S. Kloster

TL;DR: In this paper, Cattoen et al. studied the gravitational vacuum star (gravastar) configuration in a model where the interior de Sitter spacetime segment is continuously extended to the exterior Schwarzschild spacetime, and the multilayered structure of Mazur and Mottola was replaced by a continuous stress energy tensor at the price of introducing anisotropy in the (fluid) model of the gravastar.

TL;DR: In this paper, the authors construct the phase space of isolated horizons with genus greater than 0 and find that the leading term agrees with the A/4 law and the sub-leading contribution is modified by the genus cycles.

TL;DR: In this paper, an ansatz for the equation of state connecting the radial $p r$ and tangential $p t$ pressure was proposed and a non-homogeneous energy/fluid density was obtained which satisfied the conditions expected for an anisotropic gravastar.

TL;DR: In this article, it was shown from the field equations that a body admitting an arbitrary symmetry must satisfy an integral condition analogous to the equilibrium criterion, and it was proved that the vanishing of the scalar curvature of the associated space implies the flatness of the space-time metric.

TL;DR: In this article, the system consisting of a self gravitating perfect fluid and scalar field is considered in detail, and the scalar fields considered are the quintessence and tachyonic forms which have important application in cosmology.