Global Constraints On Key Cosmological Parameters

TL;DR

This paper combines supernova, X-ray, and BBN data to estimate current cosmological parameters, finding good agreement with high-redshift measurements and CMB data under certain conditions.

Contribution

It provides a comprehensive analysis of cosmological parameters using multiple data sources, highlighting consistency across different epochs and observational methods.

Findings

Current baryon density agrees with BBN estimates under flat universe assumption.

Baryon density at z=1100 from CMB is consistent with local estimates.

Results support a flat universe with low primordial deuterium abundance.

Abstract

Data from Type Ia supernovae, along with X-ray cluster estimates of the universal baryon fraction and Big Bang Nucleosynthesis (BBN) determinations of the baryon-to-photon ratio, are used to provide estimates of several global cosmological parameters at epochs near zero redshift. We show that our estimate of the present baryon density is in remarkably good agreement with that inferred from BBN at high redshift, provided the primordial abundance of deuterium is relatively low and the Universe is flat. We also compare these estimates to the baryon density at z = 1100 as inferred from the CMB angular power spectrum.