相关论文: Alfven QPOs in magnetars in the anelastic approxim…
In this paper, results of 2.5-dimensional magnetohydrodynamical simulations are reported for the magnetic reconnection of non-perfectly antiparallel magnetic fields. The magnetic field has a component perpendicular to the computational…
Quasi-Periodic Oscillations (QPOs) have been observed during three powerful magnetar flares, from SGR0526-66, SGR1806-20 and SGR1900+14. These QPOs have been commonly interpreted as being driven by the mechanical modes of the magnetar's…
We consider torsional oscillations of magnetars. This problem features rich dynamics due to the strong interaction between the normal modes of a magnetar's crust and a continuum of Magneto-Hydro-Dynamic (MHD) modes in its fluid core. We…
Magnetars form a special class of neutron stars possessing superstrong magnetic fields and demonstrating power flares triggered likely by these fields. Observations of such flares reveal the presence of quasi-periodic oscillations (QPOs) at…
High-frequency quasi-periodic oscillations (QPOs) appear in general-relativistic magnetohydrodynamic simulations of magnetically choked accretion flows around rapidly rotating black holes (BHs). We perform polarized radiative transfer…
We study the conversion of fast magneto-acoustic waves to Alfven waves by means of 2.5D numerical simulations in a sunspot-like magnetic configuration. A fast, essentially acoustic, wave of a given frequency and wave number is generated…
Complete asymptotic expansions are developed for slow, Alfv\'en and fast magnetohydrodynamic waves at the base of an isothermal three-dimensional (3D) plane stratified atmosphere. Together with existing convergent Frobenius series solutions…
This is the second of a series of papers aimed to look for an explanation on the generation of high frequency quasi-periodic oscillations (QPOs) in accretion disks around neutron star, black hole, and white dwarf binaries. The model is…
We study the coupling of magneto-acoustic waves to Alven waves using 2.5D numerical simulations. In our experiment, a fast magnetoacoustic wave of a given frequency and wavenumber is generated below the surface. The magnetic field in the…
We demonstrate that in highly magnetized pair plasmas, nonlinear Alfven waves with wave-number $k \leq k_0 = \omega_p^2 /(\delta \omega_B)$ ($\delta =( \delta B)/B_0$ are relative fluctuations of the magnetic field) experience powerful…
Low and intermediate frequency quasi-periodic oscillations (QPOs) in black hole candidates are believed to be due to oscillations of the Comptonizing regions in an accretion flow. Assuming that the general structure of an accretion disk is…
We calculate analytical gravitational waveforms in the time- and frequency-domain for precessing quasi-circular binaries with spins of arbitrary magnitude, but nearly aligned with the orbital angular momentum. We first derive an analytical…
The quasi-periodic oscillations (QPOs) observed in the tails of magnetar giant $\gamma$-ray flares have long been interpreted as normal oscillation modes of these stars. However, most studies modelling QPOs have neglected some key features…
We ascribe the interpretation of the twin kilohertz Quasi Periodic Oscillations (kHz QPOs) of X-ray spectra of Low Mass X-Ray Binaries (LMXBs) to MHD Alfven wave oscillations in the different mass density regions of the accreted matter at…
The seismological dynamics of magnetars is largely determined by a strong hydro-magnetic coupling between the solid crust and the fluid core. In this paper we set up a "spectral" computational framework in which the magnetar's motion is…
We study the effect of superfluidity on torsional oscillations of highly magnetised neutron stars (magnetars) with a microphysical equation of state by means of two-dimensional, magnetohydrodynamical- elastic simulations. The superfluid…
We study axisymmetric perturbations of neutron star endowed with a strong magnetic field (magnetars), considering the coupled oscillations of the fluid core with the solid crust. We recover discrete oscillations based mainly in the crust…
Following our previous work of Lachowicz & Czerny (2005), we explore further the application of the continuous wavelet transform to X-ray astronomical signals. Using the public archive of the XMM-Newton satellite, we analyze all available…
This paper is devoted to the study of the gravitational instability of a medium permeated by a uniform magnetic field along which a circularly polarized Alfven wave propagates. We concentrate on the case of perturbations purely transverse…
We study large-amplitude, very oblique Alfv\'en waves at low $\beta$, with small gradient length scales, comparable to the ion inertial scale $d_i$. Such waves have large density fluctuations, and slight dispersion from finite-frequency and…