相关论文: The Levi-Civita spacetime

We provide a covariant framework to study singularity-free Lema\^itre-Tolman-Bondi spacetimes with effective corrections motivated by loop quantum gravity. We show that, as in general relativity, physically reasonable energy distributions…

We have analized a sample of 327 clusters of galaxies spanning the range 0.06-0.70 in redshift. Strong constraints on their mean intracluster emission by dust have been obtained using maps and catalogs from the HERSCHEL HerMES project;…

Starting from the solution of the Einstein field equations in a static and spherically symmetric spacetime which contains an isotropic fluid, we construct a model to represent the interior of compact objects with compactness rate…

The Einstein equations with a positive cosmological constant are coupled to the pressureless perfect fluid matter in plane symmetry. Under suitable restrictions on the initial data, the resulting Einstein-dust system is proved to have a…

We aim at constraining the dust mass in high-redshift ($z\gtrsim 5$) galaxies using the upper limits obtained by ALMA in combination with the rest-frame UV--optical spectral energy distributions (SEDs). For SED fitting, because of…

We revisit the interpretation of the cylindrically symmetric, static vacuum Levi-Civita metric, known in either Weyl, Einstein-Rosen, or Kasner-like coordinates. Despite the infinite axis source, we derive its Komar mass density through a…

The coupling of the metric to an incoherent dust introduces into spacetime a privileged dynamical reference frame and time foliation. The comoving coordinates of the dust particles and the proper time along the dust worldlines become…

If galaxy clusters contain intracluster dust, the spectra of galaxies lying behind clusters should show attenuation by dust absorption. We compare the optical (3500 - 7200 \AA) spectra of 60,267 luminous, early-type galaxies selected from…

We find a class of exact solutions of differentially rotating dust in the framework of General Relativity. There exist asymptotically flat space-times of the flow with positive mass function that for radii sufficiently large is monotonic…

We examine the gravitational collapse of an infinite cylindrical distribution of time like dust. In order to simplify the calculation we make an assumption that the axial and azimuthal metric functions are equal. It is shown that the…

The exact global solution of the Einstein equations [Neugebauer & Meinel, Phys. Rev. Lett. 75 (1995) 3046] describing a rigidly rotating, self-gravitating disk is discussed. The underlying matter model is a perfect fluid in the limit of…

A new vision of the beginning and expansion of our universe has produced a solution to the vacuum energy problem (also known as "cosmological constant problem"). A new dynamic of cellular spaces and a discrete time has space being produced…

We consider 4-dimensional spacetime manifolds that are piecewise Lorentzian, where the Lorentzian components of the manifold are separated by codimension-one planes (spacelike or timelike) on which the metric is degenerate. Such manifolds…

In this article, a special static spherically symmetric perfect fluid solution of Einstein's equations is provided. Though pressure and density both diverge at the origin, their ratio remains constant. The solution presented here fails to…

The existence of stationary bound states for the hydrodynamic velocity field between two concentric cylinders is established. We argue that rotational motion, together with a trapping mechanism for the associated field, is sufficient to…

Energy positivity is established for a class of solutions to Einstein-aether theory and the IR limit of Ho\v{r}ava gravity within a certain range of coupling parameters. The class consists of solutions where the aether 4-vector is…

In this paper we present a class of exact inhomogeneous solutions to Einstein's equations for higher dimensional Szekeres metric with perfect fluid and a cosmological constant. We also show particular solutions depending on the choices of…

The local and global properties of the Levi-Civita (LC) solutions coupled with an electromagnetic field are studied and some limits to the vacuum LC solutions are given. By doing such limits, the physical and geometrical interpretations of…

The self-gravitating gas in the presence of a positive cosmological constant Lambda is studied in thermal equilibrium by Monte Carlo simulations and by the mean field approach. We find excellent agreement between both approaches already for…

We introduce a novel class of field theories where energy always flows along timelike geodesics, mimicking in that respect dust, yet which possess non-zero pressure. This theory comprises two scalar fields, one of which is a Lagrange…