CMB observations in LTB universes: Part II: the kSZ effect in an LTB universe

Abstract

We study the kinematic Sunyaev-Zel'dovich (kSZ) effect in a Lemître-Tolman-Bondi (LTB) universe model whose distance-redshift relation agrees with that of the concordance $\Lambda$CDM model at redshifts $z\lesssim 2$. This LTB universe model has a void with size comparable to the Hubble horizon scale. We first determine the decoupling epoch in this LTB universe model by an approximate analytical condition under a few simplified assumptions on the physical quantities at that epoch. Then we calculate the cosmic microwave background (CMB) anisotropy observed in the rest frame of clusters of galaxies which are assumed to be at rest in the spatial comoving coordinates of the LTB universe model. We find that the obtained temperature anisotropies are dominated by dipole, although there may exist higher multi-poles in general. We may interpret this dipole anisotropy as the drift velocity of a cluster of galaxies relative to the CMB rest frame. Hence it gives rise to the kSZ effect. We calculate this effect and compare it with observational data. We find that if we assume the conventional adiabatic perturbation scenario at the time of decoupling, the drift velocity of clusters of galaxies becomes unacceptably large. Conversely, this observational constraint may be relaxed by introducing a non-adiabatic (i.e., primordially isocurvature) component of inhomogeneities at the time of decoupling. However, our result indicates that the necessary isocurvature perturbation amplitude is very large.

20 pages, 8 figures

References in corpus (15)

• Confronting Lemaitre-Tolman-Bondi models with Observational Cosmology
• A Test of the Copernican Principle
• CMB anisotropies seen by an off-center observer in a spherically symmetric inhomogeneous universe
• Inhomogeneity and the foundations of concordance cosmology
• Looking the void in the eyes - the kSZ effect in LTB models
• Can we avoid dark energy?
• Testing the Void against Cosmological data: fitting CMB, BAO, SN and H0
• Scalar Perturbations on Lemaitre-Tolman-Bondi Spacetimes
• Precision cosmology defeats void models for acceleration
• Local Void vs Dark Energy: Confrontation with WMAP and Type Ia Supernovae
• The radial BAO scale and Cosmic Shear, a new observable for Inhomogeneous Cosmologies
• The Cosmic Microwave Background in an Inhomogeneous Universe - why void models of dark energy are only weakly constrained by the CMB
• Solving the Inverse Problem with Inhomogeneous Universes
• CMB observations in LTB universes: Part I: Matching peak positions in the CMB spectrum
• Analytic formulae for the off-center CMB anisotropy in a general spherically symmetric universe

Cited by in corpus (27)

• Is the Observable Universe Consistent with the Cosmological Principle?
• Inhomogeneous cosmological models: exact solutions and their applications
• Establishing homogeneity of the universe in the shadow of dark energy
• Observational constraints on inhomogeneous cosmological models without dark energy
• 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
• Reconstruction of the remote dipole and quadrupole fields from the kinetic Sunyaev Zel'dovich and polarized Sunyaev Zel'dovich effects
• Reconciling the local void with the CMB
• The intrinsic bispectrum of the Cosmic Microwave Background [PhD thesis]
• Planck intermediate results. XIII. Constraints on peculiar velocities
• Tension in the Void: Cosmic Rulers Strain Inhomogeneous Cosmologies
• Large scale structure simulations of inhomogeneous LTB void models
• Can decaying modes save void models for acceleration?
• Complete solutions to the metric of spherically collapsing dust in an expanding spacetime with a cosmological constant
• The isotropic blackbody CMB as evidence for a homogeneous universe
• The Metric of the Cosmos from Luminosity and Age Data
• What if Planck's Universe isn't flat?
• CMB dipoles and other low-order multipoles in the quasispherical Szekeres model
• Evolution of density perturbations in large void universe
• Simulated reconstruction of the remote dipole field using the kinetic Sunyaev Zel'dovich effect
• Observational Constraint on Spherical Inhomogeneity with CMB and Local Hubble Parameter
• Testing LTB Void Models Without the Cosmic Microwave Background or Large Scale Structure: New Constraints from Galaxy Ages
• 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
• Comparison of two approximation schemes for solving perturbations in a LTB cosmological model
• Newtonian self-gravitating system in a relativistic huge void universe model