scholarly journals The kHz QPOs of Neutron Stars and Millisecond Pulsars and Implications

2012 ◽  
Vol 8 (S290) ◽  
pp. 381-385
Author(s):  
Chengmin Zhang ◽  
Dehua Wang
Keyword(s):  
Magnetic Field ◽  
Low Frequency ◽  
Compact Objects ◽  
Periodic Oscillations ◽  
Disk Thickness ◽  
X Ray ◽  
Low Mass ◽  
Millisecond Timing ◽  
X Ray Binaries ◽  
Z Sources

AbstractThe kilohertz quasi-periodic oscillations (kHz QPOs) have been found in neutron star low mass X-ray binaries (NS-LMXBs), which present the millisecond timing phenomena close to the surface of the compact objects. We briefly summarize the following contents: (1). The correlations and distributions of twin kHz QPOs; (2). The relations of high-low frequency QPOs; (3). The QPO properties of NS Atoll and Z sources; (4). No clear direct correlations between NS spins and QPOs; (5). The mechanisms of kHz QPOs; (6). The implications of kHZ QPOs, e.g., NS mass and radius, disk thickness and magnetic field of Atoll and Z source.

scholarly journals Quasi-Periodic Oscillations in Low-Mass X-ray Binaries

1987 ◽  
Vol 125 ◽  
pp. 321-331
Author(s):  
M. van der Klis
Keyword(s):  
Neutron Star ◽  
Low Frequency ◽  
Frequency Noise ◽  
Low Frequency Noise ◽  
Periodic Oscillations ◽  
X Ray ◽  
Low Mass ◽  
X Ray Binaries

The properties of the rapid, persistent quasi-periodic oscillations (QPO) discovered with EXOSAT in the X-ray flux of at least 7 bright low-mass X-ray binaries are described. Particular attention is given to the various relations observed between QPO frequency and X-ray intensity, the link between QPO and the low-frequency noise in the X-ray intensity and the bimodal properties of in particular Sco X-1, GX 5-1 and Cyg X-2. The merits of the hypothesis that the QPO indicate the presence of a neutron star with a magnetosphere are considered.

scholarly journals On the frequency correlations of low-frequency QPOs with kilohertz QPOs in accreting millisecond X-ray pulsars

2019 ◽  
Vol 490 (4) ◽  
pp. 5270-5284 ◽  
Author(s):  
Marieke van Doesburgh ◽  
Michiel van der Klis
Keyword(s):  
Black Hole ◽  
Power Law ◽  
Equations Of State ◽  
Low Frequency ◽  
Data Sets ◽  
Periodic Oscillations ◽  
X Ray ◽  
Frame Dragging ◽  
Low Mass ◽  
X Ray Binaries

ABSTRACT We investigate frequency correlations of low frequency (LF, <80 Hz) and kHz quasi-periodic oscillations (QPOs) using the complete RXTE data sets on six accreting millisecond X-ray pulsars (AMXPs) and compare them to those of non-pulsating neutron star (NS) low-mass X-ray binaries with known spin. For the AMXPs SAX J1808.4−3658 and XTE J1807−294, we find frequency-correlation power-law indices that, surprisingly, are significantly lower than in the non-pulsars, and consistent with the relativistic precession model (RPM) prediction of 2.0 appropriate to test-particle orbital and Lense–Thirring precession frequencies. As previously reported, power-law normalizations are significantly higher in these AMXPs than in the non-pulsating sources, leading to requirements on the NS specific moment of inertia in this model that cannot be satisfied with realistic equations of state. At least two other AMXPs show frequency correlations inconsistent with those of SAX J1808.4−3658 and XTE J1807−294, and possibly similar to those of the non-pulsating sources; for two AMXPs no conclusions could be drawn. We discuss these results in the context of a model that has had success in black hole (BH) systems involving a torus-like hot inner flow precessing due to (prograde) frame dragging, and a scenario in which additional (retrograde) magnetic and classical precession torques not present in BH systems are also considered. We show that a combination of these interpretations may accommodate our results.

The possible origin of high frequency quasi-periodic oscillations in low mass X-ray binaries

2018 ◽  
Vol 14 (S346) ◽  
pp. 277-280
Author(s):  
Chang Sheng Shi ◽  
Shuang Nan Zhang ◽  
Xiang Dong Li
Keyword(s):  
Magnetic Field ◽  
High Frequency ◽  
Mhd Waves ◽  
Effective Surface ◽  
Periodic Oscillations ◽  
X Ray ◽  
Surface Magnetic Field ◽  
Low Mass ◽  
Mhd Model ◽  
X Ray Binaries

AbstractWe summarize our model that high frequency quasi-periodic oscillations (QPOs) both in the neutron star low mass X-ray binaries (NS-LMXBs) and black hole LMXBs may originate from magnetohydrodynamic (MHD) waves. Based on the MHD model in NS-LMXBs, the explanation of the parallel tracks is presented. The slowly varying effective surface magnetic field of a NS leads to the shift of parallel tracks of QPOs in NS-LMXBs. In the study of kilohertz (kHz) QPOs in NS-LMXBs, we obtain a simple power-law relation between the kHz QPO frequencies and the combined parameter of accretion rate and the effective surface magnetic field. Based on the MHD model in BH-LMXBs, we suggest that two stable modes of the Alfv́en waves in the accretion disks with a toroidal magnetic field may lead to the double high frequency QPOs. This model, in which the effect of the general relativity in BH-LMXBs is considered, naturally accounts for the 3:2 relation for the upper and lower frequencies of the QPOs and the relation between the BH mass and QPO frequency.

scholarly journals Pulsational Instability of Accretion Disks around Compact Objects

1993 ◽  
Vol 134 ◽  
pp. 361-364
Author(s):  
T. Okuda ◽  
S. Mineshige
Keyword(s):  
Accretion Disks ◽  
Cataclysmic Variables ◽  
Compact Object ◽  
Linear Analysis ◽  
Compact Objects ◽  
Periodic Oscillations ◽  
X Ray ◽  
Axisymmetric Perturbation ◽  
Low Mass ◽  
X Ray Binaries

AbstractLinear analysis shows that radial oscillations in accretion disks around compact object are overstable to axisymmetric perturbation under a variety of conditions. Furthermore, numerical simulations confirm that the radial oscillations induce quasi-periodic modulations of the disk luminosity. The disk oscillation model may be responsible for quasi-periodic oscillations (QPOs) observed in low mass X-ray binaries (LMXBs), cataclysmic variables (CVs), and other compact objects.

scholarly journals QPOs in compact binaries from small scale eruptions in an inner magnetized disk

2020 ◽  
Author(s):  
Nicolas Scepi ◽  
Mitchell C Begelman ◽  
Jason Dexter
Keyword(s):  
Rapid Heating ◽  
Small Scale ◽  
Type B ◽  
Periodic Oscillations ◽  
X Ray ◽  
Compact Binaries ◽  
Heating And Cooling ◽  
Low Mass ◽  
X Ray Binaries ◽  
Standard Disk

Abstract Dwarf novæ (DNe) and low mass X-ray binaries (LMXBs) are compact binaries showing variability on time scales from years to less than seconds. Here, we focus on explaining part of the rapid fluctuations in DNe, following the framework of recent studies on the monthly eruptions of DNe that use a hybrid disk composed of an outer standard disk and an inner magnetized disk. We show that the ionization instability, that is responsible for the monthly eruptions of DNe, is also able to operate in the inner magnetized disk. Given the low density and the fast accretion time scale of the inner magnetized disk, the ionization instability generates small, rapid heating and cooling fronts propagating back and forth in the inner disk. This leads to quasi-periodic oscillations (QPOs) with a period of the order of 1000 s. A strong prediction of our model is that these QPOs can only develop in quiescence or at the beginning/end of an outburst. We propose that these rapid fluctuations might explain a subclass of already observed QPOs in DNe as well as a, still to observe, subclass of QPOs in LMXBs. We also extrapolate to the possibility that the radiation pressure instability might be related to Type B QPOs in LMXBs.

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