Relativistic Gravitational Collapse of a Cylindrical Shell of Dust

Abstract

The gravitational collapse of a thick cylindrical shell of dust matter is investigated. It is found that a spacetime singularity forms on the symmetry axis and that it is necessarily naked, i.e., observable in principle. We propose a physically reasonable boundary condition at this naked singularity to construct the solution including its causal future. This boundary condition enables us to construct the unique continuation of spacetime beyond the naked singularity and ensures that the dust shell passes through the naked singularity. When the cylindrical shell leaves its symmetry axis away, the naked singularity disappears, and regularity is recovered. We construct numerical solutions with this feature. This result implies that the gravity produced by a thick cylindrical shell of dust is too weak to bind the shell even if it engenders the formation of a curvature singularity which is so strong as to satisfy the limiting focusing condition. For this reason, this naked singularity is very weak in the extended spacetime; the metric tensor is $C^{1-}$ even at the naked singularity, and the extended spacetime is complete for almost all geodesics. This feature is also seen for singular hypersurfaces. Such an extended spacetime can be regarded as phenomenological in the sense that it is valid if the relevant microphysics length scale is sufficiently small compared to the scale of interest.

arXiv comment32 pages, 6 figures

References in corpus (10)

• Naked Singularities in Spherically Symmetric Inhomogeneous Tolman-Bondi Dust Cloud Collapse
• Gravitational waves, black holes and cosmic strings in cylindrical symmetry
• Naked strong curvature singularities in Szekeres space-times
• Naked singularities in cylindrical collapse of counter-rotating dust shells
• Non-radial null geodesics in spherical dust collapse
• Birth of timelike naked singularity
• Geometry and topology of singularities in spherical dust collapse
• How Does Naked Singularity Look?
• Naked singularity resolution in cylindrical collapse
• Appearance of the central singularity in spherical collapse

Cited by in corpus (7)

• Spherical gravitational collapse in N-dimensions
• Cylindrical Systems in General Relativity
• Einstein-Rosen waves and the self-similarity hypothesis in cylindrical symmetry
• A cylindrically symmetric, static anisotropic fluid spacetime and the naked singularity
• Nonlinear evolution of cylindrical gravitational waves: numerical method and physical aspects
• Cylindrically symmetric inhomogeneous dust collapse with a zero expansion component
• Exact solutions for spherically gravitational collapse around a black hole: the effect of tangential pressure