Measurements of H0 and reconstruction of the dark energy properties from a model-independent joint analysis

Gaussian processes (GP) provide an elegant and model-independent method for extracting cosmological information from the observational data. In this work, we employ GP to perform a joint analysis by using the geometrical cosmological probes such as Supernova Type Ia (SN), Cosmic chronometers (CC), Baryon Acoustic Oscillations (BAO), and the H0LiCOW lenses sample to constrain the Hubble constant H0, and reconstruct some properties of dark energy (DE), viz., the equation of state parameter w, the sound speed of DE perturbations cs2, and the ratio of DE density evolution X=rho de/rho de,0. From the joint analysis SN+CC+BAO+H0LiCOW, we find that H0 is constrained at 1.1% precision with H0=73.78 +/- 0.84kms-1Mpc-1, which is in agreement with SH0ES and H0LiCOW estimates, but in similar to 6.2 sigma tension with the current CMB measurements of H0. With regard to the DE parameters, we find cs2<0 at 2 sigma at high z, and the possibility of X to become negative for z>1.5. We compare our results with the ones obtained in the literature, and discuss the consequences of our main results on the DE theoretical framework.

Automated summary

In this study, Gaussian processes were used to extract cosmological information and perform analysis with geometric cosmological probes to constrain the Hubble constant H0 and reconstruct properties of dark energy. It was found that H0 was significantly constrained, and some peculiarities were observed in the dark energy parameters at high z.