Current cosmological constraints on the curvature, dark energy and modified gravity

TL;DR

This paper uses multiple cosmological observations to test models of the universe's geometry and dark energy, confirming flatness and ruling out some modified gravity models, while highlighting current data limitations.

Contribution

It provides comprehensive constraints on cosmological models using diverse data sets, including supernovae, BAO, CMB, and growth factors, with new insights on the Dvali-Gabadadze-Porrati model.

Findings

The ΛCDM model is consistent with current data.

The Dvali-Gabadadze-Porrati model is excluded at more than 3σ.

The universe is nearly flat.

Abstract

We apply the Union2 compilation of 557 supernova Ia data, the baryon acoustic oscillation measurement of distance, the cosmic microwave background radiation data from the seven year Wilkinson Microwave Anisotropy Probe, and the Hubble parameter data to study the geometry of the Universe and the property of dark energy by using models and parametrizations with different high redshift behaviours of $w(z)$. We find that $\Lambda$CDM model is consistent with current data, that the Dvali-Gabadadze-Porrati model is excluded by the data at more than $3\sigma$ level, that the Universe is almost flat, and that the current data is unable to distinguish models with different behaviours of $w(z)$ at high redshift. We also add the growth factor data to constrain the growth index of Dvali-Gabadadze-Porrati model and find that it is more than $1\sigma$ away from its theoretical value.