Gravitational collapse in (n+2) dimensional quasi-spherical space-time is studied for a fluid with non vanishing radial pressure. An exact analytic solution is obtained (ignoring the arbitrary integration function) for the equation of state pr = (γ − 1)ρ. The singularity is studied locally by comparing the time of formation of apparent horizon and the central shell focusing singularity while th...

The angular momentum of galaxies is routinely ascribed to a process of tidal torques acting during the early stages of gravitational collapse, and is predicted from the initial mass distribution using second-order perturbation theory and the Zel’dovich approximation. We have tested this theory for a flat hierarchical cosmogony using a large N -body simulation with sufficient dynamic range to in...

recently, two of the authors have introduced the collapse capacity spectrummethodology, which allows the assessment of the collapse capacity of highly inelastic p-deltasensitive regular frame structures without performing non-linear time-history analyses. the mainingredient of this method is the collapse capacity spectrum, which represents the seismic collapsecapacity of an inelastic non-deteri...

The gravitational collapse of spherical, barotropic perfect fluids is analyzed here. For the first time, the final state of these systems is studied without resorting to simplifying assumptions such as self-similarity using a new approach based on non-linear o.d.e. techniques, and formation of naked singularities is shown to occur for solutions such that the mass function is analytic in a neigh...

The breaking of an approximate discrete symmetry, the final stages of a first order phase transition, or a postinflationary biased probability distribution for scalar fields are possible cosmological scenarios characterized by the presence of unstable domain wall networks. Combining analytical and numerical techniques, we show that the non-spherical collapse of these domains can be a powerful s...

We consider a general non-linear sigma model coupled to Einstein gravity and show that in spherical symmetry and for a simple realization of self-similarity, the spacetime can be completely determined. We also examine some more specific matter models and discuss their relation to critical collapse. ∗Electronic Address: [email protected] †On leave from Departamento de F́ısica Teórica, U...