Measurement on the cosmic curvature using the Gaussian process method

TL;DR

This paper employs a model-independent Gaussian process method to reconstruct the cosmic expansion history and assess the universe's spatial curvature, finding results consistent with a flat universe within 2σ confidence.

Contribution

It introduces a novel, model-independent approach combining cosmic chronometers, supernovae, and redshift space distortions data to measure cosmic curvature.

Findings

Results are consistent with a flat universe within 2σ confidence.

The method effectively combines multiple data sources for curvature measurement.

No deviation from the ΛCDM model was observed.

Abstract

Inflation predicts that the Universe is spatially flat. The Planck 2018 measurements of the cosmic microwave background anisotropy favour a spatially closed universe at more than 2$\sigma$ confidence level. We use model independent methods to study the issue of cosmic curvature. The method reconstructs the Hubble parameter $H(z)$ from cosmic chronometers data with the Gaussian process method. The distance modulus is then calculated with the reconstructed function $H(z)$ and fitted by type Ia supernovae data. Combining the cosmic chronometers and type Ia supernovae data, we obtain $\Omega_{k0}h^2=0.102\pm 0.066$ which is consistent with a spatially flat universe at the 2$\sigma$ confidence level. By adding the redshift space distortions data to the type Ia supernovae data with a proposed novel model independent method, we obtain $\Omega_{k0}h^2=0.117^{+0.058}_{-0.045}$ and no deviation from $\Lambda$CDM model is found.