Simple inhomogeneous cosmological (toy) models

Abstract

Based on the Lemaître-Tolman-Bondi (LTB) metric we consider two flat inhomogeneous big-bang models. We aim at clarifying, as far as possible analytically, basic features of the dynamics of the simplest inhomogeneous models and to point out the potential usefulness of exact inhomogeneous solutions as generalizations of the homogeneous configurations of the cosmological standard model. We discuss explicitly partial successes but also potential pitfalls of these simplest models. Although primarily seen as toy models, the relevant free parameters are fixed by best-fit values using the Joint Light-curve Analysis (JLA)-sample data. On the basis of a likelihood analysis we find that a local hump with an extension of almost 2 Gpc provides a better description of the observations than a local void for which we obtain a best-fit scale of about 30 Mpc. Future redshift-drift measurements are discussed as a promising tool to discriminate between inhomogeneous configurations and the $\Lambda$CDM model.

arXiv comment30 pages, 14 figures, comments and references added, accepted for publication in JCAP

References in corpus (20)

• Observational Evidence from Supernovae for an Accelerating Universe and a Cosmological Constant
• Measurements of Omega and Lambda from 42 High-Redshift Supernovae
• Improved cosmological constraints from a joint analysis of the SDSS-II and SNLS supernova samples
• Evidence for a ~300 Mpc Scale Under-density in the Local Galaxy Distribution
• Do we really see a cosmological constant in the supernovae data ?
• Large Scale Inhomogeneity Versus Source Evolution -- Can We Distinguish Them Observationally?
• Is dark energy the only solution to the apparent acceleration of the present universe?
• Observational Challenges for the Standard FLRW Model
• Observational constraints on inhomogeneous cosmological models without dark energy
• A (giant) void is not mandatory to explain away dark energy with a Lemaitre - Tolman model
• Distances and lensing in cosmological void models
• The kSZ effect as a test of general radial inhomogeneity in LTB cosmology
• Redshift Drift in LTB Void Universes
• Can decaying modes save void models for acceleration?
• Redshift drift in an inhomogeneous universe: averaging and the backreaction conjecture
• Some clarifications about Lemaître-Tolman models of the Universe used to deal with the dark energy problem
• Accelerating expansion or inhomogeneity? A comparison of the $\Lambda$CDM and Lema\^ıtre - Tolman models
• Obscured clusters.IV. The most massive stars in [DBS2003]179
• Type Ia supernova parameter estimation: a comparison of two approaches using current datasets
• Blueshifts in the Lema\^ıtre -- Tolman models

Cited by in corpus (3)

• The KBC Void: Consistency with Supernovae Type Ia and the Kinematic SZ Effect in a $\Lambda$LTB Model
• Averaged Lemaître-Tolman-Bondi dynamics
• Alleviating the Hubble Tension with a Local Void and Transitions of the Absolute Magnitude