String loops oscillating in the field of Kerr black holes as a possible explanation of twin high-frequency quasiperiodic oscillations observed in microquasars

Stuchlík, Zdeněk; Kološ, Martin

doi:10.1103/physrevd.89.065007

Cited by 22 publications

(42 citation statements)

References 52 publications

(96 reference statements)

Supporting

Mentioning

Contrasting

Order By: Relevance

“…In the spacetimes with the repulsive cosmological term (and the related solutions of the f(R) gravity), motion of photons is treated in a series of papers [35][36][37][38][39][40][41][42][43][44][45], while motion of test particles was studied in [15,31,. Oscillatory motion of current carrying string loops in SdS and KdS spacetimes was treated in [69][70][71][72][73][74][75].…”

Section: Introductionmentioning

confidence: 99%

General relativistic polytropes with a repulsive cosmological constant

2016

View full text Add to dashboard Cite

Spherically symmetric equilibrium configurations of perfect fluid obeying a polytropic equation of state are studied in spacetimes with a repulsive cosmological constant. The configurations are specified in terms of three parameters-the polytropic index n, the ratio of central pressure and central energy density of matter σ, and the ratio of energy density of vacuum and central density of matter λ. The static equilibrium configurations are determined by two coupled first-order nonlinear differential equations that are solved by numerical methods with the exception of polytropes with n = 0 corresponding to the configurations with uniform distribution of energy density, when the solution is given in terms of elementary functions. The geometry of the polytropes is conveniently represented by embedding diagrams of both the ordinary space geometry and the optical reference geometry reflecting some dynamical properties of the geodesic motion. The polytropes are represented by radial profiles of energy density, pressure, mass, and metric coefficients. For all tested values of n > 0, the static equilibrium configurations with fixed parameters n, σ, are allowed only up to a critical value of the cosmological parameter λc = λc(n, σ). In the case of n > 3, the critical value λc tends to zero for special values of σ. The gravitational potential energy and the binding energy of the polytropes are determined and studied by numerical methods. We discuss in detail the polytropes with extension comparable to those of the dark matter halos related to galaxies, i.e., with extension ℓ > 100 kpc and mass M > 10 12 M⊙. For such largely extended polytropes the cosmological parameter relating the vacuum energy to the central density has to be larger than λ = ρvac/ρc ∼ 10 −9 . We demonstrate that extension of the static general relativistic polytropic configurations cannot exceed the so called static radius related to their external spacetime, supporting the idea that the static radius represents a natural limit on extension of gravitationally bound configurations in an expanding universe dominated by the vacuum energy.PACS numbers: 98.80. Es,

show abstract

Section: Introductionmentioning

confidence: 99%

General relativistic polytropes with a repulsive cosmological constant

2016

View full text Add to dashboard Cite

show abstract

“…Physical properties of the system are determined by an interplay of different factors which define the form of the fluid flow; they are, in particular, the gravitational and electromagnetic action of the central body and of the ambient fields. Effects of general relativity are particularly important and visible near horizon of a black hole or neutron star, nevertheless, even a mildly charged matter is strongly influenced by external magnetic fields to which the black hole may be embedded [11][12][13][14][15][16].…”

Section: Introductionmentioning

confidence: 99%

Electrically charged matter in rigid rotation around magnetized black hole

et al. 2014

View full text Add to dashboard Cite

We study charged-fluid toroidal structures surrounding a non-rotating charged black hole immersed in a large-scale, asymptotically uniform magnetic field. In continuation of our former study on electrically charged matter in approximation of zero conductivity, we demonstrate existence of orbiting structures in permanent rigid rotation in the equatorial plane, and charged clouds hovering near the symmetry axis. We constrain the range of parameters that allow stable configurations and derive the geometrical shape of equi-pressure surfaces. Our simplified analytical study suggests that these regions of stability may be relevant for trapping electrically charged particles and dust grains in some areas of the black hole magnetosphere, being thus important in some astrophysical situations.

show abstract

“…For black holes with an external magnetic field, the motion is generally of chaotic character, but in vicinity of the local minima of the effective potential the motion is simplified and corresponds to linear harmonic oscillations or quasi-harmonic oscillation with frequencies close to those of the harmonic motion. The quasi-harmonic oscillations around a stable equilibrium location can be relevant for explanation of the HF QPOs observed in the three microquasars GRS 1915+105, XTE 1550-564, and GRO 1655-40 [2,40].…”

Section: Introductionmentioning

confidence: 99%

Quasi-harmonic oscillatory motion of charged particles around a Schwarzschild black hole immersed in a uniform magnetic field

Kološ

Stuchlík

Tursunov

2015

Class. Quantum Grav.

158

156

View full text Add to dashboard Cite

In order to test the role of large-scale magnetic fields in quasiperiodic oscillation phenomena observed in microquasars, we study oscillatory motion of charged particles in vicinity of a Schwarzschild black hole immersed into an external asymptotically uniform magnetic field. We determine the fundamental frequencies of small harmonic oscillations of charged test particles around stable circular orbits in the equatorial plane of a magnetized black hole, and discuss the radial profiles of frequencies of the radial and latitudinal harmonic oscillations in dependence on the mass of the black hole and the strength of the magnetic field. We demonstrate that assuming relevance of resonant phenomena of the radial and latitudinal oscillations of charged particles at their frequency ratio 3 : 2, the oscillatory frequencies of charged particles can be well related to the frequencies of the twin high-frequency quasi-periodic oscillations observed in the microquasars GRS 1915+105, XTE 1550-564 and GRO 1655

show abstract

String loops oscillating in the field of Kerr black holes as a possible explanation of twin high-frequency quasiperiodic oscillations observed in microquasars

Cited by 22 publications

References 52 publications

General relativistic polytropes with a repulsive cosmological constant

General relativistic polytropes with a repulsive cosmological constant

Electrically charged matter in rigid rotation around magnetized black hole

Quasi-harmonic oscillatory motion of charged particles around a Schwarzschild black hole immersed in a uniform magnetic field

Contact Info

Product

Resources

About