Related papers: Static and Dynamic Melvin Universes
The amplitude of jet distortions and accompanying pressure and velocity fluctuations resulting from Kelvin-Helmholtz instability of three dimensional relativistic jets are explored. The effect of instability on jets as they accelerate from…
We perform nonlinear general relativistic ideal magnetohydrodynamic simulations of poloidal magnetic fields in rotating polytropic neutron stars. We have three primary goals: i) to understand the nature of magnetohydrodynamic instabilities…
In this article, I introduce ideas and techniques to extract information about the equation of state of matter at very high densities from gravitational waves emitted before, during and after the merger of binary neutron stars. I also…
This chapter reviews theoretical work on the stellar dynamics of galaxy disks. All the known collective global instabilities are identified, and their mechanisms described in terms of local wave mechanics. A detailed discussion of warps and…
We extend the Kelvin-Helmholtz instability to an expanding background. We study the evolution of a non-viscous irrotational fluid and find that for wavelengths much smaller than the Hubble scale small perturbations of the fluid are unstable…
We study a collapsing system attracted by a spherically symmetric gravitational source, with an increasing mass, that generates back-reaction effects that are the source of space-time waves. As an example, we consider an exponential…
Astronomical observations are suggesting that the fine structure constant varies cosmologically. We present an analysis on the consequences that these variations might induce on the electromagnetic field as a whole. We show that under these…
In this article we present an exact and unified description of wave-packet dynamics in various 2D systems in presence of a transverse magnetic field. We consider an initial minimum-uncertainty Gaussian wave-packet, and find that its long…
Massive gravity is a modified theory of general relativity. In this paper, we study, using a method in which the scale factor changes as a particle in a "potential", all possible cosmic evolutions in a ghost-free massive gravity. We find…
An oscillating, compact Friedmann universe with a massive conformally coupled scalar field is studied in the framework of quantum cosmology. The scalar field is treated as a perturbation and we look for solutions of the Wheeler-DeWitt…
We review sources of high-frequency gravitational waves, summarizing our current understanding of emission mechanisms, expected amplitudes and event rates. The most promising sources are gravitational collapse (formation of black holes or…
In the case of the energy-momentum tensor related to "ordinary" matter (perfect fluid representing spin 1/2 and 1 fields), the equations of general relativity result in cosmological and gravitational collapse singularities--due to the…
With the arrival of the era of gravitational wave astronomy, the strong gravitational field regime will be explored soon in various aspects. In this article, we provide a general review over cylindrical systems in Einstein's theory of…
Starting from the assumption that general relativity might be an emergent phenomenon showing up at low-energies from an underlying microscopic structure, we re-analyze the stability of a static closed Universe filled with radiation. In this…
An exact analytical model of the process of collision and nonlinear interaction of gravitational and/or electromagnetic soliton wave and strong non-soliton electromagnetic traveling wave of arbitrary profile propagating in the expanding…
We study the gravitational collapse of a dust dark matter star in a $\Lambda$-background. We consider two distinct cases: First we do not have a dark matter and dark energy coupling; second, we consider that $\Lambda $ decay in dark…
A model for a possible variable cosmic object is presented. The model consists of a massive shell surrounding a compact object. The gravitational and self-gravitational forces tend to collapse the shell, but the internal tangential stresses…
Within the closed universe, we obtain the amplitude and frequency of gravitational waves in the terms of discrete wave numbers, wave propagation time, and cosmological constant using the deviation equation in the first-order perturbed…
We study the fate of gravitational collapse in presence of a cosmological constant. The junctions conditions between static and non-static space-times are deduced. Three apparent horizon are formed, but only two have physical significance,…
The junction conditions between static and non-static space-times are studied for analyzing gravitational collapse in the presence of a cosmological constant. We have discussed about the apparent horizon and their physical significance. We…