0 Gravitational Collapse and Cosmological Constant
نویسنده
چکیده
We consider here the effects of a non-vanishing cosmological term on the final fate of a spherical inhomogeneous collapsing dust cloud. It is shown that depending on the nature of the initial data from which the collapse evolves, and for a positive value of the cosmological constant, we can have a globally regular evolution where a bounce develops within the cloud. We characterize precisely the initial data causing such a bounce in terms of the initial density and velocity profiles for the collapsing cloud. In the cases otherwise, the result of collapse is either formation of a black hole or a naked singularity resulting as the end state of collapse. We also show here that a positive cosmological term can cover a part of the singularity spectrum which is visible in the corresponding dust collapse models for the same initial data.
منابع مشابه
Gravitational Perfect Fluid Collapse With Cosmological Constant
In this paper, the effect of a positive cosmological constant on spherically symmetric collapse with perfect fluid has been investigated. The matching conditions between static exterior and non-static interior spacetimes are given in the presence of a cosmological constant. We also study the apparent horizons and their physical significance. It is concluded that the cosmological constant slows ...
متن کاملGravitational Dust Collapse with Cosmological Constant
In this paper, we study the effect of a positive cosmological constant on spherically symmetric dust collapse. We take the FRW metric in the interior region whereas Schwarzschild-de Sitter in the exterior region. The matching conditions between exterior and interior spacetimes are given in the presence of a cosmological constant. We also discuss the apparent horizons and their physical signific...
متن کاملMatching Conditions and Gravitational Collapse in Two-Dimensional Gravity
The general theory of matching conditions is developed for gravitational theories in two spacetime dimensions. Models inspired from general relativity and from string theory are considered. These conditions are used to study collapsing dust solutions in spacetimes with non-zero cosmological constant, demonstrating how two-dimensional black holes can arise as the endpoint of such collapse proces...
متن کاملRelativistic fluid spheres with particular application in cosmology and gravitational collapse
A spherically symmetric comoving fluid solution of Einstein’s equations is adapted for cosmological application by extending the geometry of standard FRW cosmology using a generalised curvature term. The resulting model retains many of the known cosmological properties including homogeneity of energy density, its relationship with internal pressure including equations of state, although in each...
متن کامل2 v 1 2 6 A pr 1 99 2 Gravitational Lensing and the Variability of G
The four observables associated with gravitational lensing of distant quasars by intervening galaxies: image splittings, relative amplifications, time delays, and optical depths, provide separate measures of the strength of the gravitational constant G at cosmological distances. These allow one, in principle, to factor out unknown lensing parameters to directly to probe the variation of G over ...
متن کامل