179 citations · 465 across the 21 of their papers we have counts for
21 papers
Expansion of bundles of light rays in the Lemaître -- Tolman models
Andrzej Krasiński
The locus of for bundles of light rays emitted at noncentral points is investigated for Lema\^ıtre -- Tolman (L--T) models. The three loci that coincide for…
Gamma radiation from areal radius minima in a quasi-spherical Szekeres metric
Andrzej Krasiński
In previous papers it was shown that in a quasi-spherical Szekeres (QSS) metric, impulses of gamma radiation can arise that have several properties in common with the observed gamm…
Short-lived flashes of gamma radiation in a quasi-spherical Szekeres metric
Andrzej Krasiński
In previous papers it was shown that gamma rays with characteristics similar to those of the gamma-ray bursts (GRBs) observed by astronomers may arise from suitably shaped nonunifo…
Properties of blueshifted light rays in quasispherical Szekeres metrics
Andrzej Krasiński
This paper is a follow-up on two previous ones, in which properties of blueshifted rays were investigated in Lema\^ıtre - Tolman (L-T) and quasispherical Szekeres (QSS) spacetimes.…
Existence of blueshifts in quasi-spherical Szekeres spacetimes
Andrzej Krasiński
In Lema\^ıtre -- Tolman (L--T) models, light rays emitted \textit{radially} at the Big Bang (BB) at such radial coordinates where the bang-time function has $\dril {t_…
Cosmological blueshifting may explain the gamma ray bursts
Andrzej Krasiński
It is shown that the basic observed properties of the gamma-ray bursts (GRBs) are accounted for if one assumes that the GRBs arise by blueshifting the emission radiation of hydroge…
Gamma ray bursts may be blueshifted bundles of the relic radiation
Andrzej Krasiński
A hypothesis is proposed that the gamma-ray bursts (GRBs) may arise by blueshifting the emission radiation of hydrogen and helium generated during the last scattering epoch. The bl…
Blueshifts in the Lema\^ıtre -- Tolman models
Andrzej Krasiński
In the Lema\^ıtre -- Tolman (L--T) models that have nonconstant bang-time function , light emitted close to those points of the Big Bang where $\dril {t_B} r \neq 0$ is blu…
Mimicking acceleration in the constant-bang-time Lema\^ıtre -- Tolman model: Shell crossings, density distributions and light cones
Andrzej Krasiński
The Lema\^ıtre -- Tolman model with and constant bang time that imitates the luminosity distance -- redshift relation of the CDM model using the energy function alone…
Accelerating expansion or inhomogeneity? Part 2: Mimicking acceleration with the energy function in the Lema\^ıtre-Tolman model
Andrzej Krasiński
This is a continuation of the paper published in {\it Phys. Rev.} {\bf D89}, 023520 (2014). It is investigated here how the luminosity distance -- redshift relation of the…
Accelerating expansion or inhomogeneity? A comparison of the CDM and Lema\^ıtre - Tolman models
Andrzej Krasiński
It is shown how certain observations interpreted in the background of the Friedmann model with (the CDM model) can be re-interpreted using the Lema\^ıtre - Tol…
Exact inhomogeneous models and the drift of light rays induced by nonsymmetric flow of the cosmic medium
Andrzej Krasiński, Krzysztof Bolejko
After introducing the Szekeres and Lema\^ıtre--Tolman cosmological models, the real-time cosmology program is briefly mentioned. Then, a few widespread misconceptions about the cos…
Geometry of the quasi-hyperbolic Szekeres models
Andrzej Krasiński, Krzysztof Bolejko
Geometric properties of the quasi-hyperbolic Szekeres models are discussed and related to the quasi-spherical Szekeres models. Typical examples of shapes of various classes of 2-di…
Repeatable light paths in the conformally flat cosmological models
Andrzej Krasiński
This is a supplement to an earlier paper (PRD 84, 023510 (2011)), where those shearfree normal cosmological models were identified, in which all light rays have repeatable paths. A…
Apparent horizons in the quasi-spherical Szekeres models
Andrzej Krasiński, Krzysztof Bolejko
The notion of an apparent horizon (AH) in a collapsing object can be carried over from the Lema\^ıtre -- Tolman (L--T) to the quasispherical Szekeres models in three ways: 1. Liter…
Repeatable light paths in the shearfree normal cosmological models
Andrzej Krasiński
Conditions for the existence of repeatable light paths (RLPs) in the shearfree normal cosmological models are investigated. It is found that in the conformally nonflat models the o…
Inhomogeneous cosmological models: exact solutions and their applications
Krzysztof Bolejko, Marie-Noëlle Célérier, Andrzej Krasiński
Recently, inhomogeneous generalisations of the Friedmann-Lemaitre-Robertson-Walker cosmological models have gained interest in the astrophysical community and are more often employ…
Redshift propagation equations in the Szekeres models
Andrzej Krasiński, Krzysztof Bolejko
The set of differential equations obeyed by the redshift in the general Szekeres spacetimes is derived. Transversal components of the ray's momentum have to be taken in…
A (giant) void is not mandatory to explain away dark energy with a Lemaitre - Tolman model
Marie-Noëlle Célérier, Krzysztof Bolejko, Andrzej Krasiński
Lemaître - Tolman (L--T) toy models with a central observer have been used to study the effect of large scale inhomogeneities on the SN Ia dimming. Claims that a giant void is mand…
Geometry and topology of the quasi-plane Szekeres model
Andrzej Krasiński
This paper is a revised version of arXiv:0805.0529 and Phys.Rev. D78, 064038 (2008), taking into account the erratum published in Phys.Rev. D85, 069903(E) (2012). Geometrical and t…
Can a charged dust ball be sent through the Reissner--Nordström wormhole?
Andrzej Krasiński, Krzysztof Bolejko
In a previous paper we formulated a set of necessary conditions for the spherically symmetric weakly charged dust to avoid Big Bang/Big Crunch, shell crossing and permanent central…