$H_0$ from cosmic chronometers and Type Ia supernovae, with Gaussian processes and the weighted polynomial regression method

Abstract

We derive new constraints on the Hubble parameter $H_0$ using the available data on $H(z)$ from cosmic chronometers (CCH), and the Hubble rate data points from the supernovae of Type Ia (SnIa) of the Pantheon compilation and the Hubble Space Telescope (HST) CANDELS and CLASH Multy-Cycle Treasury (MCT) programs. We employ two alternative techniques, Gaussian Processes (GPs) and the Weighted Polynomial Regression (WPR) method, to reconstruct the Hubble function, determine the derived values of $H_0$, and compare them with the local HST measurement provided by Riess {\it et al.} (2018), $H_0^{{\rm HST}}=(73.48\pm1.66)$ km/s/Mpc, and with the Planck+$\Lambda$CDM value, $H_0^{{\rm P18}}=(66.88\pm 0.92)$ km/s/Mpc. With GPs we obtain $H_0=(67.99\pm 1.94)$ km/s/Mpc, and with the WPR method $H_0=(68.90\pm 1.96)$ km/s/Mpc. Both are fully compatible at $<1\sigma$ c.l., and also with $H_0^{{\rm P18}}$. In contrast, they are in $\sim 2\sigma$ tension with $H_0^{{\rm HST}}$.