Cosmic spherical void via coarse-graining and averaging non-spherical structures

Abstract

Inhomogeneous cosmological models are able to fit cosmological observations without dark energy under the assumption that we live close to the "center" of a very large-scale under-dense region. Most studies fitting observations by means of inhomogeneities also assume spherical symmetry, and thus being at (or very near) the center may imply being located at a very special and unlikely observation point. We argue that such spherical voids should be treated only as a gross first approximation to configurations that follow from a suitable smoothing out of the non-spherical part of the inhomogeneities on angular scales. In this Letter we present a toy construction that supports the above statement. The construction uses parts of the Szekeres model, which is inhomogeneous and anisotropic thus it also addresses the limitations of spherical inhomogeneities. By using the thin-shell approximation (which means that the Israel-Darmois continuity conditions are not fulfilled between the shells) we construct a model of evolving cosmic structures, containing several elongated supercluster-like structures with underdense regions between them, which altogether provides a reasonable coarse-grained description of cosmic structures. While this configuration is not spherically symmetric, its proper volume average yields a spherical void profile of 250 Mpc that roughly agrees with observations. Also, by considering a non-spherical inhomogeneity, the definition of a "center" location becomes more nuanced, and thus the constraints placed by fitting observations on our position with respect to this location become less restrictive.

6 pages, 5 figures, accepted for publication in Phys. Lett. B

References in corpus (20)

• Dark Energy from structure: a status report
• An inhomogeneous alternative to dark energy?
• Confronting Lemaitre-Tolman-Bondi models with Observational Cosmology
• Local Voids as the Origin of Large-angle Cosmic Microwave Background Anomalies I
• POTENT Reconstruction from Mark III Velocities
• Local Voids as the Origin of Large-angle Cosmic Microwave Background Anomalies: The Effect of a Cosmological Constant
• The supernova Hubble diagram for off-center observers in a spherically symmetric inhomogeneous universe
• Szekeres Swiss-Cheese model and supernova observations
• Local Void vs Dark Energy: Confrontation with WMAP and Type Ia Supernovae
• You Can't Get Through Szekeres Wormholes - or - Regularity, Topology and Causality in Quasi-Spherical Szekeres Models
• Testing the Copernican Principle via Cosmological Observations
• Structure formation in the quasispherical Szekeres model
• Evolution of cosmic structures in different environments in the quasispherical Szekeres model
• Dark Energy or Apparent Acceleration Due to a Relativistic Cosmological Model More Complex than FLRW?
• Luminosity distance and redshift in the Szekeres inhomogeneous cosmological models
• Redshift propagation equations in the ${\beta }^{\prime }\ne 0$ Szekeres models
• The Averaging Problem in Cosmology and Macroscopic Gravity
• Physical and Geometrical Interpretation of the epsilon <= 0 Szekeres Models
• Geometry and topology of the quasi-plane Szekeres model
• Volume averaging in the quasispherical Szekeres model

Cited by in corpus (41)

• Inhomogeneous cosmological models: exact solutions and their applications
• Observational constraints on inhomogeneous cosmological models without dark energy
• Inhomogeneity effects in Cosmology
• A novel approach to the dynamics of Szekeres dust models
• Back-reaction and effective acceleration in generic LTB dust models
• Differential cosmic expansion and the Hubble flow anisotropy
• Statistics of cosmic density profiles from perturbation theory
• Exploring the evidence for a large local void with supernovae Ia data
• Redshift propagation equations in the ${\beta }^{\prime }\ne 0$ Szekeres models
• Inhomogeneous cosmology and backreaction: Current status and future prospects
• Vorticity and entropy production in tilted Szekeres spacetimes
• Multiple non-spherical structures from the extrema of Szekeres scalars
• The KBC Void: Consistency with Supernovae Type Ia and the Kinematic SZ Effect in a $\Lambda$LTB Model
• Redshift drift in axially symmetric quasi-spherical Szekeres models
• Large-scale growth evolution in the Szekeres inhomogeneous cosmological models with comparison to growth data
• Testing for a large local void by investigating the Near-Infrared Galaxy Luminosity Function
• Coarse-grained description of cosmic structure from Szekeres models
• Effect of inhomogeneities on high precision measurements of cosmological distances
• Some clarifications about Lemaître-Tolman models of the Universe used to deal with the dark energy problem
• Non-Spherical Szekeres models in the language of Cosmological Perturbations
• Apparent horizons in the quasi-spherical Szekeres models
• Constructing Realistic Szekeres Models from Initial and Final Data
• Accelerating expansion or inhomogeneity? A comparison of the $\Lambda$CDM and Lema\^ıtre - Tolman models
• CMB dipoles and other low-order multipoles in the quasispherical Szekeres model
• Symmetry and Equivalence in Szekeres Models
• Testing the Copernican Principle with Hubble Parameter
• On the role of shear in cosmological averaging II: large voids, non-empty voids and a network of different voids
• Lagrangian theory of structure formation in relativistic cosmology. VI. Comparison with Szekeres exact solutions
• Non-comoving Cold Dark Matter in a $\Lambda$CDM background
• Thermodynamics and Lemaitre-Tolman-Bondi void models
• Frame Rotation in the Szekeres Spacetimes
• On the physical effects of consistent cosmological averaging
• Black hole formation from the gravitational collapse of a non-spherical network of structures
• Physical geometry of the quasispherical Szekeres models
• Non-comoving baryons and cold dark matter in cosmic voids
• Pancakes as opposed to Swiss Cheese
• On general-relativistic Lagrangian perturbation theory and its non-perturbative generalization
• Expansion and Growth of Structure Observables in a Macroscopic Gravity Averaged Universe
• Beyond relativistic Lagrangian perturbation theory. I. An exact-solution controlled model for structure formation
• Rotation, Embedding and Topology for the Szekeres Geometry
• Supernovae as cosmological probes