Measurement on the cosmic curvature using the Gaussian process method


الملخص بالإنكليزية

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 $Omega_{k0}h^2=0.102pm 0.066$ 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.

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