157 citations · 309 across the 20 of their papers we have counts for
23 papers
Relativistic models of structure formation with stable end-state configuration
Jan J. Ostrowski
The aim of this paper is to provide an analytical model for the formation of stable structures (cosmological or astrophysical), where stability is obtained through the tangential p…
The model of the local Universe in the framework of the second-order perturbation theory
Szymon Sikora, Jan J. Ostrowski
Recently, we constructed the specific solution to the second-order cosmological perturbation theory, around any Friedmann-Lemaitre-Robertson-Walker (FLRW) background filled with du…
Relativistic modeling of cosmological structures with Bianchi IX spacetimes
Przemyslaw Malkiewicz, Jan J. Ostrowski, Ismael Delgado Gaspar
We develop a relativistic framework to investigate the evolution of cosmological structures from the initial density perturbations to the highly nonlinear regime. Our approach invo…
Quantum system ascribed to the Oppenheimer-Snyder model of massive star
A. Góźdź, J. J. Ostrowski, A. Pȩdrak +1
We quantize the Oppenheimer-Snyder model of black hole using the integral quantization method. We treat spatial and temporal coordinates on the same footing both at classical and q…
Beyond relativistic Lagrangian perturbation theory. I. An exact-solution controlled model for structure formation
Ismael Delgado Gaspar, Thomas Buchert, Jan J. Ostrowski
We develop a new nonlinear method to model structure formation in general relativity from a generalization of the relativistic Lagrangian perturbation schemes, controlled by Szeker…
On general-relativistic Lagrangian perturbation theory and its non-perturbative generalization
Thomas Buchert, Ismael Delgado Gaspar, Jan J. Ostrowski
The Newtonian Lagrangian perturbation theory is a widely used framework to study structure formation in cosmology in the nonlinear regime. We review a general-relativistic formulat…
On the maximum volume of collapsing structures
Jan J. Ostrowski, Ismael Delgado Gaspar
In many cosmological models, including the CDM concordance model, there exist a theoretical upper bounds on the size of collapsing structures. The most common formulations in th…
Hamiltonian formulation of dust cloud collapse
Nick Kwidzinski, Daniele Malafarina, Jan Ostrowski +2
We consider the gravitational collapse of self-gravitating spherical dust cloud in the Hamiltonian formalism. We address both homogeneous and inhomogeneous cases. Our novel derivat…
A few numbers from the turnaround epoch of collapse
Jan J. Ostrowski
The turnaround epoch of gravitational collapse is examined by means of relativistic Lagrangian perturbation theory. Averaged, scalar equations applied to the fluid's evolution reve…
Does spatial flatness forbid the turnaround epoch of collapsing structures?
Boudewijn F. Roukema, Jan J. Ostrowski
Cosmological observational analysis frequently assumes that the Universe is spatially flat. We aim to non-perturbatively check the conditions under which a flat or nearly flat expa…
The environment-dependence of the growth of the most massive objects in the Universe
Krzysztof Bolejko, Jan J. Ostrowski
This paper investigates the growth of the most massive cosmological objects. We utilize the Simsilun simulation, which is based on the approximation of the silent universe. In the…
Order-unity argument for structure-generated "extra" expansion
Boudewijn F. Roukema, Jan J. Ostrowski, Thomas Buchert +1
Self-consistent treatment of cosmological structure formation and expansion within the context of classical general relativity may lead to "extra" expansion above that expected in…
Mass function of galaxy clusters in relativistic inhomogeneous cosmology
Jan J. Ostrowski, Thomas Buchert, Boudewijn F. Roukema
The current cosmological model (CDM) with the underlying FLRW metric relies on the assumption of local isotropy, hence homogeneity of the Universe. Difficulties arise when one a…
The background Friedmannian Hubble constant in relativistic inhomogeneous cosmology and the age of the Universe
Boudewijn F. Roukema, Pierre Mourier, Thomas Buchert +1
In relativistic inhomogeneous cosmology, structure formation couples to average cosmological expansion. A conservative approach to modelling this assumes an Einstein--de Sitter mod…
On the relativistic mass function and averaging in cosmology
Jan J. Ostrowski, Thomas Buchert, Boudewijn F. Roukema
The general relativistic description of cosmological structure formation is an important challenge from both the theoretical and the numerical point of views. In this paper we pres…
On the Green and Wald formalism
Jan J. Ostrowski, Boudewijn F. Roukema
Backreaction in the cosmological context is a longstanding problem that is especially important in the present era of precise cosmology. The standard model of a homogeneous backgro…
Is the baryon acoustic oscillation peak a cosmological standard ruler?
Boudewijn F. Roukema, Thomas Buchert, Hirokazu Fujii +1
In the standard model of cosmology, the Universe is static in comoving coordinates; expansion occurs homogeneously and is represented by a global scale factor. The baryon acoustic…
Is there proof that backreaction of inhomogeneities is irrelevant in cosmology?
T. Buchert, M. Carfora, G. F. R. Ellis +8
No. In a number of papers Green and Wald argue that the standard FLRW model approximates our Universe extremely well on all scales, except close to strong field astrophysical objec…
Evidence for an environment-dependent shift in the baryon acoustic oscillation peak
Boudewijn F. Roukema, Thomas Buchert, Jan J. Ostrowski +1
The Friedmann-Lemaitre-Robertson-Walker (FLRW) metric assumes comoving spatial rigidity of metrical properties. The curvature term in comoving coordinates is environment-independen…
Virialization-induced curvature versus dark energy
Jan J. Ostrowski, Boudewijn F. Roukema, Thomas Buchert
The concordance model is successful in explaining numerous observable phenomena at the price of introducing an exotic source of unknown origin: dark energy. Dark energy dominance o…
Virialisation-induced curvature as a physical explanation for dark energy
Boudewijn F. Roukema, Jan J. Ostrowski, Thomas Buchert
The geometry of the dark energy and cold dark matter dominated cosmological model (LambdaCDM) is commonly assumed to be given by a Friedmann-Lemaitre-Robertson-Walker (FLRW) metric…
Topological implications of inhomogeneity
Boudewijn F. Roukema, Vincent Blanloeil, Jan J. Ostrowski
The approximate homogeneity of spatial sections of the Universe is well supported observationally, but the inhomogeneity of the spatial sections is even better supported. Here, we…
A relativistic model of the topological acceleration effect
Jan J. Ostrowski, Boudewijn F. Roukema, Zbigniew P. Bulinski
It has previously been shown heuristically that the topology of the Universe affects gravity, in the sense that a test particle near a massive object in a multiply connected univer…