Results from the Wilkinson Microwave Anisotropy Probe

TL;DR

WMAP provided high-precision full-sky measurements of the cosmic microwave background, significantly refining cosmological parameters and strongly supporting key aspects of the standard cosmological model, including dark matter, dark energy, and inflation.

Contribution

This paper presents the first detailed analysis of WMAP's full-sky microwave background maps, constraining fundamental cosmological parameters with unprecedented accuracy.

Findings

Confirmed existence of non-baryonic dark matter

Provided strong evidence for cosmic inflation

Measured universe's age and composition with high precision

Abstract

The Wilkinson Microwave Anisotropy Probe (WMAP) mapped the distribution of temperature and polarization over the entire sky in five microwave frequency bands. These full-sky maps were used to obtain measurements of temperature and polarization anisotropy of the cosmic microwave background with the unprecedented accuracy and precision. The analysis of two-point correlation functions of temperature and polarization data gives determinations of the fundamental cosmological parameters such as the age and composition of the universe, as well as the key parameters describing the physics of inflation, which is further constrained by three-point correlation functions. WMAP observations alone reduced the flat $\Lambda$ cold dark matter ($\Lambda$CDM) cosmological model (six) parameter volume by a factor of >68,000 compared with pre-WMAP measurements. The WMAP observations (sometimes in combination with other astrophysical probes) convincingly show the existence of non-baryonic dark matter, the cosmic neutrino background, flatness of spatial geometry of the universe, a deviation from a scale-invariant spectrum of initial scalar fluctuations, and that the current universe is undergoing an accelerated expansion. The WMAP observations provide the strongest ever support for inflation; namely, the structures we see in the universe originate from quantum fluctuations generated during inflation.