Alfvén QPOs in magnetars in the anelastic approximation

@inproceedings{CerdDurn2009AlfvnQI,
  title={Alfv{\'e}n QPOs in magnetars in the anelastic approximation},
  author={Pablo Cerd{\'a}-Dur{\'a}n and Nikolaos Stergioulas and Jos{\'e} A. Font},
  year={2009}
}
We perform two-dimensional simulations of Alfven oscillations in magnetars, modeled as relativistic stars with a dipolar magnetic field. We use the a nelastic approximation to general relativistic magnetohydrodynamics, which allows for an effective suppression of fluid modes and an accurate description of Alfven waves. In addition, we compute Alfven oscillation fre- quencies along individual magnetic field lines with a semi-a nalytic approach, employing a short-wavelength approximation. Our… 

Figures and Tables from this paper

Magnetoelastic oscillations of neutron stars with dipolar magnetic fields
By means of two dimensional, general-relativistic, magneto-hydrodynamical simulations we investigate the oscillations of magnetized neutron star models (magnetars) including the de- scription of an
Relativistic MHD simulations of stellar core collapse and magnetars
We present results from simulations of magneto-rotational stellar core collapse along with Alfvén oscillations in magnetars. These simulations are performed with the CoCoA/CoCoNuT code, which is able
Quasi-periodic oscillations in superfluid magnetars
We study the time-evolution of axisymmetric oscillations of superfluid magnetars with a poloidal magnetic field and an elastic crust, working in Newtonian gravity. Extending earlier models, we study
Magneto-elastic oscillations modulating the emission of magnetars
Magneto-elastic oscillations of neutron stars are believed to explain observed quasi-periodic oscillations (QPOs) in the decaying tail of the giant flares of highly magnetized neutron stars
Axisymmetric toroidal modes of general relativistic magnetized neutron star models
We calculate axisymmetric toroidal modes of magnetized neutron stars with a solid crust in the general relativistic Cowling approximation. We assume that the interior of the star is threaded by a
Modulating magnetar emission by magneto-elastic oscillations
We present a new numerical tool to calculate the emission of highly magnetized neutron stars (magnetars) and apply it to describe the quasi-periodic oscillations (QPOs) observed in magnetar giant
Oscillations and instabilities in neutron stars with poloidal magnetic fields
We study the time evolution of non-axisymmetric linear perturbations of a rotating magnetized neutron star, whose magnetic field is purely poloidal. The background stellar configurations are
Oscillations of rotating magnetized neutron stars with purely toroidal magnetic fields
We investigate the oscillation spectrum of rotating Newtonian neutron stars endowed with purely toroidal magnetic fields, using a time-evolution code to evolve linear perturbations in the Cowling
Magnetar oscillations – II. Spectral method
The seismological dynamics of magnetars are largely determined by a strong hydromagnetic coupling between the solid crust and the fluid core. In this paper, we set up a ‘spectral’ computational
Non-axisymmetric low-frequency oscillations of rotating and magnetized neutron stars
We investigate non-axisymmetric low-frequency modes of a rotating and magnetized neutron star, assuming that the star is threaded by a dipole magnetic field whose strength at the stellar surface, B 0
...
...

References

SHOWING 1-10 OF 24 REFERENCES
Torsional Oscillations of Relativistic Stars with Dipole Magnetic Fields II. Global Alfven Modes
We investigate torsional Alfven modes of relativistic stars with a global dipole mag- netic field. It has been noted recently (Glampedakis et al. 2006) that such oscillation modes could serve as as
Axisymmetric toroidal modes of magnetized neutron stars
We calculate axisymmetric toroidal modes of magnetized neutron stars with a solid crust. We assume the interior of the star is threaded by a poloidal magnetic field that is continuous at the surface
Neutron star asteroseismology. Axial crust oscillations in the Cowling approximation
Recent observations of quasi-periodic oscillations in the aftermath of giant flares in soft gamma-ray repeaters suggest a close coupling between the seismic motion of the crust after a major quake
QPOs during magnetar flares are not driven by mechanical normal modes of the crust
QPOs have been observed during three powerful magnetar flares, from SGR 0526−66, SGR 1806−20 and SGR 1900+14. These QPOs have been commonly interpreted as being driven by the mechanical modes of the
Axisymmetric oscillations of magnetic neutron stars
We calculate axisymmetric oscillations of rotating neutron stars composed of the surface fluid ocean, solid crust and fluid core, taking account of a dipole magnetic field as strong as B s ∼ 10 15 G
Alfvén polar oscillations of relativistic stars
We study polar Alfven oscillations of relativistic stars endowed with a strong global poloidal dipole magnetic field. Here, we focus only on the axisymmetric oscillations which are studied by
A new general relativistic magnetohydrodynamics code for dynamical spacetimes
We present a new numerical code that solves the general relativistic magneto-hydrodynamical (GRMHD) equations coupled to the Einstein equations for the evolution of a dynamical spacetime within a
Superfluid signatures in magnetar seismology
We investigate the role of neutron star superfluidity for magnetar oscillations. Using a plane-wave analysis, we estimate the effects of a neutron superfluid in the elastic crust region. We
Numerical 3+1 General Relativistic Magnetohydrodynamics: A Local Characteristic Approach
We present a general procedure to solve numerically the general relativistic magnetohydrodynamics (GRMHD) equations within the framework of the 3+1 formalism. The work reported here extends our
...
...