Microwave background anisotropies and non-linear structures II. Numerical computations
نویسنده
چکیده
A new method for modelling spherically symmetric inhomogeneities is applied to the formation of clusters in an expanding Universe. We impose simple initial velocity and density perturbations of finite extent and we investigate the subsequent evolution of the density field. Photon paths are also calculated, allowing a detailed consideration of gravitational lensing effects and microwave background anisotropies induced by the cluster. We apply the method to modelling high-redshift clusters and, in particular, we consider the reported microwave decrement observed towards the quasar pair PC1643+4631 A&B. We also consider the effect on the primordial microwave background power spectrum due to gravitational lensing by a population of massive high-redshift clusters.
منابع مشابه
CMB Anisotropies at Second-Order II: Analytical Approach
We provide an analytical approach to the second–order Cosmic Microwave Background (CMB) anisotropies generated by the non–linear dynamics taking place at last scattering. We study the acoustic oscillations of the photon–baryon fluid in the tight coupling limit and we extend at second– order the Meszaros effect. We allow for a generic set of initial conditions due to primordial nonGaussianity an...
متن کاملCMB anisotropy: deviations from Gaussianity due to non-linear gravity
Non-linear evolution of cosmological energy density fluctuations triggers deviations from Gaussianity in the temperature distribution of the cosmic microwave background. A method to estimate these deviations is proposed. N-body simulations – in a ΛCDM cosmology – are used to simulate the strongly non-linear evolution of cosmological structures. It is proved that these simulations can be combine...
متن کاملTexture-induced microwave background anisotropies.
We use numerical simulations to calculate the cosmic microwave background anisotropy induced by the evolution of a global texture field, with special emphasis on individual textures. Both spherically symmetric and general configurations are analysed, and in the latter case we consider field configurations which exhibit unwinding events and also ones which do not. We compare the results given by...
متن کاملMicrowave background anisotropies due to non - linear structures in open and Λ universes
A new method arising from a gauge-theoretic approach to general relativity is applied to the formation of clusters in an expanding universe. The three cosmological models (Ω0=1, ΩΛ=0), (Ω0=0.3, ΩΛ=0.7), (Ω0=0.3, ΩΛ=0) are considered, which extends our previous application (Lasenby et al. 1999, Dabrowski et al. 1999). A simple initial velocity and density perturbation of finite extent is imposed...
متن کاملNon-Gaussianity of Large-Scale Cosmic Microwave Background Anisotropies beyond Perturbation Theory
We compute the fully non-linear Cosmic Microwave Background (CMB) anisotropies on scales larger than the horizon at last-scattering in terms of only the curvature perturbation, providing a generalization of the linear Sachs-Wolfe effect at any order in perturbation theory. We show how to compute the n-point connected correlation functions of the large-scale CMB anisotropies for generic primordi...
متن کامل