Abstract By matching across a surface of constant time, it is demon-strated that the spacetime for a radiation-dominated Einstein-de Sitter universe can be directly matched to the spacetime for a matter-dominated Einstein-de Sitter universe. Thus, this can serve as a model of a universe filled

spacetime, unlike previous solutions for cosmological black holes, which violate the energy conditions in some region of spacetime. In addition, it is demonstrated that radiation-dominated and matter-dominated Einstein-de Sitter universes can be directly matched across a hypersurface of constant time

about 1.�2, the true spectral resolution is around 8 Å, consistent with the measured width of the spectral features. The average line profile, constructed from the Fe II lines above 6000 Å, appears unresolved. This implies that the absorbing clouds have a velocity dispersion of less than 100 km s �1 in the rest frame. The observed BATSE gamma-ray fluence of GRB 990123 is 5.09 � 0.02 � 10 –4 erg cm –2 for energies above 20 keV (14). In Table 2 we give the luminosity distance and the inferred isotropic energy output in various cosmologies for z � 1.600. A lower limit to the isotropic energy release in gamma-rays alone is obtained in an

A family of cosmological models is considered which in a certain synchronized system of reference possess flat slices t = const. They are generated from the EINSTEIN-DE SITTER universe by a suitable transformation. Under physically reasonable presumptions these transformed models fulfil certain

dilation factors are also corrected for energy stretching and similar effects. Within an Einstein-de Sitter cosmology, we place strong bounds on the evolution of the bursts, and these bounds are incompatible with a homogeneous population, assuming a power law spectrum and no luminosity evolution

issue of this analysis corresponds to outline the impossibility for the classical origin of density perturbations, due to the exponential decay of the matter term during the de Sitter phase. PACS 98.80.Bp – Origin and formation of the Universe.

-invariant (only geometries appear) and background-independent. The theory can be investigated by computer simulations, which show that a de Sitter universe emerges on large scales. This emergence is of an entropic, self-organizing nature, with the weight of the Einstein-Hilbert action playing a minor role. Also

An analytical model is presented for the postcollapse equilibrium structure of virialized objects which condense out of a low-density cosmological background universe, either matter-dominated or flat with a cosmological constant. This generalizes the model we derived previously for an Einstein-de

Abstract. We consider the quasi-de Sitter geometry of the inflationary universe. We calculate the energy flux of the slowly rolling background scalar field through the quasi-de Sitter apparent horizon and set it equal to the change of the entropy (1/4 of the area) multiplied by the temperature, dE

In the Einstein-de Sitter model, the spherically symmetric less-dense perturbation is in-vestigated with an aim to discuss the observed void in distribution of galaxies. In the nonlinear regime, the enlargement of the perturbed region occurs. For the neutrino dominated model, the enlargement