CMB observations in LTB universes: Part I: Matching peak positions in the CMB spectrum

Abstract

Acoustic peaks in the spectrum of the cosmic microwave background in spherically symmetric inhomogeneous cosmological models are studied. At the photon-baryon decoupling epoch, the universe may be assumed to be dominated by non-relativistic matter, and thus we may treat radiation as a test field in the universe filled with dust which is described by the Lemaître-Tolman-Bondi (LTB) solution. First, we give an LTB model whose distance-redshift relation agrees with that of the concordance $\Lambda$CDM model in the whole redshift domain and which is well approximated by the Einstein-de Sitter universe at and before decoupling. We determine the decoupling epoch in this LTB universe by Gamow's criterion and then calculate the positions of acoustic peaks. Thus obtained results are not consistent with the WMAP data. However, we find that one can fit the peak positions by appropriately modifying the LTB model, namely, by allowing the deviation of the distance-redshift relation from that of the concordance $\Lambda$CDM model at $z>2$ where no observational data are available at present. Thus there is still a possibility of explaining the apparent accelerated expansion of the universe by inhomogeneity without resorting to dark energy if we abandon the Copernican principle. Even if we do not take this extreme attitude, it also suggests that local, isotropic inhomogeneities around us may seriously affect the determination of the density contents of the universe unless the possible existence of such inhomogeneities is properly taken into account.

20 pages, 5 figures

References in corpus (65)

• Constraints on the redshift dependence of the dark energy potential
• Three-Year Wilkinson Microwave Anisotropy Probe (WMAP) Observations: Temperature Analysis
• A Bitter Pill: The Primordial Lithium Problem Worsens
• An inhomogeneous alternative to dark energy?
• A general test of the Copernican Principle
• CMB Observables and Their Cosmological Implications
• MSSM flat direction inflation: slow roll, stability, fine tunning and reheating
• Confronting Lemaitre-Tolman-Bondi models with Observational Cosmology
• A Local Void and the Accelerating Universe
• A Local Hubble Bubble from SNe Ia?
• Lemaitre-Tolman-Bondi model and accelerating expansion
• Do we really see a cosmological constant in the supernovae data ?
• Time drift of cosmological redshifts as a test of the Copernican principle
• On cosmological observables in a swiss-cheese universe
• Large Scale Inhomogeneity Versus Source Evolution -- Can We Distinguish Them Observationally?
• The effect of inhomogeneous expansion on the supernova observations
• A Test of the Copernican Principle
• CMB anisotropies seen by an off-center observer in a spherically symmetric inhomogeneous universe
• Living in a Void: Testing the Copernican Principle with Distant Supernovae
• Is dark energy the only solution to the apparent acceleration of the present universe?
• Mimicking Dark Energy with Lemaitre-Tolman-Bondi Models: Weak Central Singularities and Critical Points
• An alternative to the cosmological 'concordance model'
• "Swiss-Cheese" Inhomogeneous Cosmology & the Dark Energy Problem
• Looking the void in the eyes - the kSZ effect in LTB models
• Geocentrism reexamined
• Can we avoid dark energy?
• Scalar Perturbations on Lemaitre-Tolman-Bondi Spacetimes
• The supernova Hubble diagram for off-center observers in a spherically symmetric inhomogeneous universe
• Mapping Luminosity-Redshift Relationship to LTB Cosmology
• A (giant) void is not mandatory to explain away dark energy with a Lemaitre - Tolman model
• Analyses of Type Ia Supernova Data in Cosmological Models with a Local Void
• Distances and lensing in cosmological void models
• Local Void vs Dark Energy: Confrontation with WMAP and Type Ia Supernovae
• The Effect of Large-Scale Inhomogeneities on the Luminosity Distance
• The Location of CMB Peaks in a Universe with Dark Energy
• Light Propagation and Large-Scale Inhomogeneities
• The Szekeres Swiss Cheese model and the CMB observations
• Distinguishing Between Void Models and Dark Energy with Cosmic Parallax and Redshift Drift
• The radial BAO scale and Cosmic Shear, a new observable for Inhomogeneous Cosmologies
• Solving the Inverse Problem with Inhomogeneous Universes
• Inhomogeneous spacetimes as a dark energy model
• Bulk flows and CMB dipole anisotropy in cosmological void models
• Testing the Copernican Principle via Cosmological Observations
• Cosmic acceleration: Inhomogeneity versus vacuum energy
• Does the Isotropy of the CMB Imply a Homogeneous Universe? Some Generalised EGS Theorems
• Pressure gradients, shell crossing singularities and acoustic oscillations - application to inhomogeneous cosmological models
• The Hubble Diagram of Type Ia Supernovae in Non-Uniform Pressure Universes
• Supernovae Ia observations in the Lemaitre--Tolman model
• What the small angle CMB really tells us about the curvature of the Universe
• Rendering Dark Energy Void
• Can the Stephani model be an alternative to FRW accelerating models?
• Supernovae data and perturbative deviation from homogeneity
• Luminosity distance-redshift relation for the LTB solution near the center
• Mimicking the cosmological constant for more than one observable with large scale inhomogeneities
• Can the cosmological constant be mimicked by smooth large-scale inhomogeneities for more than one observable?
• Redshift spherical shell energy in isotropic Universes
• Apparent Acceleration through Large-scale Inhomogeneities --Post-Friedmannian Effects of Inhomogeneities on the Luminosity Distance--
• The effect of pressure gradients on luminosity distance - redshift relations
• Anisotropy of the Hubble Constant in a Cosmological Model with a Local Void on Scales of ~ 200 Mpc
• Light-cone observations and cosmological models: implications for inhomogeneous models mimicking dark energy
• Can the Copernican principle be tested by cosmic neutrino background?
• Accelerated cosmic expansion in a scalar-field universe
• Inhomogeneous Cosmology, Inflation and Late-Time Accelerating Universe
• Gauge-invariant treatment of the integrated Sachs-Wolfe effect on general spherically symmetric spacetimes
• The Role of Anisotropy in the Void Models without Dark Energy

Cited by in corpus (28)

• Dark Energy
• Establishing homogeneity of the universe in the shadow of dark energy
• Observational constraints on inhomogeneous cosmological models without dark energy
• Precision cosmology defeats void models for acceleration
• The kSZ effect as a test of general radial inhomogeneity in LTB cosmology
• The Cosmic Microwave Background in an Inhomogeneous Universe - why void models of dark energy are only weakly constrained by the CMB
• Redshift Drift in LTB Void Universes
• Observational constraints on the LLTB model
• Tension in the Void: Cosmic Rulers Strain Inhomogeneous Cosmologies
• Large scale structure simulations of inhomogeneous LTB void models
• Local and non-local measures of acceleration in cosmology
• Exact spherically-symmetric inhomogeneous model with n perfect fluids
• CMB observations in LTB universes: Part II: the kSZ effect in an LTB universe
• Do the observational data favor a local void?
• The effect of inhomogeneities on the distance to the last scattering surface and the accuracy of the CMB analysis
• The Metric of the Cosmos from Luminosity and Age Data
• Do primordial Lithium abundances imply there's no Dark Energy?
• Evolution of density perturbations in large void universe
• Gravitational, shear and matter waves in Kantowski-Sachs cosmologies
• Cosmological Signatures of Anisotropic Spatial Curvature
• Gravitational Waves in Locally Rotationally Symmetric (LRS) Class II Cosmologies
• Tensor Perturbations in Anisotropically Curved Cosmologies
• Physical geometry of the quasispherical Szekeres models
• Two-point correlation function of density perturbations in a large void universe
• Spectral Distortion in a Radially Inhomogeneous Cosmology
• Mimicking acceleration in the constant-bang-time Lema\^ıtre -- Tolman model: Shell crossings, density distributions and light cones
• Systematic error due to isotropic inhomogeneities
• Newtonian self-gravitating system in a relativistic huge void universe model