Constraining the curvature density parameter in cosmology

TL;DR

This paper constrains the cosmic curvature density parameter independently of specific cosmological models using Gaussian Processes and multiple observational data sets, finding results consistent with a flat universe within 2-3 sigma.

Contribution

It introduces a model-independent method to constrain cosmic curvature using Gaussian Processes combined with diverse cosmological observations.

Findings

Results are consistent with a flat universe within 2σ for background data.

Adding RSD data maintains consistency with flatness mostly within 2σ.

Constraints are obtained over the redshift range 0<z<2.

Abstract

The cosmic curvature density parameter has been constrained in the present work independent of any background cosmological model. The reconstruction is performed adopting the non-parametric Gaussian Processes (GP). The constraints on $\Omega_{k0}$ are obtained via a Markov Chain Monte Carlo (MCMC) analysis. Late-time cosmological probes viz., the Supernova (SN) distance modulus data, the Cosmic Chronometer (CC) and the radial Baryon Acoustic Oscillations ($r$BAO) measurements of the Hubble data have been utilized for this purpose. The results are further combined with the data from redshift space distortions (RSD) which studies the growth of large scale structure in the universe. The only \textit{a priori} assumption is that the universe is homogeneous and isotropic, described by the FLRW metric. Results indicate that a spatially flat universe is well consistent in 2$\sigma$ within the domain of reconstruction $0<z<2$ for the background data. On combining the RSD data we find that the results obtained are consistent with spatial flatness mostly within 2$\sigma$ and always within 3$\sigma$ in the domain of reconstruction $0<z<2$.