Constraints on the Dark Side of the Universe and Observational Hubble Parameter Data

TL;DR

This review discusses observational Hubble parameter data, focusing on measurement methods, their sources of error, and their role in constraining dark matter, dark energy, and the universe's expansion history.

Contribution

It provides a comprehensive overview of the two main methods for measuring H(z), including their principles, errors, and applications in cosmology.

Findings

H(z) data helps constrain dark energy models

Differential age and BAO methods are key measurement techniques

Future observations will significantly improve data quality

Abstract

This paper is a review on the observational Hubble parameter data that have gained increasing attention in recent years for their illuminating power on the dark side of the universe --- the dark matter, dark energy, and the dark age. Currently, there are two major methods of independent observational H(z) measurement, which we summarize as the "differential age method" and the "radial BAO size method". Starting with fundamental cosmological notions such as the spacetime coordinates in an expanding universe, we present the basic principles behind the two methods. We further review the two methods in greater detail, including the source of errors. We show how the observational H(z) data presents itself as a useful tool in the study of cosmological models and parameter constraint, and we also discuss several issues associated with their applications. Finally, we point the reader to a future prospect of upcoming observation programs that will lead to some major improvements in the quality of observational H(z) data.