Disc-oscillation resonance and neutron star QPOs: 3:2 epicyclic orbital model

Urbanec, Martin; Török, Gabriel; Šrámková, Eva; Cech, Petr; Stuchlík, Zdeněk; Bakala, Pavel

doi:10.1051/0004-6361/201014731

Cited by 16 publications

(15 citation statements)

References 85 publications

(95 reference statements)

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“…As emphasized by Urbanec et al (2010b), , Kluźniak & Rosińska (2013), Török et al (2014), Rosińska et al (2014) and Boshkayev et al (2015), Newtonian effects following from the influence of the quadrupole moment act on the orbital frequencies in a way opposite to that which is related to relativis- tic effects following from the increase of the angular momentum. The behaviour of the relations shown in the left panel of Figure 3 is determined by this interplay.…”

Section: Results For the Rp Modelmentioning

confidence: 98%

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Constraining Models of Twin-Peak Quasi-Periodic Oscillations With Realistic Neutron Star Equations of State

Török

Goluchová

Urbanec

et al. 2016

ApJ

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Twin-peak quasi-periodic oscillations (QPOs) are observed in the X-ray power-density spectra of several accreting low-mass neutron star (NS) binaries. In our previous work we have considered several QPO models. We have identified and explored mass-angular-momentum relations implied by individual QPO models for the atoll source 4U 1636-53. In this paper we extend our study and confront QPO models with various NS equations of state (EoS). We start with simplified calculations assuming Kerr background geometry and then present results of detailed calculations considering the influence of NS quadrupole moment (related to rotationally induced NS oblateness) assuming Hartle-Thorne spacetimes. We show that the application of concrete EoS together with a particular QPO model yields a specific mass-angular-momentum relation. However, we demonstrate that the degeneracy in mass and angular momentum can be removed when the NS spin frequency inferred from the X-ray burst observations is considered. We inspect a large set of EoS and discuss their compatibility with the considered QPO models. We conclude that when the NS spin frequency in 4U 1636-53 is close to 580Hz we can exclude 51 from 90 of the considered combinations of EoS and QPO models. We also discuss additional restrictions that may exclude even more combinations. Namely, there are 13 EOS compatible with the observed twin peak QPOs and the relativistic precession model. However, when considering the low frequency QPOs and Lense-Thirring precession, only 5 EOS are compatible with the model.

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Section: Results For the Rp Modelmentioning

confidence: 98%

“…These can be confronted with models of rotating NS based on a modern equation of state (EoS, e.g. Urbanec et al 2010b). In Török et al (2012) we have identified and explored mass-angular-momentum relations implied in Kerr spacetimes by individual QPO models.…”

Section: Aims and Scope Of This Papermentioning

confidence: 99%

Constraining Models of Twin-Peak Quasi-Periodic Oscillations With Realistic Neutron Star Equations of State

Török

Goluchová

Urbanec

et al. 2016

ApJ

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“…Abramowicz et al (2003a,b); Kluźniak & Abramowicz (2001) introduced the resonance model with the upper frequency corresponding to the vertical epicyclic frequency and the lower frequency corresponding to the radial epicyclic frequency, which accords with observational data quite well in the black-hole binary systems (Török et al, 2005. But the last two models show the inconsistent with the subsequent twin kHz QPO observations (Belloni et al, 2007;Jonker et al, 2002a;Muno, 2004;Strohmayer & Bildsten, 2006;Urbanec et al, 2010;van der Klis, 2006;Wijnands et al, 2003;Zhang et al, 2006a).…”

Section: Introductionmentioning

confidence: 78%

Statistical properties of twin kilohertz quasi‐periodic oscillations in neutron star low‐mass X‐ray binaries

et al. 2014

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We collect the data of twin kilohertz quasi-periodic oscillations (kHz QPOs) published before 2012 from 26 neutron star (NS) low-mass X-ray binary (LMXB) sources, then we analyze the centroid frequency (ν) distribution of twin kHz QPOs (lower frequency ν1 and upper frequency ν2) both for Atoll and Z sources. For the data without shift-and-add, we find that Atoll and Z sources show the different distributions of ν1, ν2 and ν2/ν1, but the same distribution of ∆ν (difference of twin kHz QPOs), which indicates that twin kHz QPOs may share the common properties of LXMBs and have the same physical origins. The distribution of ∆ν is quite different from constant value, so is ν2/ν1 from constant ratio. The weighted mean values and maxima of ν1 and ν2 in Atoll sources are slightly higher than those in Z sources. We also find that shift-and-add technique can reconstruct the distribution of ν1 and ∆ν. The K-S test results of ν1 and ∆ν between Atoll and Z sources from data with shift-and-add are quite different from those without it, and we think that this may be caused by the selection biases of the sample. We also study the properties of the quality factor (Q) and the root-mean-squared (rms) amplitude of 4U 0614+09 with the data from the two observational methods, but the errors are too big to make a robust conclusion. The NS spin frequency (νs) distribution of 28 NS-LMXBs show a bigger mean value (∼ 408 Hz) than that (∼ 281 Hz) of the radio binary millisecond pulsars (MSPs), which may be due to the lack of the spin detections from Z sources (systematically lower than 281 Hz). Furthermore, on the relations between the kHz QPOs and NS spin frequency νs, we find the approximate correlations of the mean values of ∆ν with NS spin and its half, respectively.

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“…where C depends on the NS structure and equation of state [29][30][31]. For a NS of radius R = 11 km and mass M = 1.5 M , we choose C = 1.1 .…”

Section: Emission From Ns Surfacementioning

confidence: 99%

Three-dimensional general relativistic Poynting-Robertson effect. II. Radiation field from a rigidly rotating spherical source

et al. 2019

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We investigate the three-dimensional, general relativistic Poynting-Robertson (PR) effect in the case of rigidly rotating spherical source which emits radiation radially in the local comoving frame. Such radiation field is meant to approximate the field produced by the surface of a rotating neutron star, or by the central radiating hot corona of accreting black holes; it extends the purely radial radiation field that we considered in a previous study. Its angular momentum is expressed in terms of the rotation frequency and radius of the emitting source. For the background we adopt a Kerr spacetime geometry. We derive the equations of motion for test particles influenced by such radiation field, recovering the classical and weak-field approximation for slow rotation. We concentrate on solutions consisting of particles orbiting along circular orbits off and parallel to the equatorial plane, which are stabilized by the balance between gravitational attraction, radiation force and PR drag. Such solutions are found to lie on a critical hypersurface, whose shape may morph from prolate to oblate depending on the Kerr spin parameter and the luminosity, rotation and radius of the radiating sphere. For selected parameter ranges, the critical hypersurface intersects the radiating sphere giving rise to a bulging equatorial region or, alternatively, two lobes above the poles. We calculate the trajectories of test particles in the close vicinity of the critical hypersurface for a selected set of initial parameters and analyze the spatial and angular velocity of test particles captured on the critical hypersurface.

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Disc-oscillation resonance and neutron star QPOs: 3:2 epicyclic orbital model

Cited by 16 publications

References 85 publications

Constraining Models of Twin-Peak Quasi-Periodic Oscillations With Realistic Neutron Star Equations of State

Constraining Models of Twin-Peak Quasi-Periodic Oscillations With Realistic Neutron Star Equations of State

Statistical properties of twin kilohertz quasi‐periodic oscillations in neutron star low‐mass X‐ray binaries

Three-dimensional general relativistic Poynting-Robertson effect. II. Radiation field from a rigidly rotating spherical source

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