A GENERAL RELATIVISTIC MAGNETOHYDRODYNAMIC MODEL OF HIGH FREQUENCY QUASI-PERIODIC OSCILLATIONS IN BLACK HOLE LOW-MASS X-RAY BINARIES

AbstractThe physical origin of high-frequency QPOs (HFQPOs) in black-hole X-ray binaries remains an enigma despite many years of detailed observational studies. Although there exists a number of models for HFQPOs, many of these are simply “notions” or “concepts” without actual calculation derived from fluid or disk physics. Future progress requires a combination of numerical simulations and semi-analytic studies to extract physical insights. We review recent works on global oscillation modes in black-hole accretion disks, and explain how, with the help of general relativistic effects, the energy stored in the disk differential rotation can be pumped into global spiral density modes in the disk, making these modes grow to large amplitudes under certain conditions (“corotational instability”). These modes are robust in the presence of disk magnetic fields and turbulence. The computed oscillation mode frequencies are largely consistent with the observed values for HFQPOs in BH X-ray binaries. The approximate 2:3 frequency ratio is also expected from this model. The connection of HFQPOs with other disk properties (such as production of episodic jets) is also discussed.

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Rossby wave instability and high-frequency quasi-periodic oscillations in accretion discs orbiting around black holes

Astronomy and Astrophysics ◽

10.1051/0004-6361/201935208 ◽

2019 ◽

Vol 625 ◽

pp. A116 ◽

Cited By ~ 2

Author(s):

P. Varniere ◽

F. Casse ◽

F. H. Vincent

Keyword(s):

Black Holes ◽

Black Hole ◽

Rossby Wave ◽

High Frequency ◽

Binary Systems ◽

Wave Instability ◽

Periodic Oscillations ◽

X Ray ◽

General Relativistic ◽

Frequency Ratios

Context. The rather elusive high-frequency quasi-periodic oscillations (HFQPOs) observed in the X-ray light curve of black holes have been seen in a wide range of frequencies, even within one source. Also notable is the detection of “pairs” of HFQPOs with a close-to-integer ratio between the frequencies. Aims. The aim of this paper is to investigate some of the possible observables that we could obtain from the Rossby wave instability (RWI) active in the accretion disc surrounding the compact object. Methods. Using the newly developed GR-AMRVAC code able to follow the evolution of the RWI in a full general relativistic framework, we explore how RWI can reproduce observed HFQPO frequency ratios and whether or not it is compatible with observations. In order to model the emission coming from the disc we have linked our general relativistic simulations to the general relativistic ray-tracing GYOTO code and delivered synthetic observables that can be confronted with actual data from binary systems hosting HFQPOs. Results. We demonstrate that some changes in the physical conditions prevailing in the part of the disc where RWI can be triggered lead to various dominant RWI modes whose ratio recovers frequency ratios observed in various X-ray binary systems. In addition we also show that when RWI is triggered near to the last stable orbit of a spinning black hole, the amplitude of the X-ray modulation increases with the spin of the black hole. Revisiting published data on X-ray binary systems, we show that this type of relationship actually exists in five systems where an indirect measurement of the spin of the black hole is available.

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

Monthly Notices of the Royal Astronomical Society ◽

10.1093/mnras/stz2622 ◽

2019 ◽

Vol 490 (4) ◽

pp. 5270-5284 ◽

Cited By ~ 5

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.

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

Proceedings of the International Astronomical Union ◽

10.1017/s1743921319001832 ◽

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.

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Energy spectra of X-ray quasi-periodic oscillations in accreting black hole binaries

Proceedings of the International Astronomical Union ◽

10.1017/s1743921307004607 ◽

2006 ◽

Vol 2 (S238) ◽

pp. 13-18

Author(s):

P. T. Życki ◽

M. A. Sobolewska ◽

A. Niedźwiecki

Keyword(s):

Black Hole ◽

High Frequency ◽

Energy Spectra ◽

Periodic Oscillations ◽

X Ray ◽

Black Hole Binaries ◽

Hot Plasma ◽

X Ray Binaries ◽

Disk Component

AbstractWe investigate the energy dependencies of X-ray quasi-periodic oscillations in black hole X-ray binaries. We analyze RXTE data on both the low- and high-frequency QPO. We construct the low-f QPO energy spectra, and demonstrate that they do not contain the thermal disk component, even though the latter is present in the time averaged spectra. The disk thus does not seem to participate in the oscillations. Moreover the QPO spectra are harder than the time averaged spectra when the latter are soft, which can be modeled as a result of modulations occurring in the hot plasma. The QPO spectra are softer than the time averaged spectra when the latter are hard. The absence of the disk component in the QPO spectra is true also for the high-frequency (hecto-Hz) QPO observed in black hole binaries. We compute the QPO spectra expected from the model of disk resonances.

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Quasi-Periodic Oscillations: The Rapid Burster (MXB 1730-335): Models vs. Observations - A Brief Review

Symposium - International Astronomical Union ◽

10.1017/s0074180900160954 ◽

1987 ◽

Vol 125 ◽

pp. 363-374

Author(s):

Walter H. G. Lewin

Keyword(s):

High Frequency ◽

Periodic Oscillations ◽

X Ray ◽

Low Mass ◽

Salient Features ◽

X Ray Binaries

The salient features of quasi-periodic oscillations (QPO) observed in type 2 bursts and in the persistent emission from the Rapid Burster are discussed. In addition, a brief review is given of the models that have recently been proposed to explain high-frequency QPO observed in several bright low-mass X-ray binaries. We do not yet know the mechanism(s) of the QPO, not even whether they are magnetospheric in origin. However, some of the proposed ideas could well be relevant to the various rather complex aspects of the QPO. It is likely that more than one mechanism is at work.

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