相关论文: Rotational Instabilities and Centrifugal Hangup
We have performed hydrodynamic simulations of relativistic rotational supernova core collapse in axisymmetry and have computed the gravitational radiation emitted by such an event. Details of the methodology and of the numerical code have…
Rapidly rotating neutron stars can be unstable to the gravitational-wave-driven CFS mechanism if they have a neutral point in the spectrum of nonaxisymmetric f-modes. We investigate the frequencies of these modes in two sequences of…
We find that nuclear rings in barred galaxies can be subject to a new type of non-self-gravitational dynamical instability. The instability leads to the formation of gaseous molecular bars with pattern speeds which are substantially slower…
The Rossby mode (r-mode) perturbations in pulsars as a steady gravitational wave (GW) sources have been explored. The time evolution and the intensity of the emitted GWs in terms of the strain tensor amplitude have been estimated with the…
Spiral density waves can arise in galactic disks as linear instabilities of the underlying stellar distribution function. Such an instability grows exponentially in amplitude at some fixed growth rate $\beta$ before saturating nonlinearly.…
We present an analytic description of the $r$-mode instability in newly-born neutron stars, using the approximation of uniform density. Our computation is consistently accurate to second order in the angular velocity of the star. We obtain…
The dynamical stability of disk galaxies is sensitive to whether their anomalous rotation curves are caused by dark matter halos or Milgromian Dynamics (MOND). We investigate this by setting up a MOND model of M33. We first simulate it in…
Two classes of high energy sources in our galaxy are believed to host magnetars, neutron stars whose emission results from the dissipation of their magnetic field. The extremely high magnetic field of magnetars distorts their shape, and…
We study oscillations and instabilities of relativistic stars using perturbation theory in general relativity and take into account the contribution of a dynamic spacetime. We present the oscillation spectrum as well as the critical values…
We present results from detailed general relativistic simulations of stellar core collapse to a proto-neutron star, using two different microphysical nonzero-temperature nuclear equations of state as well as an approximate description of…
A strong candidate for a source of gravitational waves is a highly magnetised, rapidly rotating neutron star (magnetar) deformed by internal magnetic stresses. We calculate the mass quadrupole moment by perturbing a zeroth-order hydrostatic…
Direct observations of gravitational waves will open in the near future new windows on the Universe. Among the expected sources, instabilities of rotating compact astrophysical objects are waited to be detected with some impatience as this…
We perform fully general relativistic simulations of rotating stellar core collapse in three spatial dimension. A parametric equation of state is adopted following Dimmelmeier et al. The early stage of the collapse is followed by an…
Radiation-pressure instability was identified soon after the seminal classical accretion disk models of Shakura-Sunyaev and Novikov-Thorne, yet its full implications remain an active area of investigation. These models form the backbone of…
The dynamics of hexagon patterns in rotating systems are investigated within the framework of modified Swift-Hohenberg equations that can be considered as simple models for rotating convection with broken up-down symmetry, e.g.…
This paper presents a numerical study over a wide parameter space of the likelihood of the dynamical bar-mode instability in differentially rotating magnetized neutron stars. The innovative aspect of this study is the incorporation of…
We discuss the stability and construct dynamical configurations describing the gravitational collapse of unstable neutron stars with realistic equations of state compatible with the recent LIGO-Virgo constraints. Unlike other works that…
We study gravitational instability and consequent star formation in a wide range of isolated disk galaxies, using three-dimensional, smoothed particle hydrodynamics simulations at resolution sufficient to fully resolve gravitational…
Binary neutron star mergers produce massive, hot, rapidly differentially rotating neutron star remnants; electromagnetic and gravitational wave signals associated with the subsequent evolution depend on the stability of these remnants.…
Sources of high frequency gravitational waves are reviewed. Gravitational collapse, rotational instabilities and oscillations of the remnant compact objects are potentially important sources of gravitational waves. Significant and unique…