution of kHz QPO frequency pairs in neutron stars.
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