Trapped surfaces in prolate collapse in the Gibbons-Penrose construction

Abstract

We investigate existence and properties of trapped surfaces in two models of collapsing null dust shells within the Gibbons-Penrose construction. In the first model, the shell is initially a prolate spheroid, and the resulting singularity forms at the ends first (relative to a natural time slicing by flat hyperplanes), in analogy with behavior found in certain prolate collapse examples considered by Shapiro and Teukolsky. We give an explicit example in which trapped surfaces are present on the shell, but none exist prior to the last flat slice, thereby explicitly showing that the absence of trapped surfaces on a particular, natural slicing does not imply an absence of trapped surfaces in the spacetime. We then examine a model considered by Barrabes, Israel and Letelier (BIL) of a cylindrical shell of mass M and length L, with hemispherical endcaps of mass m. We obtain a "phase diagram" for the presence of trapped surfaces on the shell with respect to essential parameters $\lambda \equiv M/L$ and $\mu \equiv m/M$. It is found that no trapped surfaces are present on the shell when $\lambda$ or $\mu$ are sufficiently small. (We are able only to search for trapped surfaces lying on the shell itself.) In the limit $\lambda \to 0$, the existence or nonexistence of trapped surfaces lying within the shell is seen to be in remarkably good accord with the hoop conjecture.

22 pages, 6 figures

References in corpus (1)

• Collapsing Shells and the Isoperimetric Inequality for Black Holes

Cited by in corpus (14)

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• Numerical Approaches to Spacetime Singularities
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• Formation of naked singularities in five-dimensional space-time
• Naked Singularities in Higher Dimensional Szekeres Space-time
• Geometry of normal graphs in Euclidean space and applications to the Penrose inequality in Minkowski
• Collapse Geometry in Inhomogeneous FRW model
• Role of Initial Data in Higher Dimensional Quasi-Spherical Gravitational Collapse
• No-horizon theorem for spacetimes with spacelike G1 isometry groups
• Prolate horizons and the Penrose inequality
• No-horizon theorem for vacuum gravity with spacelike G1 isometry groups