The Case for Omega_M = 0.33 +/- 0.035

TL;DR

This paper combines recent measurements from clusters, CMB anisotropy, and mass power spectrum to estimate the matter density parameter Omega_M as approximately 0.33 with reduced bias.

Contribution

It provides a new, less biased estimate of Omega_M using multiple independent observational methods, improving upon previous light-based determinations.

Findings

Omega_M = 0.33 +/- 0.035

Omega_B = 0.039 +/- 0.0075

Consistent picture of matter and baryon densities

Abstract

For decades, the determination of the mean density of matter(Omega_M) has been tied to the distribution of light. This has led to a ``bias,'' perhaps as large as a factor of 2, in determining a key cosmological parameter. Recent measurements of the physical properties of clusters, cosmic microwave background (CMB) anisotropy and the power spectrum of mass inhomogeneity now allow a determination of Omega_M without ``visual bias.'' The early data lead to a consistent picture of the matter and baryon densities, with Omega_B = 0.039 +/- 0.0075 and Omega_M = 0.33 +/- 0.035.