Transonic Magnetic Slim Accretion Disks and Kilohertz Quasi‐periodic Oscillations in Low‐Mass X‐Ray Binaries

Abstract A possible origin of kilohertz quasi-periodic oscillations (QPOs) in low-mass X-ray binaries is proposed. Recent numerical magnetohydrodynamic simulations of accretion disks with turbulent magnetic fields of magneto-rotational instability definitely show the presence of two-armed spiral structure in the quasi-steady state of accretion disks. In such deformed disks, two-armed ($m=2$) c-mode ($n=1$) oscillations are excited by wave–wave resonant instability. Among these excited oscillations, the fundamental in the radial direction ($n_{\rm r}=0$) will be the higher kHz QPO of twin QPOs, and the first overtone ($n_{\rm r}=1$) in the radial direction will be the lower kHz QPO of the twin. A possible cause of the twin high-frequency QPOs in black hole X-ray binaries is also discussed in the final section.

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Pulsational Instability of Accretion Disks around Compact Objects

International Astronomical Union Colloquium ◽

10.1017/s0252921100014470 ◽

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.

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

Monthly Notices of the Royal Astronomical Society ◽

10.1093/mnras/staa3410 ◽

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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A possible explanation of the parallel tracks in kilohertz quasi-periodic oscillations from low-mass-X-ray binaries

Monthly Notices of the Royal Astronomical Society ◽

10.1093/mnras/sty1191 ◽

2018 ◽

Cited By ~ 2

Author(s):

Chang-Sheng Shi ◽

Shuang-Nan Zhang ◽

Xiang-Dong Li

Keyword(s):

Periodic Oscillations ◽

X Ray ◽

Low Mass ◽

X Ray Binaries

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GRO J1744-28 and the Rapid Burster; Bizarre Objects!

Symposium - International Astronomical Union ◽

10.1017/s007418090011455x ◽

1998 ◽

Vol 188 ◽

pp. 111-111

Author(s):

Walter H.G. Lewin

Keyword(s):

Type Ii ◽

Time Intervals ◽

Periodic Oscillations ◽

X Ray ◽

Magnetic Dipole Field ◽

Order Of Magnitude ◽

Low Mass ◽

Type Ii Bursts ◽

The Difference ◽

X Ray Binaries

The bursts from GRO J1744-28 are due to accretion instabilities as is the case for type II bursts in the Rapid Burster. Both sources are transient Low-Mass X-ray Binaries, and they both exhibit unusual quasi-periodic-oscillations in their persistent X-ray flux following several (not all) of the type II bursts. There are important differences too. GRO J1744-28 is an X-ray pulsar; the Rapid Burster is not. In addition, the pattern of bursts and the burst peak luminosities are very different for the two sources. Time intervals between the rapidly repetitive bursts in the Rapid Burster can be as short as 10 sec, in 1744-28 they are as short as 200 sec. The peak luminosities of the bursts from GRO J1744-28 can exceed the Eddington luminosity (for assumed isotropic emission) by one to two orders of magnitude. The QPO centroid frequencies (see above) differ by an order of magnitude (~0.04 Hz for the Rapid Burster, and 0.3 Hz for GRO J1744-28). The difference in behavior p obably lies in the difference in the magnetic dipole field strength of the accreting neutron stars (for GRO J1744-28 it is almost certainly much higher than for the Rapid Burster). It remains puzzling, why GRO J1744-28 and the Rapid Burster are the only known sources which exhibit rapidly repetitive type II bursts.

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Modeling of Oxygen-Neon Dominated Accretion Disks in Ultracompact X-Ray Binaries: 4U 1626-67

International Astronomical Union Colloquium ◽

10.1017/s025292110015225x ◽

2004 ◽

Vol 194 ◽

pp. 146-147 ◽

Cited By ~ 2

Author(s):

K. Werner ◽

T. Nagel ◽

S. Dreizler ◽

T. Rauch

Keyword(s):

Accretion Disks ◽

Important Process ◽

Gravitational Settling ◽

X Ray ◽

The Core ◽

Synthetic Spectra ◽

First Results ◽

Low Mass ◽

X Ray Binaries

AbstractWe report on first results of computing synthetic spectra from H/He-poor accretion disks in ultracompact LMXBs. We aim at the determination of the chemical composition of the very low-mass donor star, which is the core of a former C/O white dwarf. The abundance analysis allows to draw conclusions on gravitational settling in WDs which is an important process affecting cooling times and pulsational g-mode periods.

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The Beat-Frequency Interpretation of Kilohertz Quasi-periodic Oscillations in Neutron Star Low-Mass X-Ray Binaries

The Astrophysical Journal ◽

10.1086/311455 ◽

1998 ◽

Vol 501 (1) ◽

pp. L95-L99 ◽

Cited By ~ 54

Author(s):

Dimitrios Psaltis ◽

Mariano Méndez ◽

Rudy Wijnands ◽

Jeroen Homan ◽

Peter G. Jonker ◽

...

Keyword(s):

Neutron Star ◽

Beat Frequency ◽

Periodic Oscillations ◽

X Ray ◽

Frequency Interpretation ◽

Low Mass ◽

X Ray Binaries

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A review of quasi-periodic oscillations in low-mass X-ray binaries

Space Science Reviews ◽

10.1007/bf00212242 ◽

1988 ◽

Vol 46 (3-4) ◽

pp. 273-377 ◽

Cited By ~ 67

Author(s):

Walter H. G. Lewin ◽

Jan Van Paradijs ◽

Michiel Van der Klis

Keyword(s):

Periodic Oscillations ◽

X Ray ◽

Low Mass ◽

X Ray Binaries

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Magnetically Driven Warping and Precession of Accretion Disks: Implications for Exotic Stellar Variabilities

International Astronomical Union Colloquium ◽

10.1017/s0252921100001421 ◽

2002 ◽

Vol 187 ◽

pp. 215-220

Author(s):

Dong Lai

Keyword(s):

Accretion Disks ◽

Low Frequency ◽

Disk Accretion ◽

X Ray ◽

T Tauri ◽

Magnetic Stars ◽

Low Mass ◽

Inner Region ◽

X Ray Binaries

AbstractThe inner region of the accretion disk around a magnetized star is subjected to magnetic torques that induce warping and precession of the disk. These torques arise from interactions between the stellar field and the induced electric currents in the disk. These novel magnetic effects give rise to some “exotic” stellar variabilities, and may play an important role in explaining a number of puzzling behaviors related to disk accretion onto magnetic stars, such as mHz QPOs in X-ray pulsars, long-term periodicities of X-ray binaries (including precession of jets), low-Frequency (10-50 Hz) QPO’s in low-mass X-ray binaries, and photometric variabilities of T Tauri stars.

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