Model-independent reconstruction of growth index via Gaussian process

In this paper, the reconstructed growth index gamma(z) is updated by jointed combination from Pantheon+ SNe Ia samples, the observed Hubble data points H(z) at the background level, and redshift space distortion measurements of f sigma 8(z) at the linear perturbation level via Gaussian process. The reconstructed results show that the currently available data points suggest a mild time varying growth index at low redshifts within 3 sigma regions. No significant deviation from Lambda CDM cosmology in GR within 3 sigma regions was found, while the growth indices for the f(R) and the Dvali-Gabadadze-Porrati gravity are at the boundaries of 3 sigma regions.

Automated summary

In this paper, the reconstructed growth index is updated using a combination of Pantheon+ SNe Ia samples, observed Hubble data points, and redshift space distortion measurements. The results suggest a mild time varying growth index at low redshifts within the available data points. No significant deviation from the ΛCDM cosmology in GR was found within the 3 sigma regions, while the growth indices for f(R) and Dvali-Gabadadze-Porrati gravity are at the boundaries of the 3 sigma regions.