The Evolution of the Cosmic Microwave Background

Abstract

We discuss the time dependence and future of the Cosmic Microwave Background (CMB) in the context of the standard cosmological model, in which we are now entering a state of endless accelerated expansion. The mean temperature will simply decrease until it reaches the effective temperature of the de Sitter vacuum, while the dipole will oscillate as the Sun orbits the Galaxy. However, the higher CMB multipoles have a richer phenomenology. The CMB anisotropy power spectrum will for the most part simply project to smaller scales, as the comoving distance to last scattering increases, and we derive a scaling relation that describes this behaviour. However, there will also be a dramatic increase in the integrated Sachs-Wolfe contribution at low multipoles. We also discuss the effects of tensor modes and optical depth due to Thomson scattering. We introduce a correlation function relating the sky maps at two times and the closely related power spectrum of the difference map. We compute the evolution both analytically and numerically, and present simulated future sky maps.

23 pages, 11 figures; references added; one figure dropped and minor changes to match published version. For high-resolution versions of figures and animations, see http://www.astro.ubc.ca/people/scott/future.html

References in corpus (22)

• First Year Wilkinson Microwave Anisotropy Probe (WMAP) Observations: Determination of Cosmological Parameters
• Wilkinson Microwave Anisotropy Probe (WMAP) Three Year Results: Implications for Cosmology
• HEALPix -- a Framework for High Resolution Discretization, and Fast Analysis of Data Distributed on the Sphere
• Efficient Computation of CMB anisotropies in closed FRW models
• The Cosmological Parameters 2006
• Big-Bang nucleosynthesis (Particle Data Group mini-review)
• Phantom Energy and Cosmic Doomsday
• A Line of Sight Approach to Cosmic Microwave Background Anisotropies
• The Cosmic Microwave Background Spectrum from the Full COBE/FIRAS Data Set
• Three-Year Wilkinson Microwave Anisotropy Probe (WMAP) Observations: Temperature Analysis
• Cosmic Microwave Background Anisotropies
• Calibrator Design for the COBE Far Infrared Absolute Spectrophotometer (FIRAS)
• Microwave Background Constraints on Cosmological Parameters
• Cosmic Confusion: Degeneracies among Cosmological Parameters Derived from Measurements of Microwave Background Anisotropies
• Dipole Anisotropy in the COBE DMR First-Year Sky Maps
• Tensor Perturbations in Inflationary Models as a Probe of Cosmology
• Toward Understanding CMB Anisotropies and Their Implications
• Future Evolution of Structure in an Accelerating Universe
• Large-Angle Cosmic Microwave Background Anisotropies in an Open Universe
• The Return of a Static Universe and the End of Cosmology
• Cosmic microwave background constraints on the epoch of reionization
• The Long-Term Future of Extragalactic Astronomy

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