Waters, Thomas J., Nolan, Brien C.
In this paper we consider gauge invariant linear perturbations of the metric and matter tensors describing the self-similar Lema\^itre-Tolman-Bondi (timelike dust) spacetime containing a naked...
Einstein-Rosen waves and the self-similarity hypothesis in cylindrical symmetry (2008)
Harada, Tomohiro, Nakao, Ken-ichi, Nolan, Brien C.
The self-similarity hypothesis claims that in classical general relativity spherically symmetric solutions may naturally evolve to a self-similar form in certain circumstances. In this context, the...
Yang's Gravitational Theory (2007)
Brendan S. Guilfoyle, Brien C. Nolan
Yang's pure space equations (C.N. Yang, Phys. Rev. Lett. 33, 445 (1974)) generalize Einstein's gravitational equations, while coming from gauge theory. We study these equations from a...
Wave Tails and the Geometric Optics Approximation (2007)
The effect of the existence of tails on the propagation of scalar waves in curved space-time is considered via an analysis of flux integrals of the energystress-momentum tensor of the waves. The...
Is the shell-focusing singularity of Szekeres space-time visible? (2007)
Nolan, Brien C., Debnath, Ujjal
The visibility of the shell-focusing singularity in Szekeres space-time - which represents quasi-spherical dust collapse - has been studied on numerous occasions in the context of the cosmic...
Odd-parity perturbations of self-similar Vaidya spacetime (2006)
We carry out an analytic study of odd-parity perturbations of the self-similar Vaidya space-times that admit a naked singularity. It is found that an initially finite perturbation remains finite at...
Bounds for scalar waves on self-similar naked-singularity backgrounds (2006)
The stability of naked singularities in self-similar collapse is probed using scalar waves. It is shown that the multipoles of a minimally coupled massless scalar field propagating on a spherically...
Axially symmetric equilibrium regions of Friedmann-Lemaitre-Robertson-Walker universes (2005)
The study of the matching of stationary and axisymmetric spacetimes with Friedmann-Lemaitre-Robertson-Walker spacetimes preserving the axial symmetry is presented. We show, in particular, that any...
Even perturbations of self-similar Vaidya space-time (2005)
Nolan, Brien C., Waters, Thomas J.
We study even parity metric and matter perturbations of all angular modes in self-similar Vaidya space-time. We focus on the case where the background contains a naked singularity. Initial conditions...
On global models for finite rotating objects in equilibrium in cosmological backgrounds (2005)
The studies in general relativity of rotating finite objects in equilibrium have usually focused on the case when they are truly isolated, this is, the models to describe finite objects are embedded...
Physical interpretation of gauge invariant perturbations of spherically symmetric space-times (2004)
By calculating the Newman-Penrose Weyl tensor components of a perturbed spherically symmetric space-time with respect to invariantly defined classes of null tetrads, we give a physical...
The role of anisotropy and inhomogeneity in Lemaitre-Tolman-Bondi collapse (2004)
Mena, Filipe C., Nolan, Brien C., Tavakol, Reza
We study the effects of shear and density inhomogeneities in the formation of naked singularities in spherically symmetric dust space--times. We find that in general neither of these physical...
Dynamical extensions for shell-crossing singularities (2003)
We derive global weak solutions of Einstein's equations for spherically symmetric dust-filled space-times which admit shell-crossing singularities. In the marginally bound case, the solutions are...
Cauchy horizon stability in self-similar collapse: scalar radiation (2002)
Nolan, Brien C, Waters, Thomas J
The stability of the Cauchy horizon in spherically symmetric self-similar collapse is studied by determining the flux of scalar radiation impinging on the horizon. This flux is found to be finite.
Naked singularities in cylindrical collapse of counter-rotating dust shells (2002)
Solutions describing the gravitational collapse of asymptotically flat cylindrical and prolate shells of (null) dust are shown to admit globally naked singularities.
Geometry and topology of singularities in spherical dust collapse (2002)
Nolan, Brien C., Mena, Filipe C.
We derive some more results on the nature of the singularities arising in the collapse of inhomogeneous dust spheres. (i) It is shown that there are future-pointing radial and non-radial time-like...
Nolan, Brien C., Mena, Filipe C.
It has been claimed that the Lemaitre-Tolman-Bondi-de Sitter solution always admits future-pointing radial time-like geodesics emerging from the shell-focussing singularity, regardless of the nature...
Non-radial null geodesics in spherical dust collapse (2001)
Mena, Filipe C, Nolan, Brien C
The issue of the local visibility of the shell-focussing singularity in marginally bound spherical dust collapse is considered from the point of view of the existence of future-directed null...
A note on behaviour at an isotropic singularity (2001)
The behaviour of Jacobi fields along a time-like geodesic running into an isotropic singularity is studied. It is shown that the Jacobi fields are crushed to zero length at a rate which is the same...
Sectors of spherical homothetic collapse (2000)
A study is undertaken of the gravitational collapse of spherically symmetric thick shells admitting a homothetic Killing vector field under the assumption that the energy momentum tensor corresponds...
The Central Singularity in Spherical Collapse (2000)
The gravitational strength of the central singularity in spherically symmetric space-times is investigated. Necessary conditions for the singularity to be gravitationally weak are derived and it is...
A point mass in an isotropic universe: III. The region $R\leq 2m$ (1999)
McVittie's solution of Einstein's field equations, representing a point mass embedded into an isotropic universe, possesses a scalar curvature singularity at proper radius $R=2m$. The singularity is...
A geodesically complete space-time with a crushing null hypersurface (1999)
Withdrawn; conclusion that the singularity is strong is incorrect.
A regular C^0 singularity is not necessarily weak (1999)
Examples of space-times are given which contain scalar curvature singularities whereat the metric tensor is regular and continuous, but which are gravitationally strong. Thus the argument that such...
Strengths of singularities in spherical symmetry (1999)
Covariant equations characterizing the strength of a singularity in spherical symmetry are derived and several models are investigated. The difference between central and non-central singularities is...
A point mass in an isotropic universe. Existence, uniqueness and basic properties (1998)
Criteria which a space-time must satisfy to represent a point mass embedded in an open Robertson--Walker (RW) universe are given. It is shown that McVittie's solution in the case $k=0$ satisfies...
Yang's gravitational theory (1998)
Guilfoyle, Brendan S., Nolan, Brien C.
Yang's pure space equations (C.N. Yang, Phys. Rev. Lett. v.33, p.445 (1974)) generalize Einstein's gravitational equations, while coming from gauge theory. We study these equations from a number of...
A Characterisation of Strong Wave Tails in Curved Space-Times (1997)
A characterisation of when wave tails are strong is proposed. The existence of a curvature induced tail (i.e. a Green's function term whose support includes the interior of the light-cone) is...
An Analysis of Wave Tails based on the Geometric Optics Approximation (1996)
The effect of the existence of tails on the propagation of scalar waves in curved space-time is considered via an analysis of flux integrals of the energy-stress-momentum tensor of the waves. The...
The Goldberg--Kerr Approach to Lorentz Covariant Gravity (1995)
The approach to asymptotic electromagnetic fields introduced by Goldberg and Kerr is used to study various aspects of Lorentz Covariant Gravity. Retarded multipole moments of the source, the central...